Fisheries management and development completion report to the State Planning Office for the period October 1, 1978-September 30, 1979

[From the U.S. Government Printing Office, www.gpo.gov]

FISHERIES MANAGEMENT AND DEVELOPMENT

COMPLETION REPORT
to the State Planning Office
for the Period October 1, 19 73- Sept ember 30, 1979

Volume III

Element D: Characterization of the Shellfisheries

Maine Department of Marine Resources Edited by: C. J. Walton
Fi sheries Research Laboratory
West Boothb y 'Harbor, Maine 04575 Project '.Manager: V. C.,Anthonv
33-5572

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TABLE OF CONTENTS
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VOLUME I

Executive Summary

Page
VOLUME II

Introduction by V. C. Anthony ......................................... 1

Element A: Bottom Trawl Survey by C. J. Walton ....................... 4
Element A-1: Inshore Groundfish Survey - R/V Explorer ........... 5
Element A-2: Maine Coastal Survey - R/V Fishfinder ............... 8
Element A-3: Offshore Summer Cruise - R/V Challenge ............. 19
Summary .......................................................... 19

Element B: Establishment of a Fisheries Data Base for Managing
Maine's Commercial and Recreational Fisheries by
V. C. Anthony, C. J. Walton, E. P. Creaser, Jr. and
D. B. Sampson ............................................. 21
Introduction: ..................................................... 22

Element B-1: Work Program ....................................... 23
Element B-2: Evaluation of Existing Programs for the
Collection of Landings Data ........................ 24
Element B-3: Evaluation of the N.M.F.S'. Logbook System .......... 54
Element B-4: Review and Automate D.M.R. Licensing and
Permit System ...................................... 68
Element B-5: Survey the Fishing Industry to Determine
Landing Patterns by Species, Area and Time .......... 73
Element B-6: Determine Industry Sectors where Landings
do not Reflect Catches ............................. 136

Element C: Characterization of the Recreational Fisheries by
C. J. Walton .............................................. 145

TABLE OF CONTENTS (continued)

VOLUME III

Pajae
Element D: Characterization of the Shellfisheries ................... 196

Element D-1: A Characterization of the Soft Clam
Fishery of Maine by W. R. Welch ................... 196
Element D-2: A Characterization of the Northern Shrimp
Fishery of Maine by A. P. Stickney ................ 243

Element D-3: A Characterization of the Maine Lobster
Fishery of Maine by W. R. Welch ................... 294
Element D-4: A Characterization of the Scallop Fishery
of Maine by C. J. Walton .......................... 326

Element D-5: A Characterization of the Cancer Crab
Fishery Along the Coast of Maine by
J. Cowger and J. Krouse ........................... 359

Element D-6: A Characterization of the Maine Mussel
Fishery by J. Hurst ............................... 376

VOLUME IV

Element E: The Economic Impact of Fisheries in the State of Maine ... 388

Element E-1: Summary ........................................... 391
Element E-2: An Input-Output Table Designed to Assess
the Impact of the Fishery on the Maine
Economy ........................................... 405
Element E-3: Input-Output Results .............................. 419
Element E-4: Appendices ........................................ 443

I: Introduction to Input-Output Analysis .................. 443

II: Technical Notes ........................................... 457

fABLE OF CONTENTS (continued)

Page
VOLUME IV Element E-4: Appendices

III: Data and Methods Used to Estimate Input
Coefficients for the Finfish (except Herring)
Sector ................................................... 469

IV: Estimation Techniques Used in Compiling
the Herring/Menhaden Sector for the Maine
Input-Output Table ....................................... 501
V: Input-Output Estimates for the Lobster/
Crab/Scallop Sector ...................................... 517
VI: Data and Procedures Used to Estimate Technical
Coefficients for the Clam/Worm Sector .................... 534

VII: The Economic Value of Soft-Shelled Clam
(Ata arenaria) Production in Maine ........................ 553

196

ET, NT D-1: A CHARACTERIZATION

.OF

THE SOFT-SHELL CLAM FISHERY OF MAINE

Walter R. Welch

197

TABLE OP CONTENTS
Page

List of tables ............................................. 198

List of figures ..... ..................................... o. 199

Introduction ............................................... 200

Distribution of the resource ............................... 201

Availability of the resource ............. o....... o ......... 202

Status of stock assessment ............ o ............... 203

Variations in abundance ............................... 205

Influence of managed areas ............................. 208

Maine's problems in availability ............... ...... 209

Harvesting .................................... o........ o ... 213

Personnel .................... o ........................ 213

Methods ................ I .............................. 215

Effects of economic conditions on harvesting .......... 216

Effects of legal constrainst on harvesting ............ 218

Maine's problems in harvesting ........................ 222

References and literature cited ........................ 224

198

TABLES
Page

Table D-1-1. Landings of soft-shell clams in Maine ......... 226

Table D-1-2. Soft-shell clam growing areas and their

estimated production capacity, 1978 ........... 227

Table D-1-3. Status of resource assessment and clam

management, 1978 .............................. 228

Table D-1-4. Summary of Table D-1-3 ........................ 230

Table D-1-5. Processing of clams through depuration plants,

1974-1978 ..................................... 231

Table D-1-6. Commercial clam areas with unrestricted

opening due to municipal and private

pollution abatement, 1970-1978 ................ 232

Table D-1-7. Commercial clam areas with conditional

(seasonal) opening due to municipal and

private pollution abatement, 1970-1978 ........ 233

Table D-1-8. Commercial clam areas opened to depuration

digging due to municipal and private

pollution abatement, 1970-1978 ................ 234

Table D-1-9. Number of commercial shellfish licensesf

1942-1978 ..................................... 235

Table D-1-10. Fishing effort of clam diggers, 1973 .......... 236

Table D-1-11. Extrapolation of Table D-1-10 data to

amounts of clams harvested .................... 237

Table D-1-12. Age-profile of commercial shellfishermen,

1974 .......................................... 238

199

FIGURES
Page

Figure D-1-1. Total landings of soft-shell clams in Maine,

1887-1978 .................................... 239

Figure D-172. State of Maine with county and region

outlines ..................................... 240

Figure D-1-3. Annual landings of soft-shell clams,

average annual price per pound of meats, and

annual total commercial shellfish licenses,

1942-1978 .................................... 241

Figure D-1-4. Age profile of 5,333 commercial

shellfishermen, 1974 ......................... 242

200

INTRODUCTION

The soft-shell clam Wya arenaria) was, in 1978, as it has generally

been, the second most valuable marine reso urce in Maine in terms of

landed value. The 1978 landings of 6,007,234 pounds of meats, valued at

$7,469,611 at first sale, was second only to the American lobster in the

state of Maine.

The clam resource is one of Maine's most widely exploited resources.

The fact that it continues to produce as abundantly as it does is more

of a testimonial to its prolificacy and resilience to environmental abuse

than to the relatively meager results which the Department of Marine

Resources (DMR) and resource-minded members of the State Legislature and

municipal governments have been able to produce.

We believe the soft-shell clam resource has a large potential for

substantially increased levels of producti on through the enlightened use

of culture and management methods.

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DISTRIBUTION OF THE RESOURCE

The soft-shell clam is found on both coasts of North America, in

Europe, and along the northeast coast of Asia. On the Atlantic coast

of North America it is found from Labrador to Cape Hatteras, North

Carolina (Hanks, 1963).

In Maine, this clam is found all along the coast, in nearly all

places where the habitat is suitable. It mainly occupies the intertidal

zone, ranging from the upper third of the zone, reaching maximum density

in the upper part of the lower third of the intertidal zone, and commonly

extending to or slightly below mean low water. In some places, clams are

found subtidally, but the actual extent of numbers or depth is not known.

The most productive clam flats are those with sediments of a silt-sand

mixture, but clams can be found in nearly any type of sediment that they

can burrow into, from coarse gravel to soft, organic silts and clays.

These most productive flats may be in salt-marsh creek systems in the

southwestern part of the state or in coves and bays and along the shores

of estuaries all along the coast. Exposed, well-washed, sandy beaches

are not generally populated.

The specific locations of productive clam flats are much too numerous

to be described in narrative form. They may be found included in the

resource maps of the Maine Coastal Inventory, Fish and Wildlife Series

2 (State Planning office, undated).

2.02

AVAILABILITY OF THE RESOURCE

Over the history of recorded catch data, the quantities of Maine

clams appearing on the market have fluctuated widely (Table D-1-1, Figure D-1-1)

While we do not know all the causal factors influencing these

fluctuations, especially the earlier ones, we do know that in the last

four decades, such factors as war, competition in the market, and

environmental change have had strong influences in the quantities of

clams available,.as well as the quantities actually appearing on the

market.

Maine's commercial catch has been taken from the open (unpolluted)

portions of the clam producing areas shown on the resource maps of the

Maine Coastal Inventory, Fish and Wildlife Series 2 (State Planning

Office, undated). Region I (York, Cumberland, and Sagadahoc counties,

Figure 2) includes 24% of the state's total growing area, while its

open area constitutes 17% of the state's total growing area (Table 2).

Region II (Lincoln, Knox, and Waldo counties) includes 18% of the

state's total growing area, while its open area is 13% of the state's

total growing area. Region III (Hancock and Washington counties)

includes 58% of the state's total growing area, while its open area is

53% of the state's total growing area. Over the past 15 years the

catch from Region III has varied from 39 to 75% of the state's total,

while during the major part of the period the landings from that area

were well over 50% of the total.

203

OVERALL STATUS OF STOCK ASSESSMENT

The soft-shell clams in Maine are not considered for management

as a single stock. There are several practical reasons for this: 1)

municipalities have primary jurisdiction over the clams in their areas

and thus set up political boundaries for their management systems; 2)

the various municipalities have different management goals, based on

different socio-economic circumstances; and 3) the physical and

biological nature of the clam flats vary so from flat to flat, even

within municipalities, that each clam flat has to be surveyed and

considered on its own merits; the area to area variations are even

greater and more significant along the Maine coast as a whole.

In view of these considerations, the estimation of clam stocks is

done on a piecemeal, localized basis, rather than on a state-wide,

single stock basis. With stimulation from DMR, and with the advice and'

assistance of the DMR area biologists, the municipalities participating

in clam management carry out their own surveys to determine: 1) the

standing crop of clams, 2) relative growth rates, 3) year class

composition, 4) harvestable fraction, and 5) recommended means of

administering the harvesting. These surveys are updated periodically,

when deemed advisable by the towns or the area biologists.

Itmay be seen, therefore, that an accurate numerical representation

of the total clam stocks in Maine is not possible under present

conditions. However, Goggins (1975) attempted to develop the best

204

estimates of potential clam production from information available at

the time. From detailed interviews with area biologists, coastal

wardens, clam diggers, and other coastal residents, he obtained data

on number, location, and acreage of clam-producing areas and estimates

of volumes of clams taken from such areas. The sizes of individual

producing areas ranged from I to over 500 acres, and their carrying

capacity (potential production) ranged between less than 25 and 300

.bushels per acre. While the original data were obtained on the basis

of individual areas and by towns, to make the array more workable

it was grouped by counties and regions (Figure D-1-2). From the total

growing areas and the total production capacity of those areas were

subtracted the acreage of growing areas closed because of pollution

and the estimated production capacity of these areas. The difference

was the total acreage of growing area open to digging and the estimated

production capacity of that open area. Table D-1-2 is adapted from Goggins

(1975) data and updated through 1978 by adjusting for the acreage of

formerly closed flats opened to unlimited digging through pollution

abatement (Winters, 1979), and by using the 1978 catch data. From

Table 2 it can be seen that the 1978 catch was 12% of the total

estimated production capacity of the open areas in the state, and that

this could be increased by about one-fifth if all closed areas could

be opened.

A judgment of the relative status of the stocks can also be made

205

through consideration of: 1) the results of town surveys that are

reasonably correct, 2) the observations of DMR field personnel, 3) the

current status of the commercial catch, and 4) a knowledge of the

influence of demand and price on the level of the commercial catch.

The status of clam stocks in Maine at the end of 1978, for example,

may be characterized as only fair because of; 1) severe depletion of

harvestable clams in at least 30% of the state's open area (Regions I

and II, Table D-1-.-2), 2), general lack.of-succes-sful year classes (except

for 1976) throughout the same area, 3) moderate to heavy predation by

green crabs (Carcinus maenas) over the past 5 to 6 years in 56% of the

open area (Regions I and II and Hancock County, Table 2) and 4)

intensive digging, stimulated by high prices, which has cut heavily into

stocks in Hancock and Washington Counties.

VARIATIONS IN ABUNDANCE

A primary cause of variations in availability of clams to the

market is variability in their natural abundance. This may result from

either or both natural and man-related factors. The young, as

planktonic larvae, are produced in enormous quantities but are also

subject to enormous losses. They may be swept out to sea and lost to

coastal bays and estuaries, or they may be consumed by zooplankton, filter

feeders, or other predators. After metamorphosis, from the swimming

sta ge, and settlement to the bottom (when it becomes "set"), the young

clams utilize some byssal attachement and voluntary movement, but are

206

largely at the mercy of hydrographic forces which determine final

distribution. By the time the clams have reached 25 mm (1 inch) in

length, usually in the second summer, movement from most causes has

ceased, and the size of the year class may be determined. Ayres (1956)

has calculated that, in general, 1% of the set must survive to the

stage of reproduction for a population to remain stable.

The abundance of clams in the flats may be influenced by a number

of factors. Such factors as environmental conditions (pollution,

temperature, salinity, and others), diseases, and parasites have effects

varying with time and place, effects which are very difficult to

measure but whose total significance is minor compared with those

following.

Predation as a whole can affect nearly all sizes of clams in the

flats, from as small as 2 mm to at least as large as 75 mm (Dow and

Wallace, 1961). Predators include boring snails, crabs (green and

horseshoe), fish, and birds, but the most devastating in Maine has been

the green crab. During the warm period of the 19501s, green crabs

became sufficiently abundant all along the Maine coast to have

virtually eliminated market clams from the flats of southwestern Maine

and to a slightly less extent in other areas. Annual sets were

repeatedly destroyed before they reached even 1 year of age. The

annual landings of clams were reduced to an all-time low of 1.4 million

lbs. of meats by 1959 (Welch, 1968). The same sort of devastation

207

occurred in the southwestern half of Maine during the recent warm period

of the 1970's. Although annual sets were repeatedly destroyed over at

least a 5- to 6-year period, annual total landings were maintained at

a relatively high level by virtue of: 1) large reserve stocks of clams

accumulated during the 1960's; 2) increased digging pressure in

northeastern Maine in response to high prices; and 3) the output of

depuration plants, processing clams from mildly contaminated areas.

The likelihood of increased green crab predation can be predicted

from the cyclic occurrence of periods of elevated water temperatures,

but the severity of the predation and its effects on clam landings is

so dependent on many other factors (reserve stocks, prices, digging

intensity, output of depuration plants, influence of managed areas,

and extent of use of predation prevention methods) that the results

cannot be predicted at this time.

The other serious cause of loss of clams established in the flats

is digging mortality (that in addition to the actual removal of

harvested clams to market). Clams left in the flats by diggers are

subject to several types of risk: 1) being broken too severely to

survive; 2) being buried at a depth or in a position such that they

cannot obtain the necessary water supply to survive; and 3) being

exposed at the surface and subject to predation from birds, crabs, and

fish. Average losses for the state as a whole from the first two risks

alone were estimated to be 70% of the clams remaining in the flats each

208

time an area is dug (Glude, 1954), (Dow, Wallace, Taxiarchis, 1954).

From this it can be seen that repeated digging in popular areas causes

extremely heavy losses in clams which never reach market.

INFLUENCE OF MANAGED AREAS

The application of management methods can be expected to improve

the availability of clams to the market through such ef f ects as: 1) the

reduction of severe fishing mortality, 2) regulating product flow to

more nearly match market demands, and 3) taking fullest advantage of the

natural attributes (good setting, good survival, good growth) of clam

producing areas. Thus far, most management efforts in the state (by

municipalities) have been limited to- 1) resource surveys to determine

year-class structure, growth, and potential yield; 2) alternation of open

and closed periods to reduce unnecessary digging mortality in areas not

ready to harvest; 3) restricting digging to residents only, resident

quotas, or non-resident quotas; and 4) size limits on clam length. The

present estimate of acreage under some sort of management is 8,669

acres, or nearly one-fourth of the state's total open growing area

Tables D-1-3, D-1-4.

The influence of the supply of depurated clams on the total clam

market is relatively minor. Production for 1978 was 14,990 bu. (Table D-1-5)

or 3.7% of total landings for the year. This level of production can

be expected to hold even as it has over the past 5 years, or perhaps

increase somewhat over the next few years as pollution abatement efforts

209

continue. The utilization of these moderately-contaminated clams also

serves the purpose of: 1) providing additional employment, and 2)

reducing stocks of clams whichwould otherwise tempt illegal digging and

constitute law enforcement and public health problems.

In Maine, aquaculture of the soft-shell clam; that is, raising it

from egg to market, is non-existent in the commercial sense and therefore

exerts no influence on the availability of clams for market. In the

future, there may be practical usage of hatchery-raised young clams

(set or submarket size) for transplant to growing areas to supplement

deficiencies in natural setting. There are also possibilities in the

intensive culture of natural sets to increase growth rates and to reduce

natural and harvesting mortalities, but such endeavors do not as yet

seem economically feasible, nor as yet even technically feasible.

MAINE'S PROBLEMS IN AVAILABILITY

There are several problem areas which affect the availability of

clams to the market:

1. The primary obstruction to efficient management of our

clam.rescurces and enhancement of availability to the

market is the cumbersome and inadequate legal structure.

Whether the present arrangement continues, wherein the

towns have primary management responsibility, or whether

the state assumes primary responsibility, changes are

needed to: 1) improve the flexibility in implementing

210

management decisions, 2) to more readily enable the

designation of geographic (rather than political) management

units and 3) to provide adequate legal protection for clam

flats under management.

2. Pollution continues to be a major problem in that it still

ties up sone 18% of the state's potentially productive

acreage (Table D-1-2). Industrial contamination, heavy

metals, and oil spills are included, but domestic pollution

is by far the greatest contributor. Municipal and private

residence abatement of polluting practices is proceeding

at a modest rate and the future looks somewhat brighter

than it has been. Table D-1-6 shows the acreage and

estimated production of clams from areas that have had

unrestricted openings due to pollution abatement, 1970 to

1978; Table D-1-7 shows the same for areas with conditional

(seasonal) openings; and Table D-1-8 shows the same for areas

where pollution has been sufficiently reduced to permit

digging for depuration purposes.

Longevity, long-range effects, and significant of

oil, heavy metals, and radionuclide contamination is

largely unknown and needs investigation.

3. Paralytic shellfish poisoning (GonauZax tcmarensis toxin)

211

is a seasonally serious problem in that when it occurs,

it is generally during the season of greatest demand and

high prices; hence, the losses to the market come at the

Most unfavorable time of the year. Additionally, in times

of long period closures, the entire seafood market is

affected through general fear of the effects of the toxin.

The location and intensity of paralytic shellfish

poisoning (PSP) outbreaks are monitored by DMR, but there

is need for: 1) development of predictive capability to

be able to forecast unacceptable increases in toxicity;

2) development of detoxification methods to utilize clams

otherwise withheld from the market; and 3) determination

of the effects of PSP on clam physiology, reproduction,

growth, and survival, as well as its effects on other

forms of marine life.

4. Inadequate resource information is a hindrance to the

comprehensive management of the state's clam resource as

a whole. At present, resource surveys are, for the most

part, conducted only as required of the towns by DMR to

fulfill state requirements for the towns to be able to

pass their own ordinances pertaining to clam management.

Many clam-producing areas remain unsurveyed (76.2%,

Table D-1-4. Resource location maps (State Planning Office)

212

undated) give approximate locations of productive areas,

but quantitative surveys have yet to be made in many

cases. Data such as year class strengths, growth,

natural mortality, standing drop and potential yield are

.needed to make management decisions on all producing areas.

5. The problem of irregular or inadequate sets in many areas

renders regulation or management much more difficult.

There is a need for the development of practical methods

to circumvent such occurrences, such a s: 1) transplanting

of young clams from overpopulated or contaminated areas;

2) attracting or accumulating natural set metamorphosing

from the planktonic stagei,or migrating over the surface,

and 3) hatchery-raising juveniles for transplantation to

growing areas. Limited work on gear development, use,

and transplanting has been carried out in utilizing natural

accumulations of set, usually with considerable success

(Goggins, 1978). Specific and controlled studies need to

be carried out on such aspects as: 1) refinements in gear

and methods of use, 2) adaptability to various bottom types;

3) effects of dredging in the seed clam area; 4) repopula-

tion of the seed clam area; and 5) fate of the transplanted

clams (ability to burrow, mortality and other losses,

growth).

213

6. Growth can be so slow in some areas, particularly in

Hancock and Washington Counties, that clams require many

years (7-12, or even more) to reach a marketable size.

Effort is needed to try to develop means of utilizing

these stocks of clams, either by transplanting to

faster-growing areas, or by promoting faster growth in

each particular area.

HARVESTING

PERSONNEL

The Maine clam digger is, in many ways, the personification of the

highly independent fisherman who finds easy entry into a low investment

fishery. If he is industrious and stocks of clams allow it, he can make

a comfortable living for his family and remain relatively independent

of supervisors and time schedules. many, however, are not full-time

clam diggers, or do not produce the total catch potentially available

during each tide. Quotas are frequently set by buyers, particularly

when the demand is low, but many diggers tend to produce up to a

personal quota based on their actual requirements for money.

Capital investment is very low in this fishery. The bare minimum

required includes a pair of hip boots, a clam hoe, and several clam hods.

Motor vehicle transportation is usually required to areas with shoke

access, and a skiff and outboard motor may be required to get to areas

without land access, or to nearby islands.

214

Table D-1-9 and Figure D-1-3 show the number of commercial shellfish

licenses (state) issued over the past four decades. From Figure D-1-3, it

appears that the number of licenses rose a few years following the

increase in landings during the latter 1966's. The landings, licenses

and average price per pound then rose in parallel for a few years.

During the past 5 years, it appears that the overall availability of

clams (as indicated by the landings) has had more influence on the

number of licenses sold than the average price per pound, which has

continued to rise steeply.

Although the correlations exist as shown above, the total number

of commercial licenses sold by the state is not a very good measure of

the amount of effort going into harvesting the annual total landings.

Many license holders may not dig at all, or others perhaps only very

infrequently. A somewhat better indication of effort can be obtained

from TablelO derived from the last analysis of shellfish license

application questionnaires by DMR in 1973-74. From this table one can

see that 73% of the commercial license holders dig less than 6 months

out of the year, while 40% dig only a bushel or less per day. In Table

D-1-11, converting the effort data to amounts harvested, it is evident that

about three-quarters of the total clams dug per day are dug at the rate

of 1.1 to 3.0 bushels per day, while about two-thirds of the annual

landings are dug by men working from 3 to 8 months out of the year.

Fisheries are often spoken of as being manned by aging workers and

215

lacking a healthy influx of the young. The results shown in Table D-1-12

and Figure D-1-4 seem to contradict this idea in the case of shellfishermen.

It is evident from these data that a lot of young fishermen are in the

clam fishery, but the complete picture still may not be apparent. If

is entirely likely that the large percentages of younger diggers

repr esented in Table D-1-12 and Figure D-1-4 may also make up the sizable

groups shown in Table D-1-10 that dig minimal quantities per day during a

minimal number of months out of the year. In other words, they may make

up the major part of the part-time workers in the clam fishery. The

data to determine whether or not this possibility is true probably

exists in the questionnaires used by Goggins (1975), but the required

analysis has not as yet been run.

METHODS

In Maine, soft-shell clams can be taken only by implements operated

solely by hand, with the following exception. Under special license,

a hydraulic or mechanical soft-shell clam dredge can be operated for

aquaculture or research (DMR,, 1979). Under such circumstances the

harvesting of seed clams for transplanting has been carried out by

municipalities.

In a typcal clam digging operation, the digger uses 1 4- or 5-

tined, short-handled ford, called a clam hoe. The shape and angle of

the tines may be modified to meet a, digger's personal requirements or

to suit the type of sediment in the flats commonly dug. Two generalized

216

,methods of digging the clams are used. In the first, if clams are not

very deep in the flats (in hard sediments where clams cannot burrow

deeply), the clam hoe is pushed in to the optimum depth and tipped to

break out a solid chuck of flat. This chuck is tipped upside down

into the area behind it, previously dug, and the clams are picked off

the under side of the chunk. In the second and much more common

method, where clams are deep in sandy or muddy sediments, the top

layer of 3 to 5 inches is first skimmed off into the previously dug

hole behind it. Then a deeper chunk of flat is turned out, containing

or exposing the market-size clams. Both methods result in the burying

of many of the remaining clams, particularly the smaller ones in the

top 1 or 2 inches of flat, which has been dumped at the bottom of the

previously dug pit. Such clams have only a 50% chance of surviving

the burial. Breakage of clams in the process of digging averages

about 20% (Dow, Wallace, Taxiarchis, 1954) and less than 1% of those

broken can be expected to survive (Glude, 1954).

Clams dug out are placed in a clam hod, a slatted basket containing

1 to 2 pecks, are rinsed in nearby sea water, and are ready to be sold.

EFFECTS OF ECONOMIC CONDITIONS ON HARVESTING

The level of harvesting effort is influenced strongly at times by

the economic conditions, both local and distant. The demands of the

retail market have a direct and early effect on all levels of the supply

chain because nearly all of the products are handled in the fresh

217

condition and cannot be stockpiled. The output of the regular digger

is controlled to a considerable extent by instructions from his buyer

who may set a maximum quota to be dug, who will set the price, or who

will refuse to buy. usually, adjustment of the price offered is

sufficient to control the level of harvesting, but under more severe

reductions of production, the digger may be limited to a quota, or a

maximum amount that he can dig. The buyer prefers the quota to a layoff

because it keeps the regular diggers employed and tends to keep them

selling to the same buyer. Under extremely poor market conditions,

an absolute layoff may be necessary, which puts the digger out of

business unless he can Peddle his clams locally himself.

The most serious market competition the Maine soft-shell clam has,

even within Maine, is the Maryland soft-shell clam (same species). In

Chesapeake Bay, it is subtidal, fast-growing, and harvested by hydraulic

escalator dredges. It is used in some segments of the market because

it is often readily available; of desirable size; less often broken;

more evenly sized; with clean, white shell; and very competitive in

price.

Data are not available to determine how large a volume of clams are

brought into Maine from Maryland. DMR personnel believe, however4 that

the quantities are sufficiently large to affect prices in Maine. When

Maryland clams are readily available, the price to the diggers is held

down; when Maryland clams are not readily available in New England

218

markets and demand is strong, the Maine prices tend to rise.

Factors outside the clam market can exert some influence on the

level of harvesting. Seasonal employment in other fields can affect

harvesting, particularly if it comes during the high-demand summer

season. off-season jobs, suchas working in other fisheries, picking

blueberries, or wood-cutting, can be the result of lowered demand for

clams, but in summer the lure of higher pay, more desirable jobs, or a

change may. remove diggers from the harvesting scene. Another aspect of

the seasonal employment picture is that winter clam digging attracts

some individuals who cannot find other employment in a season when the

job market is poor.

EFFECTS OF LEGAL CONSTRAINTS ON HARVESTING

As described above, clam digging in Maine can only be done by hand.

Digging by clam hoe is inefficient and destructive, with an average loss
of 70%'of the clams left in the flats at each digging (Dow, Wallace,

Taxiarchis, 1954; Glude, 1954). About the best that can be said for

hand digging is that it requires small capital investment of the

fisherman and probably employs more people than a mechanized or hydraulic

method would.

The laws authorizing, defining, and regulating local controls over

clam harvesting are some of the most numerous and complex in the entire

clam fishery. Except for the enabling state laws, most of the regulations

are in the form of municipal ordinances and are aimed principally at:

219

regulating and/or licensing resident, non-resident, commercial, and

non-commercial diggers; establishing areas to be controlled; and

establishing size and catch limits.

The overall effect of local regulation on the level of harvesting

is undoubtedly a favorable one, although a numerical value cannot be

attached. The most important feature of such regulation is to limit

repeated digging (and hence unnecessary clam destruction) in areas

that are closed until ready for harvest. Overdigging, resulting in

further increases in mortality and depleted flats, can be avoided by

the municipal control of areas dug, number of licenses, catch limits,

and periods of digging.

State regulations do not include control of size limits of clams.

There are a number of reasons for this, the most important being: 1)

size limits, particularly the minimum size, are not applicable on a

statewide basis because of widely varying growth rates and maximum

sizes; 2) current management philosophy, considering the destructiveness

of the clam hoe-, is that the less frequently a clam flat is dug, the

better, hence each digging at prescribed intervals should be aimed at

removing all marketable clams at that time; 3) there is little, if any,

biological advantage to having a minimum size limit as long as most of

the commercial catch is made up of clams exceeding the minimum size at

spawning (25 to 35 mm, or 1 to 1-3/8"); and 4) in areas where a minimum

size limit might be advantageous to a more efficient use of the resource,

the municipality has the authority (through its ordinance) to establish

220

the desired minimum. In addition to the above, buyers and dealers are

free to establish their own lower size limits if it appears that diggers

are bringing in too many small clams which are not utilized by the

shucking houses.

The numerical effect of the general absence of a minimum size limit

on harvesting is unknown, but such absence has permitted the harvesting

of areas of stunted clams which seldom reach the 2-inch size; it has also

undoubtedly allowed better utilization of more clams in areas where

digging has been limited to prescribed periods.

The closing of clam producing areas because of public health

restrictions has prevented substantial quantities of clams from reaching

the market. These closures are:of four general types: 1) long-term

closures based on sustained levels of pollution (domestic or industrial)

that are too high to permit depuration; 2) public closures based on

sustained or seasonal levels of pollution which are sufficiently and

consistently low enough to permit utilization of clams by means of the

depuration process (in which case digging is by special permit and

strictly controlled); 3) seasonal closures or "conditional areas" .-which

are opened during seasons (usually winter) when pollution loads are low

or absent; and 4) emergency closures for such occasions as outbreaks of

paralytic shellfish poisoning (PSP) and which remain in effect only as

long as the unacceptable conditions prevail.

Table D-1-2 shows that 16% of the state's total estimated production

capacity is in closed growing areas, varying from 91% of York County to

221

8% of Washington and Hancock counties. However, since 1974, these levels

of closure have been reduced from 20% of the state's total, varying from

98% of York County.to 9% of Washington County (Goggins, 1975; Winters,

1979). This reduction has been possible because of continuing abatement

of municipal and private residential domestic pollution. In the period

1970 through 1978, 1,577 acres have been reclaimed in this manner, with

an estimated production capacity of 156,617 bushels of clams, valued at

$3,4.45,574 (Table D-1-6).

During the same period 197 0-1978, 1,836 acres were opened to

depuration digging for the same reason. These areas were estimated

to be capable of producing 141,114 bushels of clams, valued at $2,116,710

(Table D- 1- 8)

Again during the same period, 645 acres were opened to conditional

(seasonal) digging because pollution levels were reduced, usually in

winter, to a point where open digging (not requiring depuration) could

be permitted. These areas were estimated to be capable of producing

37,998 bushels of clams, valued at $835,956 (Table D-1-7).

From the records of the depuration plants (Table D-1-5), one may see

that actual amounts of clams processed have varied from 11,479 to 15,978

bushels per year, constituting 2.9 to 3.1% of total annual landings of

clams.

It appears that substantial progress is being made in the freeing

of productive clam flats from pollution and returning them to commercial

and recreational use.

222

MAINE'S PROBLEMS IN HARVESTING

The greatest problem in harvesting is a supply which fluctuates

widely and even at its best is less than optimum. As-described in a

previous section, the principal reasons for this are: 1) stocks locked

up in polluted areas, 2) stocks reduced by cyclically-severe predation

or unreliable setting, and 3) lack of adequate management of existing

stocks.

In addition to these aspects of the supply problem, there are

other problems directly related to harvesting:

1. The irregularity and undependability in harvesting effort

makes it very difficult to maintain a constant or a desired

level of harvesting. Some diggers work steadkly;and dependably

'at their jobs, but a great deal of harvesting is done by

part-time diggers and those who have a tendency to produce

only enough to satisfy immediate monetary needs. Buyers find

it very difficult to balance actual market demands against the

ups and downs of harvesting.

2. Methods for improving harvesting, such as the development and

use of less destructive methods and gear, meet with little

interest and cooperation from the diggers. They have strong

preferences for the old ways and are very suspicious"of any

new methods or gear that might be less labor intensive and

thus reduce the need for manpower. Hydraulic dredges of

various types that have been proven efficient and relatively

223

non-destructive in certain types of areas have been bitterly

opposed by diggers who have seen themselves threatened by such

innovation.

3. The problem of thr tangle of municipal laws governing the who,

where, when, and how of clam harvesting could be much

simplified if the clam resource, state-wide, were a direct

responsibility of DMR. Because of the extreme variability in

the character of clam flats and the need for area-by-area

survey and mana gement, however, the monetary and manpower needs

of DMR would have to be increased greatly. Since such a

change is not likely, in the meantime the best that can be

accomplished by DMR is to coordinate municipal regulation

and to endeavor to have regulation based upon conservation

objectives.

4. A major problem in evaluating the effectiveness of various

types of management and various levels of management

intensity is the lack of feedback from harvesting a given

area. what is needed is total tally of the quantities of

clams coming from a particular management area. Only with

these data can the effectiveness of harvesting predictions

be judged, or refinements be made in management methods.

224

REFERENCES AND LITERATURE CITED

*Ayers, John C.

1956. Population dynamics of the marine clam, Mya arenaria

Linnol. and Oceanogr. 1:26-34.

Belding, David L.

1930. The soft-shelled clam fishery of Massachusetts. Commonwealth

of Massachusetts. Mar. Fish. Ser. 1, 65 pp.

*Dow, Robert L. and Dana E. Wallace.

1961. The soft-shell clam industry of Maine. U.S. Fish Widl. Serv.,

Circ. 110, 36 pp.

*Dow, Robert L. , Dana E. Wallace. and Louis N. Taxiarchis.

1954. Clam (Mya arenaria) breakage in Maine. Me. Dept. Sea and

Shore Fish. Res. Bull. No. 15, 4 pp.

Foster, Richard W.

1946. The genus Mya in the Western Atlantic. Johnsonia 2:29-35.

Glude, John B.

1954a. The effects of temperature and predators on the abundance of

the soft-shell clam, Mya arenaria, in New England. Trans. Amer. Fish.

Soc. 84:13-26.
14,
*Glude, John B.
1954b. Survival of soft-shell clams, Mya arenaria, buried at various t
depths. Maine Dept. Sea and Shore Fish., Res. Bull. 22, 26 pp.

*Goggins, Phillip L.

1975. Statewide comprehensive fish, wildlife, and management plan.

Maine Dept. of Mar. Resources, Completion Report, Proj. AFSC-13/FWAC-2,

128 pp.

*Cited in text.

225

*Goggins, Phillip L.

1978. The initiation of statewide intensive clam management. Maine

Dept. of Mar. Resources, Completion Report, Proj. 3-240-D, 97 pp.

*Hanks, Robert W.

1963. The soft-shell clam. U.S. Fish Wildl. Serv., Circ. 162, 16 pp.

*Maine Department of Marine Resources.

1979. Maine marine resources laws and regulations. 251 pp.

*Maine State Planning Office.

Undated. Maine coastal inventory, Fish and Wildlife 1 and 2.

Pfitzenmeyer, Hayes T. and Carl. N. Shuster.

1960. A partial bibliography of the soft-shell clam Mya arenaria L.

Maryland Dept. of Res. and Educ., Ches. Biol. Lab. Contri. No. 123, 29 pp.,

Prysunka, A.M., F.M. French, W.C. Dunham, and H.B. Metzger.

1977. An analysis of the dealer processor sector of the Maine soft-

shell clam industry, 1974. Univ. of Me., LSA Exp. Sta. Bull. 722,

41 pp,

Ropes, John W. and Alden P. Stickney.

1965. Reproductive cycle of Mya arenaria in New England. Biol. Bull.

128:315-327.

*Welch, Walter R.

1968. Changes in abundance of the green crab, Carcinus maenas (L.),

in relation to recent temperature changes. U.S. Bur. Comm. Fish., Fish.

Bull.:67, 2, pp. 337-345.

*Winters, Harold

1979. Survey of waste discharges to shellfishing areas, Me. Dept.

Mar. Res., Res. Ref. Doc. 79/3, 3 pp.

*Cited in text.

226

Table D-1-1.

Tan 4 4 nus c4 SO ":-Shel I C! in *4 a in C
(Frc.-. -'Cuair's , 11)75 --n,4 L!:,@ data

Pounds Pounds
Bushels of Meats Val,,e 9ushels of
Th - Price Mil- ?rice Thlolj- Pri ce ri --C,
sa@@
Year ds oer bu. lions per. lb. T@,ousazds Year sands pe@ bu. lions @-r lb. Thzusands
1887 407 .570 b-I .03E 2z-@ iuz@ 107 S. 1.6 3@'7
1686 400 .570 6-0 .03E 9' 5.6- i.4 .37F 5311
360 .690 5.4 8-@
1996 .046 24@
1697 353 -690 5-3 . 0 46 --44 96 12, Q.@-7 1., .44-' 79 4
S 7 ..;3: " E?: - -1 7.07 :.9 E94
189E 580 .480 i" .47
1899 547 .645 8.2 .04-@ 347, 12,- (.56 i.6 .437 787
1900 5FO .600 6.7 1 -2-,
.04@@ -153 'S,64 12C 6.a9 - .4@@
1901 50- .645 7-6 .043 329 ij4z 133 7.22 2.0 .462 -64
1902 507 .660 7-6 .044 333 1966 200 6.9@ 3.0 .162 1,367
1903 440 .750 6.6 .050 437 1967 213 6.9; 3.2 .462 1,479
1904 427 .765 E-4 .051 324 196S 227 6.29 @.4 .419 1,425
1905 413 .870 6-2 .058 356 1969 260 6.33 4.2 .422 1,753
1906 513 .735 7.7 .049 379 1970 353 7.13 5.3 .475 2,497
1907 607 .990 9-1 .066 602 1971 353 7.70 5.3 .513 2,6u,
1908 647 .840 9.7 .05r, 540 1972 407 9.06 6.1 .604 3,709
1909 487 1.01 7.3 .067 500 1973 484 11.78 7.3 .786 5,701
1910 627 1.14 9.4 .076 730 1974 394 11.46 5.9 .764 4,511
1911 520 1.11 7-8 .()74 580 1975 436 13.00 6.5 .869 5,692
1912 633 1.22 9-5 .081 768 1976 516 15.00 7.7 1.00 7,812
1913 347 .84 5.2 .05r. 291 1977 522 17.70 7.8 1.18 9,271
1914 413 1.16 6.2 .077 481 1978 400 18.65 6.0 1.24 7,469
1916 513 1.02 7-7 .068 524
1919 140 1.17 2.1 .078 163
1924 240 .96 3.5 .064 228
1929 447 1.05 6.7 .070 473
1930 660 .525 9.9 .035 349
1931 467 .51 7.0 .034 239
1932 487 .48 7-3 .032 234
1933 433 .51 6.5 .034 224
1935 467 .615 7-C) .041 286
1938 473 .675 7.1 .045 318
1939 333 .615 5-0 .041
1940 400 .600 6.0 .040 237
1941 453 .855 6.8 .057 390
1942 400 1.17 6.0 .078 470
1943 313 1.95 4-7 .130 614
1944 227 1.85 3.4 .123 415
1945 387 2.00 5-8 .133 776
1946 653 2.76 9.8 .185 11815
1947 527 2.85 7.9 .190 1,497
1948 600 3.02 9-0 .201 1,801
1949 573 2.48 8-6 .165 1,420
1950 460 2.58 6.9 .172 1,184
5-1 .232 1118?
1951 340 3.48
1952 367 4.41 j-5 .294 1,623
1953 280 5.00 4.2 333 1,382
1954 247 5.49 3.7 .366 1,360
2955 173 5.43 2-6 .362 949
19S6 167 5.36 2.5 .357 897
1957 133 5.64 2.0 .376 700

100 low *0 UO 40 Oft (00

Table"D-1-2.

Soft-Shall Clam Growing Areas and Their EStimated Production Capacity. 1976
[From Goggins. 1975 and updated to 1978 from Winters, 1979)

TO taI Total Open Open Growing Ares Closed*
Gro-inq Area Production Capacity rowinq Area Production Capacity Crowing Area
% % % % k
of of of of of of of of of of Of of of f
it, q. state Keg. State RAg. State State Reg. State Statt CoLutty Reg. State st:te
Act,-.% Vo t'l I Total bushels Total Total Acres Total Total Open Bushels Total Total Open Acres rotd i Total Total Closet

11.04b - 24 1.067,280 27 7,677 69 17 20 704,662 74 20 23 3.371 - 30 7 42
York SO 4. 1 SS,040 5 1 67 1 .1 -C 1 4.922 41 41 41 615 -10 6 1 a
Cumberland 7,99a 7j le 069,195 82 22 b.bOO (10 14 18 714.715 67 is 21 1.316 16 12 3 16
Saq.dalioc 2.38n 21 5 142.24S 13 4 930 a 2 2 GS,02S 6 2 2 1,439 fil 13 3 18

Regl"n 11 U. 211 le 642,472 16 S. 29 71 13 15 464,944 72 12 14 2,382 - 29 5 29
Lincoln 3,299 40 7 225.120 Is 6 2.:42 31 6 7 189,627 30 5 6 757 21 9 2 9
t@nox 3,236 40 7 281,591 44 7 2.6is 32 6 7 225.686 35 6 7 621 19 a 1 6
Waldo 1.676 20 4 135,761 21 3 672 a 1 2 49,631 6 1 1 1,004 60 12 2 12

Region 111 26,806 - 50 2,299;42S - 57 24,5SO 91 53 64 2,113,090 92 53 63 2.328 - 2 S 29
11ancock 10,115 39 22 728.92S 32 18 9.277 34 20 24 . 668,015 29 17 20 Ole 03 3 2 10
Washington 16.771 62 36 1.570,500 fig 39 15.261 57 33 40 1,444,275 63 36 43 1.490 9 9 3 19
Sta F] 4,009,177 - nO 4 100 8.081
t a 46,14S -:0-0 100 82 i100 13, 362.69@6

Closed Growing Axoa 1978
Pruduction Capacity Harvest
of I % 14-n Ar,n)
01 0 1 f of of of
-ounty me, ' State st:ta County Reg. state
"Ushels Total Tot., ITatil. Closed bushels Prod. Cap. Prod. Cap. Prod. Cap

Region 1 282.618 - 26 7 44 61;370 - a 2
York 50,918 91 S 1 0 14.116 287- 2 41
Cumberland IS4,490 le 14 4 @4 43,546 6 6 1
Sagadahoc 77,220 54 1 2 12 5.700 9 1 41

Rigion 11 07,528 - ja 4 27 66,411 14 2
Lincoln 35,493 lb 6 1 5 20,630 is 6 1
Knox $5.905 20 9 1 9 -37,781 14 9 1
Waldo 96.130 63 13 2 13

Region 111 186,335 5 29 270.701 11 a
l1ancock 60.110 a 3 1 9 99,57S is 5 3
Washington k26,225 a 5 3 20 171,126 12

State 46,481 100 400,482 12
r
9
13

*Api,earti to point to verY large error.
in estimatinq open growing &Fe& and its
production c@j--&clty lot York County.

Tableb-1-3.

Status of Resource Assessment and Clam Management, 1976
(From data in Goggins, 1978)

Management
T975 1976 1977 Total Town Recipr.- Depur.ti.. Catch Size crab Flat Clam
1976 1977 1978 Acres ordinance Licensing Off.icer Agreements Dig log Ugging Limits Limits Control Rotation

Kittery - 9 a 16 Yes Yes no No Yes No Yes No tic Y es
York 12 - - 12 Yes Yes No No NO tic Yes No No No NO Seasona I
Opening!;
O'ninquit 12 12 12 36 Yes Yes No No No No Yes No No Yes No -
Wel Is - - - (I NO No NO 14,@ Yes Yes No No No No 140 -
Kennebunkport 2113 - - 210 Yes Yes No NO Yes Yes Yes No No No No -
Biddeford 205 - - 205 No No No No NO No No No tic No No - co
Scarborough - - - 0 no No NO No Yes Yes No No Yes No No -
S.ut-h Nwt,lawi 15 - - is No No No No no No No No No No No -
Valm,uth - - - 0 Yes Yes 140 11. Yes No Yes NO NO No No -
cumberland - 3B - 38 Yes Yes ISO No Yes Yes Yes No No No 14. -
Yarmouth .11 - - 31 Yes Yes No No Y'! s No Yes No Yes No No Co i @ . c r va S. i
Closure
Freeport 9 114 - 123 Yes Yes No No Yes No Yes No No Yes No
Rrunswick 211 121 - 334 Yes Yes No Yes Yes No Yes Yes NO No Y.,!; -
flarpswell - - - 0 Yes Yes ISO Yes Yes No Yes Yes No No Planne,i f.,r 1971jse@v@-ys t.,)
- - - 0 Yes Yes Y es, Y"- Y Q.. Yes Yes No s: y P:
W-,.t Bath No N. S ., @. - :z t,
M ,vt 147
Ph i No No No Y, Y-@i No No No No .140

Ge.rqet... 169 169 339 Yes Yes No No Yes No Yes No 140 Yes Pla .... ed
Ne.castle - 17 17 140 No No H. y "s No No No tic No No
Damariscotta - - 6 6 No No NO NO Yes NO NO No No No 14o
Nort-h ihVen 277 - - 277 Yes Yes No No Ye . ISO Yes No NO Yen N. R I i

C,
"elimited
I@Iesboro 460 281 44 7R5 ve s Yes No No Y'! s IS,, Yes Yes No Yes tic, Sa,w as al-@-
Lincoln@ille - - 5 " I yj,:!; Yes NO No Yes No Yes No tic Yes ISO
Northport - - '20 20 S, NO No Yes Yes N. N. No NO No IM -
Stockto,L@;11K-. - - 13 6 96 No No NO Yes Yes No I I') No No No th,

-dmh@ 'Amu&,

low

Table D-1-3. (dofttinued)

1.5 T.L"l Town Reciprocal Commercial Depuration Catch Size Crab Flat Clam
1,176 :,77 ITIU A,ru@ 3rdinance Licensing officer Agreements Diyging Digging Limits Limits Control Notation Transplanting Other

U yes Yes No No Yes No Yes No No Yes No
I.- Yes No No No Yes No Yes No No No No
fsl, YUu No No Yes Yes No Yes Yes No Yes No
0 Y 's No No Yes Yes No Yes Yes No No No Survuy
plano.d in
u No, NO NO No Yes No NO No No Yes No
1,@ "'A i i., 0 Ye Yes No No yes No Yes No No yes No
:;""y 0 Yes No No No Yes No Yes No No No No Survey
planned in '79
0 Yes Yes No No Yes No Yes No NO Yes NO
1:0olk'I WO )I,,, J.") 'JUO yes Yes No No Yes No Yes No No Yes No -
It- 11 73 yet; yes No No Yes No Yes yes No No No -
11- 11.1:;1 I-L Ii I'/ Yes Yes No Ho Yes No Yes Yes 140 Y, t; No -
W.. J Yes Yes NO No yes No Yes No NO No N -
56 Yes Yes No 140 Yes No Yes Ye s No Y No Survey
planned in '79
I J:j@ l" I. 31Pj I@of 50 Yes Yes No No Yes No Yes Yes No Yes No survey
planned in '79 Eli
Wil,(-, 10,1 Yes Yes No NO Yes No yes No No No No
0 Yes Ye s No No yes no Yes No No Yes No Survey
planned in '79
L 1,, i d, 58L Yes Yes No Yes Yes No Yes Yes No Ycs No
11- , inqt-, 0 Yes Yes NO N C, Yes No Yes No No Yes 14LI Survey
planned in '79
j., @jHJ Wl Yes Yes no no Yes No Yes yes No Yes No -
V@ - 245 Yes Yes No 140 Yet; No Yes Yes No Yes No -
I@i - 123 Yes Yes No NO Y,ts No Yes No No No No -
tpl - s2fl Yes Yes No 140 y ". No Yes No No Yes No -
Ve 9 No US no No Yes N. -
Yeg N6 wl@ yes No you flu No No -
Yes No No No
o U. Y L, ". 0 No No No NO
ife'CoLt 22L, 226 No No No rill yes N S, No No yes No Survey
0 yes Yes No NO yl,s No Ye planned in '79
L i nq 140 140 No No
No 11. Yes NO No
300 No No yes No NO NO 14.
,,,,,broko 121 427 Yes No Ht, Iju Y,j. No No No No
9 9 yes Y s No Yes Yes NO Yes Yes No Surv.Y
i-,;rry No Yes No No No
- 0 Y Yes No yes Yes pl,, .... Od in 179
's Y No rill Y es No Yes 140 NO HO No con@,rvjLion
Clos.rl,
L*uL I.r 295 YL

230

Table D-1-4

Suirmary of Table D-1-3

No. of towns Area surveyed
taking some % of Total
steps toward open growing area
management Acres

Region 1 16 1,028 14.8%

Region 11 8 1,544 28.5

Region 111 31 6,097 25.3

Totals 55 8,669 23.8

Total towns having
clam resources 101

Total towns having
taken no action 46

low 'low AM 'low

Table D-1-5.

Processing of Clams Through Depuration Plants

1974-1978

(DMR Unpublished Data)

TOTAL FOR OF TOTAL
YEAR WASHINGTON RANCOCK WALDO KNOX LINCOLN SAGADAHOC CUMBERLAND YORK YEAR LANDINGS
Bushels Bushels Bushels Bushels Bushels Bushels Bushels Bushels Bushels

1974 47 2,227 7,069 2,136 11,479 2. k)

1975 11,025 2,121 13,146 3.0

1976 14,530 1,448 15,978 3.1

1977 -- -- -- -- 5,056 9,322 710 15,088 2.9

1978 2,242 163 13 2,435 4,794 4,533 810 14,990 3.7

2,242 210 2,240 2,435 9,850 46,479 7,225 70,681

232

Table D-1-6.

Commercial Clam Areas with Unrestricted

Opening Due to Municipal and Private

Pollution Abatement, 1970-1978

(Adapted from Winters, 1979)

Value
Reclaimed Area Productivity (Standing Crop
(Acres) (Total bushels) $22 per bu.)

Region 1 753 78,207 $1,720,554
York 54 3,947 86,834
Cumberland 699 74,260 1,633,720
Sagadahoc

Region 11 404 45,690 11005,180
Lincoln 326 39,120 860,640
Knox 78 6,570 144,540
Waldo

Region 111 420 32,720 719,840
Hancock 420 32,720 719,840
Washington

Totals 1577 156,617 3,445,574

233

Table D-1-7.

Commercial Clam Areas with Conditional (Seasonal)

Opening Due to Municipal and Private

Pollution Abatement, 1970-1978

(Adapted from Winters, 1979)

Value
Reclaimed Area Productivity (Standing Crop
(Acres) (Total bushels) $22 Rer bu.)
It Region 1 289 21,810 $479,820
York 20 1,000 22,000
Cumberland 194 13,160 292,820
Sagadahoc 75 7,500 165,000

Region Il 144 4,200 921400
IF Lincoln 104 2,600 57,200
Knox 40 1,600 35,200
Waldo

Region 111 212 11,988 263,736
Hancock 212 11,988 263,736
Washington

Totals 645 37,998 835,956_

234

Table D-1-8.

Commercial Clam Areas Opened to

Depuration Digging Due to Municipal

and Private Pollution Abatement, 1970-1978

(Adapted from Winters, 1979)

Value
Reclaimed Area Productivity (Standing Crop
(Acres) (Total bushels) S15 pex bu.)

Region 1 785 55,830 837,450
York 10 750 11,250
Cumberland 331 19,860 297,900
Sagadahoc 444 35,220 528,300

Region 11 570 47,734 716,010
Lincoln
Knox
Waldo 570 47,73 4 716,010

Region 111 481 37,550 563,250
Hancock 31 1,550 23,250
Washington 450 36,000 540,000

Totals 1,836 141,114 2,116,710

235

Table D-1-9.

Number of Commercial Shellfish Licenses, 1942 1978

(DmR unpublished Data)

1942 1,292 1961 1,572
1943 1,260 1962 .1,505
1944 1,487 1963 1,623
1945 1,501 1964
1946 1,837 1965 1,613
1947 2,474 1966 1,376
1948 3,326 1967 1,470
1949 2,823 1968 1,194
1950 2,281 1969 2,226
1951 2,006 1970 2,742
1952 2,394 1971 3,175
1953 2,341 1972 4,143
1954 2,553 1973 5,927
1955 2,239 1974 5,493
1956 2,100 1975 5,181
1957 1,976 1976 4,562
1958 1,623 1977 5,291
1959 1,554 1978 4,287
1960 1,553

236

Table D-1-10.

Fishing Effort of Clam Diggers - 1973

5,933 total licenses,,3,147 (53%) reporting

(From Goggins, 1975)

Bushels Dug No. of
Per Day Diggers %

0.1 - 1.0 1,269 40
1.1 - 2.0 1,320 42
2.1 - 3.0 432 14
3.1 - 4.0 81 3
> 4.0 45 1

Months No. of
Dug Diggers %

0-1 644 20
1-2 676 21
3-5 997 32
6-8 530 17
9-11 117 4
183 6
12

237

Table D-1-11.

Extrapolation of Table 10 Data to Amounts

of Clams Harvested

Bushels Dug No. of Total Bushels
Per Day Diggers Dug Per Day

0.5 1,269 634
1.5 1,320 1,980
2.5 432 1,080
3.5 81 284
5.0 45 225
4.1203 bu.

Total Bushels
No. of % of Diggers Total Bushels Dug During
Days Dug Working Dug Per Day Working Period

10 20 4,203 8,406
30 21 4,203 26,479
80 32 4,203 107,597
140 17 4,203 100,031
200 4 4,203 33,624
240 6 4,203 60,523
336,660 bu.

*Using midpoint of each class.
"Using midpoint of each class and based on 20 working days per month.

Table D-1-12

Age-Profile of Commercial Shellfishermen 1974
(From Goggins, 1975)

Age-Groups: Percentage of Total

Number <18 18-19 20-24 25--29 30-34 35-39 40-44 45-49 50-54 55-64 >64

33 9.1 9.1 21.2 9.1 12.1 15.2 9.1 - 6.1 3.0 6.1 York
406 16.7 15.3 12.6 11.1 9.1 9.4 6.4 3.4 7. 2.5 ICumberland

121 6.6 3.3 9.1 16.5 11.6 15.2 10.7 8.3 7.4 8.3 3.3 Sagadahoc

521 15.4 7.3 15.5 15.4 11.3 9.2 8.3 5.6 .3.5 6.7 1.9 Lincoln

566 17.7 6.7 15.5 15.7 10.2 9.5 6.5 5.3 5.3 5.1 2.3 Knox
- CO
173 12.1 1.7 14.5 15.-0 10.4 12.1 7.5 7.5 7.5 6.9 4.6 Wa ldo

2152 20.2 5.0 14.6 14.7 10.1 .7.7 7.4 6.0 4.7 6.3 3.3 Hancock

1192 12.8 4.9 12.8 11.7 11.7 10.2 8.4 8.2 6.8 9.3 3.0 Washington

560 14.1 7.1 14.3 13.2 11.3 10.7 9.6 6.4 4.6 7.5 2.9 Region I

1260 16.0 6.3 15.1 16.1 10.7 9.8 7.4 5.7 4.8 6.0 2.4 Region I

3344 17.5 5.0 14.0 13.6 10.7 8.6 7.8 6.8 5.5 7.4 3.2 Region III

5333 16.4 5.4 14.5 14.2 10.8 9.1 7.9 6.5 5.2 7.1 2.9 State

1,00 Va *w to Ow I" VO oft, 00, w

owl ip-11111 ota) 40

uj
:) 10.0-
0

9.0-
0 -1 11itII
CA < 8.0-
z 6
.0
_-Jj 70- POUNDS

6.0-

50-
z
0 4.0-
a.
U- ul
o 2 3.0-

cn LL
z o 2.0-
0
_j DOLLARS
_j 1.0-
0.0, V
1680 1890 1900 1910 1920 1930 1940 1@50 1960 1970 1980

FIGURE D-1-1.
TOTAL LANDINGS OF SOFT-SHELL CLAMS IN MAINE 1887 - 1978
(DMR UNPUBLISHED DATA)

700 690 680 670
NB

4
0
5
WASHINGTON

l:'.','HANCOCK

WALDO

KNOX. L-3

SAGADAHOC.,-." LINCO.:N . .....
0-
44
REGION -M
CUMBERLAND,

REGION IE
YORK--,

REGION I
43 N:
700 69 0 68 0 670

FIGURE D-1-2,'

1.30
DOLLARS
Ld
1.20
0
C-) W 1.10
u- Z
0 w 10 - 1.00
U

z 9 - -0.90

POUNDS
8 - 0.80
z
7 - -0.70
0
a.
U)
6 - -0.60 cr-
w
z (L
0 5 - 0.50
(L

u- w
02 4 - LICENSES -0-40
(n u.
z 0 3 - -0.30 0
0
_J 2 - -4k, -0.20

0.10
0., 1010
Iw 045 1950 1955 1960 1965 1970 1975 1980

FIGURE D-1-3.
ANNUAL LANDINGS OF SOFTSHELL CLAMS , AVERAGE ANNUAL PRICE PER POUND
OF MEATS . AND ANNUAL TOTAL COMMERCIAL SHELLFISH LICENSES 1942 -1978
(DMR UNPUBLISHED DATA)

W 12

w
U 8

w
CL 6
NJ

AGE CLASSES

FIGURE D-1-4.
AGE PROFILE OF 5,333 COMMERCIAL SHELLFISHERMEN , 1974
(BASED ON DATA FROM GOGGINS. 1975)

OW no 40 low to 404 40b@ @pw Affia" 40* ow to 403, lft@ 40

243

ELEMENT D-2: A CHARACTERIZATION OF

THE NORTHERN SHRIMP FISHERY

OF MAINE..

Alden P. Stickney

244

I* GEOGRAPHICAL OCCURRENCE

The northern shrimp (PandaZus boreaZis), sometimes called the pink

shrimp, is circumboreal in distribution. Populations occur in the

Barent's Sea, Norwegian Sea, North Sea; off the coasts of Iceland,

Greenland and Labrador; in the Gulf of St. Law re nce and the Gulf of

Maine. On the Pacific side, the species is found in the Gulf of Alaska,

the Bering Sea and the Sea of Okhotsk. The southernmost limit is in the

Gulf of Maine (Lat. 410 N); elsewhere none occur south of Lat. 45 0N

(Haynes and Wigley 1969). Although the northern shrimp requires

relatively cold water-not above about 120C (Allen 1959)-it does not

reproduce well and grows very slowly at near freezing temperatures

(Squires 1968; Horsted and Smidt 1965), hence it is not common in

Arctic waters (Haynes and Wigley 1969).

In the Gulf of Maine, the densest populations of P. boreaZis are

in the western, or inner, part (Fig. D-2-1) with localized concentrations

near Jeffrey's Ledge, Wilkinson Basin, Cashes Ledge and Mt. Desert Rock.

These population centers were described by Haynes. and Wigley (1969) on

the basis of surveys made during the period 1963-1965. Other centers

may exist and all may change from time to time. Few shrimp were taken

.in these surveys in the eastern part of the Gulf and near the southern

end of Nova Scotia, indicating a break in distribution from the more

northern populations.

P. bareaZis occurs in depths from 20-900 meters (Hjort and Ruud

1938). A complete discussion of the distribution of the species within

245

the Gulf of Maine requires an account of its life history

because seasonal migrations associated with certain developmental

periods create marked changes in distribution patterns (Apollonio and

Dunton 1969). Briefly, the eggs hatch in late winter, the larvae are

pelagic until metamorphosis sometime in mid-summer and the young shrimp,

now bottom dwellers remain juveniles until the end of their second

summer. At the end of the third summer they become mature males. For

a brief period during the third winter and following spring the sex

changes and the animals are in an intermediate sexual condition called

transitional. They become fully female at the end of the fourth summer

and lay eggs for the first time. These eggs are impregnated by the

males of the up-coming year class...Females sometimes live to spawn once

or even twice more so that the population of mature females may contain

several age groups.

Migrations between the shallow waters near shore and the deeper

waters offshore occur annually but involve different age groups at

different times of the year. After extruding their eggs in August

through September, the ovigerous females remain in deep water until

December at which time they migrate inshore where they stay until the

eggs hatch in February and March. After the eggs are hatched the

spent-females return to deeper water. The pelagic larval shrimp and

the juveniles remain in inshore waters, but when they approach maturity

as males they migrate offshore in November and December. The

distribution of the various life history stages resulting from these

246

movements is summarized in Figure D-2-2.

Ii. AVAILABILITY

The shrimp population varies in its av ailability to the fishery,

reflecting several kinds of natural and artificial restrai nts,

Artifically imposed legal restrictions may limit the times or places

fished, the quantities captured and the effectiveness of the gear used.

Economic factors determine whether the fishing is worth the investment

in gear and effort, and of course weather conditions play a big part in

the amount of fishing that can be done. The major factors, however, in

determining the availability of the shrimp are biological: the abundance

and distribution of the shrimp themselves.

1. Abundance. Historically, shrimp have been plentiful in the

Gulf of Maine, at least intermittently. Rathbun (1884) stated that at

that time shrimp were abundant though not extensively fished because of

thelimitations; of contemporary gear for fishing in deep water. Although

the otter trawl came into use about 1905 in the Gulf of Maine, few

shrimp were taken, probably because the meshes of the nets used (for

groundfish) were too large (Scattergood 1952). Birdseye (1928) records

small quantities of shrimp being landed in 1927 and some years earlier.

In 1927 and 1928 the General Sea Foods Corporation sponsored several

exploratory cruises using commercial vessels and gear to make assessments

of the shrimp populations in the Gulf of Maine,off the Maine and New

Hampshire coasts. Catches as high as 2000-3000 pounds a day were taken

by one vessel between Cape Ann and Boone Isla nd in January 1928.

247

Although the evidence indicated that shrimp were widely abundant in the

Gulf of Maine, the company concluded that more study and effort were

needed before a dependable fishery could be undertaken. Hjort and Ruud

(1938) investigated the shrimp populations in the Gulf of Maine with

the research vessel "Atlantis" in 1936, so that they might compare

these populations with those in the North Sea and the Skagerak. Their

conclusion was that the abundance of shrimp in the Gulf of Maine, based

on the analysis of the samples by Bigelow and Schroeder (1939), compared

favorably with that in Norway and Sweden.

Not until 1938 was a purposeful fishery for shrimp undertaken from

which reliable catch statistics could be obtained. From 1938 to 1979,

however, catch data are available from which estimates can be made of

the relative abundance of shrimp (Table D-2-1 and Fig. D-2-3). This span

of about 40 years can be divided into two major periods of abundance-one

where effort was small and perhaps tentative and catches were modest,

and a second following a four year period of scarcity which was

characterized by increasing abundance and effort to culminate in the

peak landings of over 10 thousand metric tons in 1969.

Formany years the major producing areas were along the coast of

Maine (Fig. D-2-4), off Cape Elizabeth, Cape Small, Sheepscot Bay and

Pemaquid Point (Scattergood 1952). During the second phase of the

fishery (1958 to the present time) a considerable expansion in the areas

and seasons fished took place. Earlier, the coastal fishery had been a

winter fishery because of the concentration of ovigerous females there

248

at that time of year. Later a summer fishery developed on offshore areas

such as Jeffreys Basin, Stellwagen Bank, or Scantum Basin. Although the

vessels fishing these populations were mainly from Gloucester, Massachusetts

their catches were frequently landed in Maine ports.

Since 1964 the shrimp and the shrimp fishery have been studied far

more intensively than in previous years; for that reason data are

available to provide a much better assessment of the shrimp population

than was possible during the earlier years of the fishery. Abundance

indices in terms of catch per day fished have been calculated for

different size classes of fishing vessels. These data (Fig. D-2-5) give

a better index of abundance than do landings by themselves. They show,

however, the same general decline in abundance from 1969 on as do the

landings. Similarly, the results of research cruises, both by the State
of Maine and by the National Marine Fisheries Service, show 'a decline in

abundance during that period. Estimated stock size (Northern Shrimp

Scientific Committee 1979) dwindled from 27 thousand metric tons in 1969

to less than a thousand in 1979.

Unfortunately no comparable data are available for the period 1938-

1953. The landings were, of course, several orders of magnitude smaller

during that period, but the effort was much lower as well. While over

300 boats engaged in the fishery between 1969 and 1975, the greatest

number fishing during the earlier period was 31.. Between 1969 and 1977

the catch per day per vessel ranged from 0.73 to 2.57 metric tons. In

1938, a few incidental figures given by Scattergood (1952) for individual

249

vessels, 0.75 and 0.56 metric tons per day, give an indication of

abundance in that period. Although the abundance of shrimp in the

earlier period may not have been as great as in the later period, it

was probably much higher than landings would indicate.

Between the early and recent periods there occurred a four-year

hiatus when virtually no shrimp were landed despite persistent attempts

to find them; and as recent statistics show, there is at the time of

this writing Another period of low abundance. Thus in the past 40

years the shrimp populations have undergone two major cycles of

abundance and scarcity. The causes of these cycles are not known

with certainty but may include several factors.

The first of these is the ability of the species to reproduce

itself, including the fecundity of the parents, and the survival of eggs

and larvae. Each female shrimp produces from 800 to 3400 eggs,

depending on her age and size (Haynes and Wigley 1969). Egg mortality

and its causes have been discussed by Haynes and Wigley (1969);

Apollonio and Dunton (1969); Stickney and Perkins (1977, 1979) and can

occur through accident, parasitism and disease and unfavorable conditions.

Stickney and Perkins reported that the incidence of parasitized (non-

viable) eggs averaged 5% of the egg mass in 1974-75 and about 1% in 1978-

79; percentages of females infected were 92% in 1974-75 and 55% in 1978-

79. Haynes and Wigley (1969) found 74% of a sample collected prior to

1865 infected, with the average infection about 1% of the egg mass.

These percentages do not include eggs that were killed and disintegrated

250

prior to the observation, nor the additional ones that would have been

killed if the shrimp had remained in the habitat. Egg losses from all

causes may be high. Stickney and Perkins (1979), by comparing the

egg numbers carried by shrimp just pr ior to hatching with an expected

number derived from a size-fecundity curve, found that in 1974, for

instance, the numbers of eggs at hatching time were 24% lower than they

should have been. Substantial egg losses from oviqerous PandaZus boreaZis

have been reported in Alaskan waters (Patrick Holmes, Alaska Dept. of Fish

and Game, personal communication); in laboratory experiments, Stickney

and Perkins (1975, unpublished report) observed egg losses of up to 25%

during incubation. Even higher mortality occurs after the eggs hatch

during the pelagic larval period.

No data are available which establish the mortality during this

period with certainty, but larval surveys by Apollonio and Dunton (1969)

and by Stickney and Perkins (1979) @how attrition rates of larvae

abundance ranging from 99.9999% to one hundred times that amount during

the period of the 6 larval stages. The attrition is not necessarily nor

entirely due to mortality, but a very high mortality rate is strongly

suggested. The mortality from larva to maturity was estimated by

Apollonio and Dunton 11969) as about 99%. Asevere mortality befalls

the adult females after the first reproductive period and only about

12% of the females survive to spawn a second time (Haynes and Wigley

1969).

The causes of natural mortality include both biotic and abiotic

251

factors; some of these are known while others are either merely assumed

or are unknown. Parasitism and disease are probably responsible for

some losses in all stages of the life history of the shrimp. The

11white egg" parasite described by Stickney (1978) and responsible for

the so-called "non-viable" eggs mentioned by several authors kills large

numbers of eggs and other egg parasites (Apollonio and Dunton 1969)

undoubtedly kill many also. Parasites of juvenile and adult shrimp

have also been described, including a bopyrid isopod (Hjort and Ruud

1938; Horsted and Smidt 1956) and a fungus (Uzmann and Haynes 1968;

Apollonio and Dunton 1969; Rinaldo and Yevich 1968). The extent to

which any of these parasites contributes to natural mortality in the

Gulf of Maine is not known.

The principalbiotic causes of natural mortality, however, are more

likely predation, competition or inadequate food supply-the last named

@being more of a hazard to larvae than to adults. Bottom fish of many

kinds of prey on adult and juvenile shrimp, some quite heavily. Maurer

and Bowman (1975) found that 31 out of 80 species studied from Nova

Scotia to Cape Hatteras had eaten pandalid shrimp and for size of

these species pandalids made up more than 10% by weight of the food

eaten. These six species were the barn door skate, the smooth skate,

the red hake, the wrymouth, the weakfish and the four-spot flounder.

The last two are not common in the Gulf, however. Many species abundant

in the Gulf of Maine might have appeared more significant as predators

of shrimp had the study of Maurer and Bowman included only that region.

252

The pelagic larvae of PandaZus spp. are undoubtedly consumed by

large numbers of planktonic predators such as pelagic fish, ctenophores,

or chaetognaths. The larvae themselves feed on diatoms and small

zooplankton, the abundance of which is apt to be low in winter, and

starvation could also be a major cause for larval mortality.

Among the abiotic causes of mortality, the most important is

probably temperature (Dow 1979). PandaZus borealis in the Gulf of

Maine are living at the southernmost limit of their range and where

temperatures may reach detrimentally high levels. Temperature can

affect survival at all stages, directly or indirectly, although seldom

have deep water temperatures been recorded in the Gulf that are high

enough to kill the shrimp directly. Adverse temperatures may affect

egg development, behavior, physiology, or incidence of parasites

(Stickney and Perkins 1977, 1979; Apollonio and Dunton 1969) in such

a way as to increase mortality or reduce reproductive potential.

Dow (1973, 1979) has shown evidence that the abundance of Panadazus

borealis in the Gulf of Maine is inversely correlated with water

temperature. During periods of higher water temperature the abundance

of shrimp decreases. A correlation coefficient of 0.66 was given by

Dow (1973) between the mean annual water temperature for each year

recorded at Boothbay Harbor, Maine, and the landings of shrimp four

years later. This relationship suggests the effect of temperature is

most strongly felt on the.very early developmental stages since most of

the shrimp catch consisted of 4-year-old females.

253

The correlation between temperature and shrimp landings has been

criticized for not adequately taking into account the effect of

increasing effort, which between 1967 and 1975 has accompanied the

rising temperatures and declining catches. Dr. Steve Clark, of the

National Marine Fisheries Service (personal commun ication) showed by

using partial correlation analysis that, at least during this period,

the correlation coefficient between effort and abundance independent

of temperature was higher (r = -.46) than that between temperature and

abundance independent of effort (r = -.11). This comparison, however,

deals only with a minor part (9 years) of the larger temperature-abundance

cycle, which seems, on the whole, to show a convincing relationship.

Moreover, in all discussions of temperature cycles, the data used to

support or refute the argument have been surface temperatures recorded

at Boothbay Harbor. While these do show a relationship in annual trends

to offshore bottom temperaturesf they are obviously not the temperatures

to which the shrimp are exposed. Unfortunately, the records for the latter

are far less complete than the Boothbay Harbor surface temperature

record (Fig. D-2-7). In this figure, the mean annual surface water

temperatures are shown from 1940 to 1978. In addition, November offshore

bottom temperatures, collected by the National Marine Fisheries Service

groundfish survey cruises from 1963 to 1978, are also indicated. A

third group of temperatures are shown, derived from the mean Boothbay

Harbor surface temperatures for the month of August. The November off-

shore bottom temperatures are correlated closely with the August inshore

254

surface temperatures (r = .92) and can be estimated by the relationship

Y = -13.27 + 1.313 X. The month of November is useful as an index of

incubation temperature because by November all eggs have been extruded

but massive inshore migration has not started yet.

Probably the greatest toll on adult shrimp is taken by the fishery.

A summary of the estimated population parameters related to stock size

and mortality for the ten year period 1968-1977 is given in Yable D-2-2

(Northern Shrimp Scientific Committee 1979). The instantaneous fishing

mortalities listed in the first column are equivalent to annual fishing

mortality rates ranging fr om 51% in 1968 to 86% in 1977. These rates

were computed from Maine survey data and an instantaneous natural

mortality of 0.25 assumed.

2. Distribution. The second major factor that determines avail-

ability is where the shrimp are to be found-either as a result of

seasonal movements or their general long term distribution. Until the

development of the otter trawl just after the turn of the century, northern

shrimp were for all practical purposes unavailable because their habitat

was too deep to fish (Rathbun 1884; Scattergood 1952). Now, no known

populations are.completely unavailable because of their location. Although

even modern fishing gear is of limited effectiveness where the shrimp lie

close to or among rocky areas of the bottom, and fishermen tend to avoid

these areas because of the danger of losing gear, recent improvements

in sonar equipment have enabled fishermen to fish closer to ledges than

has been possible in the past.

255

Even populations readily accessible to gear may be available only

to vessels large enough to go after them, when they occur a great

distance from port. Smaller boats are more apt to limit their fishing

to winter inshore populations. Seasonal migrations also affect avail-

ability. When the egg-bearing females migrate shoreward in the

winter, they become more available not only because of increased

proximity to the shore, but also because they tend to be more concen-

trated in distribution.

It is possible also that winter temperatures influence availability

through their effect on the duration of egg incubation. Stickney and

Perkins (1977) found that a 20C difference in mean temperature (in vitro)

could increase or decrease the incubation time by a month. Since the.

spent females leave the inshore fishing areas after the eggs have hatched,

an additional few weeks of availability to inshore fishing might be

assured by a cold winter.

Short term variations in availability may result from unfavorable

weather preventing long trips to sea. The winter fishery in particular

is subject to hazards of high winds, heavy seas and icing of boats and

gear, and the number of days when fishing if possible is limited

accordingly.

3. Problems relating to availability. There is little question

that not only have stocks been declining drastically over the past ten

years, but that excessive fishing pressure has been a major cause.

There is also little doubt that the species exhibits severe fluctuations

256

in abundance as a result of natural but as yet unknown,causes related

among other things to temperature. Similar fluctuations are known for

many other species, even those which are not exploited. The critical

question, therefore, is the relative contribution of the two forces,

fishing and environment, to the changes in stock size. Can the stock

size, yield, or any other population parameter be optimized by regulating

fishing pressure, or are they so dominated by uncontrollable

environmental forces that regulation is futile? Both of these positions

have been defended by knowledgeable people with long experience in the

study of PandaZus boreaZis so that the resolution of the problem may

have to await new information, or be based on other than biological

considerations.

III. HARVESTING

1. The fishermen. The average Maine fisherman is about 42 years

old, and has about 10 years of formal education. Actually, however, all

age groups are represented about equally in the fishing community and

more than 40% have completed high school. Fishing is likely to be a

traditional family enterprise, younger men following the steps of their

fathers in the trade. Many shrimp fishermen started in the business

fishing for other species-groundfish, herring or lobsters and continue

to do so for much of the year.

2. The vessels and gear. The first boats in the shrimp fishery

were small side trawlers engaged during the summer in the whiting fishery.

257

Later, numerous lobster boats of various sizes from 28 to 40 feet

joined the fleet. These smaller boats were modified in varying

degrees, some with the addition of gallows frames, winches or booms,

some with little more modification than using the pot hauler to tow a

small net. The side trawlers, from 45 to 75 feet, already rigged for

towing an otter trawl needed little modification. A few of the larger

boats were purchased from southern waters where they had been engaged

in the Gulf of Mexico shrimp fishery. Some of these were double

rigged, although according to Bruce (1971) this gear was removed and

the rig changed to side or stern trawler. A few boats, the largest

being the 59 foot "Amy Jo" were built in Maine especially for the

shrimp fishery. Others of more modest size were built along the lines

of a lobster boat.

The number of vessels operating from Maine ports increased from

29 in 1964 to over 300 in 1974 (Table D-2-3). Until 1968, more than

half of the fleet were the larger trawlers, but from 1969 on, there

were about twice as many of the smaller lobster boat conversions than

the trawlers.

The standard gear used by the larger vessels was the 50-70 trawl,

having a 50 foot head rope and a 70 foot foot rope, the latter being

either chain or roller gear, depending on the kind of bottom on which

they were used. The simple chain footrope, used commonly on the trawls

of the smaller boats limited their fishing to relatively smooth bottoms.

The doors (otter boards) of the large trawls were rectangular from 5 to

258

7 feet long and weighed 350 to 800 pounds. Smaller vessels carried

smaller gear of various designs, depending on the tastes and experience

of the individual fishermen.

The net itself was of nylon or polypropylene twine with 2"

(stretched) mesh in the wings, square and belly of the trawl, 1-3/4"

to 1-7/11" mesh in the cod end, Also used occasionally by the larger

trawlers were the semi-ballpon trawl and the 4-seam trawl.

In the last few years of the fishery, the trap was introduced.

Similar in function to a lobster trap, the typical shrimp trap was made

of wire mesh in the form of a rectanular' box with a slit in the top.

It was ballasted and buoyed in much the same way as a lobster trap and

baited with fish. Although the contribution from traps to the total

shrimp landings was very small (not over 3%), the method nevertheless

had several advantages. Traps can be fished on irregular bottoms not

suitable for trawling, trap caught shrimp are likely to be in better

condition when landed, hence of potentially more value; and the method

is suitable for a small one man operation with a minimum investment. A

good harvest for the trap fishery might-average 200-300 pounds per trap

per season (Bruce 1971).

3. Fishing practices. Typically, a trip to the fishing grounds

and return is made in one day. Most of the localities fished, especially

in the inshore winter fishery are not more than 2-3 hours steaming from

ports, so that a boat can leave early in the morning and return in the

late afternoon before dark. Tows are made for 1-2 hours before hauling

259

back. Typical catches might be 100-300 pounds of shrimp per tow during

periods of abundance.

Fishing boats operate from many ports along the coast, a few of the

more important being Portland, Boothbay Harbor, New Harbor, Rockland,

Vinalhaven, and Southwest Harbor.

4. Effects of economic conditions on harvesting. When the fishery

for northern (pandalid) shrimp first began in the late 30's, the

consuming public was generally unfamiliar with the product. Its size

and color differed from the southern shrimp usually found in the market.

For several years,.therefore, the demand for the northern shrimp was low

and undependable (Scattergood 1952) and less than maximum fishing effort

reflected this. The price, about $.07 a pound (Fig. D-2-3), was hardly

an incentive. To improve demand, the Maine Department of Sea and Shore

Fisheries (now Department of Marine Resources) undertook the promotion

of northern shrimp. Eventually, in 1949, the price reached $.20 a pound

but by that time the availability of shrimp was decreasing, and ef fort

that was once only sufficient to Tneet the demand was increased in an

effort to keep up with it. Supply rather than demand was determining

the price.

Withe the reappearance of shrimp in 1958, a waiting market offered

a premium price of $.40 a pound. This, plus an apparently increasing

supply, stimulated the expansion of the fishery, investment in which

increased tenfold in the following decade. But with the ever increasing

availability of shrimp, there came an inevitable saturation of the domestic

260

market and a decrease in price. Fortunately for the industry, however,

a decline in the supply of shrimp in northern European waters which took

place in the late 60's resulted in a new and fortuitous overseas market,

especially in Scandinavian countries. This development had the effect

of boosting prices and encouraging additional effort. A decline in

the availability of certain popular food fish (e.g., haddock) at the

time also tempted fishermen to turn to fishing shrimp. A healthy,

profitable fishery continued for about five years until 1976 when signs

of declining abundance were clear. This trend has continued until the

present, so that although the price has reached $.70 a pound, so few

shrimp are left that virtually no fishing for them is carried on in

Maine.

5. Legal constraints on fishing. Legal constraints have been

minimal. virtually no restrictions were imposed prior to 1973 with

the exception of the application to the shrimp fishery of certain

closed area regulations for trawling in general and the requirements of

a fishing license. But because of concern over declining stocks a

state-federal conservation program was initiated in 1972 by the National

Marine Fisheries Service and the states of Massachusetts, New Hampshire

and Maine. Several regulatory schemes were discussed, including

minimum size limits on the shrimp in the catch, closed seasons and gear

limitations. Of these tentative schemes, all were abandoned except the

last and a study to establish a minimum mesh size was begun. In October

1973, an interim minimum mesh size of 1.5 inches (stretched) was adopted

261

by all three states. As a result of the study the minimum mesh size of

1.75 inches (stretched) was ultimately adopted in 1975. This mesh

opening was designed to permit the retention of shrimp larger than 4.7

inches, and permit the escape of 75% of the mature males. A closed

season was implemented from July 5 to September 27 in 1975, but this

probably had little effect on the Maine fishery which is predominantly

a winter fishery. A closure of the fishery in the winter of 1977-78 did

have a traumatic effect and in response to pressure from the industry

this closure was not repeated the following winter. By that time,

however, the reduced supply had made fishing a doubtful risk, anyway.

One legal constraint on fishing generally that applies to the

shrimp fishery, although the extent to which its influence is felt is

uncertain, is the federal law that requires vessels over 5 tons used

for coastal trades (including fishing) to be built in the United States.

This limits the choices that a fisherman may have when buying a boat

in matters of design, construction, size, etc. vs. cost. Another

federal law which levies substantial duties on the imported fishing gear

(much of the better gear is imported) adds to the fisherman's costs.

It is significant in this respect that while duties on fishing gear have

been increasing, the duties on imported fish and fish products have not.

Thus federal tax laws seem to hinder the American fisherman while helping

his foreign competition (Henry and Halperin 1970).

6. Problems in harvesting. When shrimp are plentiful there are,

from the point of view of the fisherman,no major problems in harvesting.

262

From the biological point of view there are several problems. When the

egg-bearing females migrate shoreward in the winter they present the

fisherman with an ideal opportunity: high concentrations only a short

distance from port., It is obvious why the Maine fishery has been

pr imarily a winter fishery since its inception. There are other reasons

why the egg-bearing females are desired-they do not shed (molt

the egg carrying period and hence are firmer and more easily handled

without damage; furthermore the load of eggs adds to the weight of any

given number of shrimp.

Unfortunately, the practice of fishing on a spawning population is

not generally viewed as conducive to conservation. Even where such

fishing is customary (e.g., the salmon fishery) some escapement is

allowed for in managing the fishery. This is not the case in harvesting

the shrimp, where fishing pressure is continuous from the time the

shrimp arrive in coastal waters to the time the survivors leave.

Because the larvae are extremely vulnerable it is imperative that as

many eggs as possible be permitted to hatch in order that adequate

recruitment to the population be assured. The management of the shrimp

fishery in some countries (e.g., Greenland) is designed to permit the

escapement of at least half of the ovigerous females.

Another problem related to the harvesting of shrimp is the by-catch

of finfish, which may even exceed the shrimp catch. In the 1975 gear

evaluation studies, for instance, a total of 30 thousand pounds of shrimp

were taken, but along with these were taken 40 thousand pounds of cod,

263

whiting, hake and flatfish. Often this by-catch consists of small, non-

marketable individuals which are discarded and thus are a loss to the

ultimate yield of those species.

A third, and probably the most serious problem, is related to

availability. When shrimp become scarce, it is necessary for the

fishermen to shift to other species. Usually this involves costly and

time consuming changes in vessel rig or gear. Many fishermen, for

this reason or others, cannot afford to shift and are compelled to go

out of business. In a questionnaire sent to Maine fishermen (Dunham

and Mueller 1976) eight individuals (15% of respondents) replied that

they would have to quit fishing if the shrimp fishery collapsed.

It would be highly desirable, therefore, if new fishing boats

were designed and built with as much flexibility as possible for

multiple-fishery use. Such vessels can be built and have been used,

especially on the Pacific coast (Captiva,1971). Shifts from shrimp

fishing to lobstering, groundfishing or herring seining could then be

made rapidly and with little additional expense.

IV. PROCESSING

During the prime of the shrimp fishery (1968 through the early 70's),

there were over 20 shrimp processing plants operating in Maine in 16

localities (Fig. D-2-4, Table D-2-5); by 1976 there were 7. At the

present time there is only one, in Portland.

1. Methods. Shrimp are processed in any of several ways for the

market. The processing techniques have largely been adopted from those

264

of southern U,S. shrimp industry or of Scandinavian countries. Northern

shrimp are marketed with the following kinds and degrees of processing:

a. Fresh, whole

b. Cooked, whole

C. Cooked, peeled

d. Cooked, peeled and frozen

e. Raw, peeled and frozen

f. Peeled and canned

a. Fresh, whole sh rimp. Marketing shrimp in this condition

requires the least processing, but the markets must be readily

accessible to minimize deterioration. The catch is first culled to

remove unwanted trash species, broken shrimp and debris, then washed.

Since this process can be time consuming, a "cleaner" catch is more

desirable and trap caught shrimp may be favored for this market.

b. Cooked, whole. This process became prevalent with the expansion

of the European market. Although more shrimp can be handled faster

in shore based automated processing lines, it was found expedient for

about a third of the catch to cook the shrimp on board the fishing

vessels before landing them. This procedure was adopted because the

Scandinavian market re quired the shrimp to be cooked very shortly after

capture so that the curl of the tail would be retained (Bureau of

Commercial Fisheries, 1969).

The process of cooking requires culling and washing as with fresh

shrimp. The clean catch is then boiled 3 to 5 minutes in a brine made

265

up of sea water with one part in eight or ten of added salt. After

landing, the cooked shrimp are sorted carefully to select intact and

properly curled individuals and packed whole in boxes. Usually the

eggs, if present, are left on. Most of these shrimp are shipped as

rapidly as possible under refrigeration, but some may be frozen in

polyethylene bags for storage. At one time cooked shrimp for the

Swedish market were artificially colored with a red dye, the use of

which has now been discontinued (Savoie 1971).

c. Cooked and peeled. Removal of eggs from shrimp is a time

consuming process, so that many cooked shrimp for the domestic market

are peeled, thus removing both eggs and shell. The meats are sold

refrigerated or frozen. Peeling of cooked shrimp is often done by

hand.

d. Cooked, peeled and frozen. when cooked meats are to be frozen,

they may either be packaged dry in plastic or cardboard containers or

frozen in brine in polyethylene bags. A more recently developed

freezing technique is the individually quick freezing (IQF) process.

The individually frozen meats can then be stored in containers of any

desired size and removed in any quantity as needed without thawing.

Several methods of IQF have been used. The meats may be spread out in

trays and frozen in a blast freezer, or in evacuated polyethylene bags

injected with nitrogen. The latter process improves preservation and

retards dehydration.

c. Raw, peeled and frozen. This is probably the most universal

266

process in the Maine industry (Table D-2-4). Aut omatic machine peeling

is customary. The machinery has been developed largely by a single

company (the Laitram. Corporation of New Orleans) and is rented to the

processor on an hourly basis. A royalty fee is also charged for each

thousand pounds of shrimp processed. The freshly caught shrimp, culled

and washed, are soaked in fresh water for 12 to 18 hours to loosen the

connective tissue between the meat and the shell. They are then fed

into the peeling machine along with a copious flow of water, which

helps move them along the processing line. The machine can process

500-900 pounds an hour, consuming 5000 gallons of water or more while

doing so (Demarest 1971). Bits of shell and other inedible parts are

removed after peeling in the last stage of the machine, the cleaner and

separator. The meats are inspected, dipped in brine and frozen in

plastic bags, or dipped in boiling brine and then individually quick

frozen.

f. Peeled and canned. For canning, the peeling process is as just

described, but after final inspection the meats are vacuum packed and

heat sterilized in cans. Only a few firms in Maine have undertaken canning

as a means of processing shrimp.

7. Legal constraints on processing. There are presently no state

laws that restrain the processing sector, except for a single statute

that requires labeling packaged shrimp as to the state or country of

origin. The legal authority to promulgate regulations and establish

standards for processing is possessed by both the Department of Mari ne

267

Resources and the Department of Agriculture. Federal health and

sanitation standards must be met since the industry involves interstate

and overseas shipments of the product.

8. Problems relating to processing. One of the major problems for

processors is the continuity of the supply. Once money is invested in

facilities and equipment, it is necessary that a dependable flow of

shrimp pass through. During periods of scarcity the supply may be

irregular. It has been estimated (Northern Shrimp Scientific Committee

1979) that 700 thousand pounds of shrimp a year must be processed by

a machine to offset its cost to the processor.

V. MARKETING

1. Levels of distribution. The markets for northern shrimp fall

into three categories-local, interstate and foreign. The product and

the pathways of distribution vary accordingly. Basically, the steps of

marketing are the fisherman, the processor, the wholesaler (who may also

be the processor), the retailer (who may also be any of the other three),

and the consumer. The fisherman, who sometimes sells directly tothe

consumer when the demand is: low, seldom goes to this trouble when the

demand and proce are high, and processors or wholesalers will take all

he can provide. Processors may also stop selling directly to the

consumer under these circumstances. Wholesalers, who are not necessarily

close to the supply, deal largely with the canned or frozen product.

Retailers, consisting of chain food stores, local grocery stores and fish

markets, roadside dealers often selling from the backs of pickup trucks

268

and restaurants, may buy the product from fishermen, processor or whole-

saler.

2. Shipping. Shrimp are customarily shipped in regrigerated

trucks; those destined for European markets are packed in 22 pound

containers and transferred to commercial airliners in New York or

Boston,

3. Legal constraints. State laws affecting the marketing of

shrimp are minimal. According to Henry and Halperin (1970) "...no

provision of Maine law is a significant impediment to the exploitation

and marketing of marine products as food," and shrimp have fewer provisions

under the law than many other sea foods. Licenses are required for

wholesale.marketing of fish generally. The pertinent Maine laws apply to

all foods and are intended to protect the consumer from such things as

fraudulent labeling or unsanitary or unwholesome products. These laws,

administered by the Department of Agriculture also make special

provisions for perishable foods including sea foodSr providing for the

inspection of food products and, if necessary, the condemnation of

spoiled items. Inspections of this kind are limited in scope and

frequency by funds and personnel available. The Department of Agriculture

also publishes guidelines, without force of law, called Good Management

Practices.

The Maine food laws also deal specifically with frozen foods and the

Department of Agriculture sets standards for temperature control in

storage and transportation. Processors of food products may request

269

regular inspections of their products: a service for which a fee is

charged, but since the product may then be labelled " inspected," the

service may have some advertising benefits (Henry and Halperin 1970).

Federal laws, after which Maine food laws are patterned apply to

interstate shipments. They are administered by the Food and Drug

Administration.

4. Economic factors. Marketing of northern (Maine) shrimp is

competitive on three levels-with fish, meat and poultry products

generally; with southern shrimp of other species; and with Alaskan,

Canadian and Scandinavian shrimp of the same or similar species.

Recently, also, frozen small shrimp meats resembling those of Maine

shrimp have been imported from Asia.

Regarding the competitive relation of shrimp to other fish and

meat products, this appears to be no problem as long as the economy of

the country as a whole is good (National Marine Fisheries Service 1978).

Shrimp is a so-called "luxury" food item, is consumed to a large extent

by higher income groups, and consumption has been increasing contrinuously

over the past two decades (Fig. D-2-6).

Competition with southern shrimp is not a problem as a general

rule. The demand for all shrimp is high, as is,reflected by increasing

consumption and increasing price, and the prices paid.for Maine shrimp

have kept pace (Fig. D-2-6). One exception to this can be noted during

the period 1960 to 1965, when the price of Maine shrimp dropped as the

supplies began to increase, even though prices generally held firm. The

270

apparent reason for this is that for several years prior to 1960, Maine

shrimp had been scarce or off the market entirely, and their return was

slow to be accepted by the consumer. Their place in the domestic

market was eventually recovered, although a simultaneously developing

European market helped boost the demand in 1969 and 1970.

If the demand for shrimp generally were to decrease, it is possible

that competition with southern shrimp would be felt more. These larger

shrimp are more familiar nationwide and are probably preferred. In 1969,

a year when Maine shrimp were being landed in peak quantities, Maine

landings were about 8% of the total shrimp landings in the United States,

yet they represented only 3% of the total United States consumption.

Fortunately, Scandinavian and other European.countries, plagued by

shortages in their own supply, provided a needed market and about one-

third of the Maine catch, or roughly 8 million pounds per year were

exported (U.S. Bur. Comm. Fish. 1969).

These foreign markets are not always available, however. Their own

supplies have been increasing in recent years, and both Canada and

Greenland are able to supplement their needs if necessary. Alaska

shrimp, being the same or closely related species to the northern shrimp

harvested in Maine, are a potential source of competition. The Alaska

landings which were 43 million pounds in 1969, not quite twice the Maine

landings, reached 116 million pounds by 1977: 300 times the Maine

landings for that year and over 4 times the biggest Maine catch in any

year. Because of marketing problems, and the quantities landed, the

271

price of Alaska shrimp is low: less than 5 cents a pound in 1973,

now not over 15 cents. In the past competition from Alaska shrimp

may not have been a serious problem. Certain properties of their

tissues made machine peeling difficult (U.S. Bur. Comm. Fish. 1969)

and most were canned, a market toward which the Maine industry was not

strongly oriented.

ECONOMIC IMPORTANCE

From the time the shrimp are landed until they are purchased by

the consumer either as a product for home consumption or as a meal in

a restaurant, many segments of the economy share in the profit. The

landed values of the shrimp have already been mentioned (Table D-2-1).

The retail values can be estimated by multiplying these values by an

appropriate factor (the shellfish multiplier), which for shrimp is

approximately 2.8 to 3.0 (Hamlin and Ordway 1974). Thus for the year

of highest value (1971) the retail value was probably between 6 and 7

million dollars for the two-thirds of the catch marketed domestically.

Of the landed value (that paid the fisherman) 45 to 50%, depending

on the category of vessel, goes to pay the crew, captain or owner (if

owner operated); most of the rest goes for expenses which include

maintenance of vessel and gear, purchase of supplies, equipment,

depreciation, insurance, etc. (Table D-2-5). About 3% accrues to the

state and federal government as taxes (not including income taxes).

About 44-45% of the earnings of the boat when shrimp fishing go to

pay expenses. In a year of relatively great value of landings (e.g., 3.6

272

million dollars in 1971) 45% of this or 1.62 million dollars would thus

add to the earnings of shipyar ds, repair shops, skilled tradesmen, and

miscellaneous laborers. Other portions of it would go to food dealers,

fuel dealers, hardware stores, ship chandlers and numerous other

enterprises.

No reliable information is available to indicate precisely the

number of people employed as fishermen in the shrimp fishery. At the

peak period (1969-1975) between 270 and 300 Maine boats were engaged in

the fishery and the average crew size was a little over three men

(Dunham and Mueller 1976). The number of fishermen earning all or' part

of their income from shrimp fishing would appear to have been from 800

to 1000.

The number of all persons employed in one way or another in the

shrimp industry was estimated (Northern Shrimp Scientific Committee 1979)

to be about 800 in 1976, with nine processors in operation. This

figure includes fishermen, handlers, plant personnel, truckers, etc. In

1970, with 20 processors in business, it can be assumed the total number

employed was about double the 1976 figure.

EVALUATION OF REGULATORY FRAMEWORK

The shrimp fishery in Maine is relatively new and its regulation

in all phases is minimal. This is partly due to a reluctance on the

part of lawm akers and regulatory agencies to inhibit a developing

industry and partly because for a long time nobody knew enough about

the shrimp or the fishery to formulate a sound management policy. Only

273

in recent years have circumstances combined to make regulation both

necessary and feasible. Even now, although most people concerned agree

that some kind of management is necessary, there is no general agreement

on how or how much. -

1. Management of the resource. The management of the shrimp

fishery has been almost entirely relegated to a joint federal-state

authority under the auspices of the Atlantic States Marine Fisheries

Commission. This authority, the Northeast Marine Fisheries Management

Board comprises the directors of the marine fishery conservation

departments of the seaboard states from Virginia to Maine. The

representatives from Maine, New Hampshire and Massachusetts and the

Regional Director of the National Marine Fisheries Service make up the

Northern Shrimp Sub-board. Members of this sub-board serve also on the

Northern Shrimp Section of the ASMFC along with representatives from the

legislatures and the shrimp industries of the three states. The Northern

Shrimp Sub-board has associated with it a Northern Shrimp Scientific

Committee, composed of fishery scientists from the three states and

the National Marine Fisheries Service. The joint, three-state

management agency seems reasonable since the shrimp of the Gulf of Maine

are a common resource for the three states involved.

The need for some regulation was first seriously recognized when

a declining trend in shrimp abundance was becoming apparent in 1972. Of

three management strategies considered-maximum counts per pound in

catch, closed seasons, or minimum mesh sizes for gear-only the last

274

appeared feasible at that time and standard minimum mesh sizes were

recommended. Until a gear evaluation study could be made, an interim

minimum mesh size of 1.5 inches was adopted by each of the three

participating states, and ultimately a stan dard minimum mesh size of

1.75 inches was adopted by the board in June 1975. Although this mesh

size was supposed to have been scientifically calculated to permit the

retention of mature females and the escapement of most of the transitionals

and males, it appears to have been no larger than the standard mesh size

in general use already (Bruce 1971).

Besides the mesh size regulation, which is still in effect, several

seasonal closures and quotas have been instituted at one time or another

for limited periods of time, none of which seemed either to have had a

noticeable effect on the shrimp stocks or to have been accepted

enthusiastically by all parties concerned. Although heavy fishing on

spawning populations is generally disfavored when conservation of stocks

is called for, and is restricted to some degree in many northern shrimp

fisheries, it is practiced freely in Maine. The egg bearing females are

considered to be the most desirable for harvesting, and protection during

that period is not the kind of management that Maine industry is seeking.

They would prefer.seasonal restrictions on the offshore summer fishery

which takes a high percentage of the young males. On the other hand,

the Massachusetts industry, while not adverse to closures in the winter

time, is not enthusiastic about summer closures in the offshore fishery,

which they pursue almost exclusively.

275

Closed seasons have been in effect on three occasions: July 5 to

September 27, 1975, April 15, 1976 - Jan. 1, 1977 and May 15, 1977 through

1978. The latter closure was terminated ea rly in 1979, after considerable

debate. The position of the various segments of the industry in the

matter of management is based largely on economic arguments, which are

understandable, if not without considerable self-interest. Unfortunately,

the position of those responsible for management, although presumably

objective, is divided by disagreement and lack,of information about the

basic ecology of the shrimp. The divergence of opinion hinges on whether

the abundance of shrimp is so overwhelmingly determined by the environment

that attempts to maintain it or change it by control of fishing effort

are futile, or whether it is so strongly affected by overfishing that any

reduction of the latter will restore depleted stocks more quickly, or

will prevent depletion altogether. The above arguments represent the

extreme polarization of views; there are many opinions as well that lie

somewhere in the middle.

Although neither the Northern Shrimp Sub-board nor the Atlantic

States Marine Fisheries Commission have been unanimous in their views

toward management or have so far produced an effective management scheme,

a draft for a comprehensive management plan has been recently prepared

by the Scientific Committee for consideration by the Northern Shrimp

Sub-board.

2. Research. Whatever the fate of the management plan, the

Scientific committee has, to its credit, accumulated a respectable

276

volume of scientific data which should render management decisions and

appropriate regulations much easier to make. Federal and state laws

which authorize this research should be mentioned, therefore, as part

of the total legal framework applicable to the shrimp fishery. The

Commercial Fishery Research and Development Act of 1964, P.L. 88-309 is

one of the more important of these. Under this law half the cost of a

fish ery research project undertaken by a state is funded by the federal

government and half by the state. Maine currently has two P.L. 88-309

research projects on shrimp.

3. Problems. The overriding problem with the present legal

framework is that it was not adequate to cope with the rapid expansion

of the fishery. Inadequate information and'basic philosphical

disagreements about management, self-interest and ineffectual enforcement

of even existing regulations have all been contributory to the failure

of managing the fishery before it declined, assuming that it could

have been managed even if stricter measures had been taken. The first

two of the difficulties mentioned above have been discussed; the last,

the problem of enforcement, stems mainly from the by-catches of shrimp

with other species. This can occur purposefully, even assisted by the

use of smaller than legal sized meshes. The illegal harvesting of

shrimp in this manner is difficult to prevent.

CONFLICTS IN RESOURCE UTILIZATION

In the earliest period of the shrimp fishery, the resource was

277

essentially fortuitous, in a sense almost a recreational fishery,

pursued in the off season of other fisheries. There was little

conflict in the utilization of the resource because it was not that

important in the fishing industry generally. It is still an off-

season resource for many fishermen, but for others it has become a

year round and, until recently, a primary pursuit. This and other

factors lead to a number of conflicts in its utilization.

In Maine, the fishery is essentially a winter fishery on egg-

bearing females. In Massachusetts the fishery is year round and in the

summer takes all age groups including males. This leads to a conflict

between the Maine and Massachusetts fishing interests, not only on

biological issues relevant to conservation, but also in respect to the

kind of management restraints employed.

of lesser concern is a conflict resulting from the kind of gear

employed. The trap fishery, which developed rather precipitously in

1970, found itself in conflict with the established trawl fishery wherever

both attempted to harvest the same areas. Because traps can fish in areas

impractical for trawling, however, reasonable arrangements should be

possible for alloting certain areas for each fishery. Analagous conflicts

between shrimp trawler and lobster fishermen may occur, but since many

shrimp trawlers are also lobstermen, the problem is probably incidental.

The possibility of conflicts among various kinds of fishermen and

with other marine interests for the use of dock facilities and mooring

space has been suggested. The shrimp industry declined before such

278

problems actually arose, but since shrimp fishermen and fishing boats

were, for the most part, the same people and the same boats as helped

make up the already existing fishing fleet, no additional pressure was

likely to be put on facilities. If a great expansion should someday

occur in the shrimp fishery, especially with corresponding expansion

of other marine activities, such conflicts might be possible.

The greatest conflict in the shrimp picture at the present time is

between a large body of the industry supported by some elements of the

scientific sector on one hand and management interests supported by

other scientists on the other, who seem to have taken opposing views

as to the nature of the periodic declines in shrimp abundance and the

philosophy of managing the resource.

SUMMARY

Unfortunately, at the present time the shrimp fishery in Maine has

to be discussed in retrospect. Whether the brief prosperity of the late

sixties and early seventies will ever return no one can say. It is

widely assumed, that the nature of PandaZus boreaZis in the Gulf of

Maine is such that its abundance is more or less cyclical and that any

fishery based upon it will be subject to rather severe extremes of

dearth and plenty. Many hope that rational management might smooth out

these extremes so that a fishery could be carried on at at least modest

levels even on the down swing of the cycle, or at least so that the high

.fishing effort that develops when shrimp are plentiful and the market

279

good does not continue irresponsibly when shrimp abundance clearly

starts to decline. Until the ecology of the shrimp is more clearly

understood, especially the causes for extreme fluctuations in abundance,

any method of management and its outlook for success will probably

remain debatable.

290

Sof

ROCKLAND

HBR
BOOTHBAY

0 jf
PORTLAN

@kSS.-. CAPE ANN

Figure D-2--I. Gulf of Maine, showing areas of relatively dense (vertical

shading), medium (horizontal shading), and sparse (stippled)

populations of PandaZus borealis, from surveys made in spring

and fall of 1963-65. (Adapted from Haynes and Wigley, 1969).

281

YEARWINTER

SPRING

SUMMER

C-
WINTER c
SPRING M
z

SUMMER M
cn

WINTER MALES

SPRING
3 SUMMER

IFALL
WINTER TRANSITIONAL
SPRING
4 SUMMER

FALL OVIGEROUS FEMALES I
WINTER SPENT FEMALES I
SPRING

SUMMER
FALL OVIGEROUS FEMALES :11
WINTER
6 SPRING SPENT FEMALES Z:
SUMMER

FALL

INSHORE OFFSHORE

Figure D@2-2. The life history of PandaZus boreaZis showing approximate

times and durations of life history stages and offshore-
1
IGE1

T
CSVPEN

0 C
7S VPE I

inshore migrations.

282

4.0

.70-

.65- 3.5

60-

55- 3.0
Z
< 0
50

0
45 2.5
.40- LLJ
Z

0 35-
CL 2.0
1-1 30-
Ld

.25 0
CL .20 Ot 1. 5

-15 k 1.0

.10

.05 A16

1940 1945 1950 1955 1960 1965 1970 1975 1980
YEARS

Figure D-2-3. Maine landings of PandaZus boreaZis since 1938 and price per

pound to the fisherman. The landings in metric tons are

shown on a logarithmic scale to exaggerate those of the

1940-1950 period and to emphasize the cyclic nature-of shrimp

abundance.

283

5OF ...... ....

ROCKLAN6

BOOTHBAY HBR.

PORTLAN
(6)

ev:'

CAPE ANN

Figure D-2-4. Gulf of Maine, showing the distribution of egg bearing females

in the winter (heavy shading: during periods of abundance;

light shading: since 1976) and the location of'the winter

fishery, as it was at its zenith and in more recent times.

Locations of shrimp processing plants in 1969 are shown as

black dots.

284

10- A
8
0
6

0
4

60 -
5 0
40
30 -
0
Y 20 -
lo-

4.0 -

3.0-
z
0 2.0-
2 1.0-

0.4-

cn Q3 -
z
0 0.2-
0.1-

1964 1966 1968 1970 1972 1974 1976 1978

YEARS

Figure D-2-5. Abundance indices, based on catch per unit effort of various
classes of fishing vessels.

A. Mean kilograms per tow from National Marine Fisheries
Service research cruises: dotted line, autumn; solid line,
spring.
B. Mean kilograms per 30-minute tow, Maine summer research
cruises.
C. Metric tons per day; total for all commercial vessels in
34-50 gross tonnage class.
D. Metric tons per hour; total for three selected vessels in
winter fishery (from Rinaldo, 1976).

Data taken from Northern Shrimp Scientific Committee, 1979.

3.00- PRICE,ALL SHRIMP,AVERAGE - 600
CONSUMPTION,ALL SHRIMP
-2.50- PRICE , MAINE SHRIMP (x5) - 500

U)
0
0 2.00-
400
0
a_
0
z LL
D 1.50- 300 0
0
CL U) OD
1@1 "-- z Ln
LLJ 0
0 1.00 /*--a- __j
200

.50 1W

0 0
1960 1962 1964 1966 1968 1970 1972 1974 1976 1978
YEAR

Figure D-2-6. Trends in nationwide consumption of shrimp (all species), average price per pound
to fisherman (all shrimp) and price per pound to fisherman for Maine shrimp
(multiplied by a factor of 5 so that all three trends would fit on a single scale).

an as few so me

286

Figure D-2-7. Sea water temperature trends from 1940 to 1978. Data points represented by circles
are means for actually measured bottom temperatures in the Gulf of Maine in November
(National Marine Fisheries Service, groundfish survey cruise). Solid lime represents
assumed mean bottom temperatures for November calculated from the relationship between
15- observed November bottom temperatures and observed August surface temperatures In
Boothbay Harbor. Dotted line represents annual mean surface temperatures measured
at Boothbay Harbor.

.............. MEAN ANNUAL SURFACE TEMPERATURE

_____________ ESTIMATED NOVEMBER BOTTOM TEMPERATURE

_ _ _ _ _ OBSERVED NOVEMBER BOTTOM TEMPERATURE
(DAVIS 1978)

Table D-2-2. Catch, stock size, recruitdent estimates, and related parameters used in assessment of the
Gulf of Maine northern shrimp stock.1 Estimates of instantaneous fiehing mortality (F)
were calculated from analysis of Maine survey catch at age data assuming M 0.2S (from
Northern Shrimp Scientific Committee 1979).

Instantaneous Exploitation Survival
Year fishing mortality rate rate Catch Stock Size4 RecruitmellO
(F)2 (u) (S) (Nrr3x 10-3) (MT x 10-3) (MT x 10- 3)

1968 0.71 0.456 0.383 6.6 14 --
1969 0.75 0.474 0.368 12.8 27 22
1970 0.69 0.447 0.391 10.6 23 13
1971 1.95 0.788 0.111 11.1 14 5
1972 1.72 0.752 0.139 11.1 is 13 f1j
OD
1973 0.87 O.S24 0.326 9.4 18 16
1974 1.80 0.765 0.129 7.9 10 4
197S 1.416 0.688 0.190 5.3 8 7
1976 0.98 0.564 0.292 1.0 2 1
1977 1.98 0.792 0.108 0.4 1 1
1978 0.54 0.373 0.454 - - -

1Data taken from Clark and Anthony (in press)

21Veighted by catch in numbers at age

3Metric tons

4Calculated by dividing catch by exploitation rate

SCalculated by subtracted survivors (year i) from stock size (year i+l), e.g., the 1979 estimate is
calculated as 27-14 (0.383)
6Estimate of F could not be calculated directly for 1975 due to introduction of a now survey vessel.
Accordingly, the 1973-1977 average was used.

$0 Un M low "as too

288

Table D-2-3. *Vessels in. the Gulf of Maine northern shrimp fishery by year
and state.1

'Year -Maine- -MA- -NH- Total

1965, (29] -4- 33

74 -11- 1 86

1967 (107] -22- 2 131

1968 [223] 32 2 251

1969 [287] -42- 3 332

1970 [2841 60 3 347

1971 [285] 55 3 343

1972 [2Sl] S4 4 309

1973 [292] S3 3 348

1974 331 46 377

1975 [270] (47) 317

1976 [127] (18) 145

1977 (23) 23
I 'Data are derived from various sources as indicated.

State of Maine records

State of Massachusetts records

Wigley, 1973

Otherwise NMFS data files

From Northern Shrimp Scientific Committee 1979

289

Table D-2-4. *List of firms processing shrimp in Maine durina 1969,
including location and types of shrimp products.

Bath Canning Prospect Harbor Raw meats, raw headless
Belfast Canning Co. Prospect Harbor Raw meats
Windjammer Sea Farming Eastport Peeled, raw (canned
Corp. natural)
A.M. Look Canning Co. East Machias Dip (canned and natural)
Three Rivers Fish Co. Jonesport Raw meats
Brown Fish Company Portland Raw meats
Central Wharf Fisheries, Portland Raw meats
Inc.
Eastern Fish Company Portland Raw meats
Mid-Central Fish Co. Portland Raw meats, raw headless
Stinson Canning Co. Prospect Harbor Raw meats
F.J. O'Hara & Sons, Rockland Raw meats, raw headless
Inc.
Royal River Packing Co. Yarmouth Raw meats, raw headless
Scandia Seafood Co., Bailey Island Cooked whole
Inc.
Malpeque Shrimp, Ltd. Boothbay Harbor Cooked whole
Maine Biological Brunswick Raw meats
Supply & Develop-
ment Corp.
Maine Lobster Co. Portland Raw meats
Maine Crabmeat Co. Portland Raw meats
Gulf of Maine, Inc. Portland Raw meats, breaded
Paul Bayley Seafoods Scarborough Raw meats, raw headless
Company
Port-Lobster Company Kennebunkport Raw meats
Rockland Shrimp Corp. Rockland Cooked whole
Mill Cove Lobster Co., Southport Cooked whole
. (No. 2)
Atwood Brothers, Inc. St. George Cooked headless, raw
meats
Mill Cove Lobster Co., Trevett Raw meats
(No. 1)

*From Whitaker 1971

290

Table D-2-5. Breakdown of average income and costs for vessels engaged in
the New England shrimp fishery (based on Dunham and Mueller,
1976).

Incorporated Owner Operated
Vessels Vessels

Gross Earnings $97,847 $53,975

Captain and Crew 47,072 (48 %) 24,302 (45 %)

Maintenance 10,466 (10.7%) 6,124 (11.3%)

Equipment 4,868 S.0%) 3,162 S.800-)

Supplies 21,012 (21.0%) 9,484 (18.0%)

Miscellaneous 7,828 8.0%) 4,920 9.1%)

Taxes 4,107 4.2%) 1,431 2.6%)

291

References

Allen, J.A. 1959.
On the biology of PandaZus boreaZis KrOyer with reference to a
population off the Northumberland coast. J. Mar. Biol. Ass. U.K.
38:189-220.

Apollonio, S. and E.E. Dunton. 1969.
The northern shrimp, PandaZus boreaZis, in the Gulf of Maine.
Project 3-12-R Completion Report, Dept. of Sea and Shore
Fisheries, Augusta, Maine. 81 p., 32 figs.

Bigelow, H.B. and W.C. Schroeder. 1939.
Notes on the fauna above mud bottoms in deep water in the Gulf of
Maine. Biol. Bull. 76:305-324.

Birdseye, C. 1928.
Shrimp fishing out of Gloucester, the story of a new industry.
Fishing Gazette 4S:12-13.

Bruce, R.A. 1971.
The New England shrimp fishery. In Proc. Conf. on Canadian Shrimp
Fishery 1970. Canadian Fisheries Reports 17:257-278.

Bureau of Commercial Fisheries. 1964.
Shellfish Situation and Outlook. U.S. Fish. Wildl. Serv. Current
Economic Analysis S-12, March 1969:1-43.

Captiva, F.J. 1971.
Boats used in some major shrimp fisheries. Session 4, Discussion,
Proc. Conf. on Canadian Shrimp Fishery 1970.- Canadian Fisheries
Report 17:325-328.

Demarest, L.E. 1971.
Shore processing and handling in the United States. Proc. Conf.
on Canadian Shrimp Fishery 1970. Canadian Fisheries Report 17:175-
177.

Dow, R.L. 1973.
Fluctuations in marine species abundance during climatic cycles.
Mar. Technol. Soc. J. 7:38-42.

Dow, R.L. 1979.
Dow cites sea temperature as key to fluctuations in shrimp resource.
National Fisherman 60(3):36-37.

292

Dunham, W.C. and J.J. Mueller. 1976.
The economic impact of a reduction in shrimp landings under
regulated and unregulated programs. Ms., University of Maine,
Dept. Res. and Agr. Econ. Orono, Me. 49 p.

Hamlin, C. and J.R. Ordway. 1974.
The Commercial Fisheries of Maine. Ocean Research Corporation,
Kennebunk, Maine. 106 p.

Haynes, E.B. and R.L. Wigley. 1969.
Biology of the northern shrimp, PandaZus bareaZis, in the Gulf of
Maine. Trans. Am. Fish. Soc. 98:60-76.

Henry, H.P. and D.J. Halperin. 1970.
Maine Law Affecting Marine Resources, IV. Resources from the Sea
and Federal Limitations on State Control, University of Maine
School of Law, Portland, Maine:629-903.

Horsted, S.A. and E. Smidt. 1956.
The deep sea prawn (PandaZus boreaZis Kr.) in Greenland waters.
Medd. Komm. Havundersog., N.S., 1(11):118 p.

14jort, J. and J.T. Ruud. 1938.
Deep sea prawn fisheries and their problems. Hvalr9d. Skr. 17:144 p.

Maurer, R. and R.E. Bowman. 1975.
Food habits of marine fishes of the Northwest Atlantic. Data Rept.,
Nat. Mar. Fish. Serv., Woods Hole; Lab. Ref. Doc. No. 75-3, 90 p.

National Marine Fisheries Service. -1978.
Shellfish Market Review. U.S. Dept. Commerce, Current Economic
Analysis, S-41 November 1978:1-51.

Northern Shrimp Scientific Committee. 1979.
Draft fishery management plan and environmental impact statement
for northern shrimp (PandaZus boreaZis). Northern Shrimp Sub-Board,
Northeast Marine Fisheries Management Board, Mimeo Rept. 141 p.

Rathbun, R. 1884.
Part V. Crustaceans, worms, radiates and sponges. In Goode, G.B.
The fisheries and fishery industries of the United Si-tates, Sec. 1,
Washington, D.C.:759-850.

Rinaldo, R.G. and P. Yevich. 1974.
Black spot gill syndrome of the northern shrimp, PandaZus boreaZis.
J. Inv. Path. 24:224-233.

293

Savoie, J.B.R. 1971.
Shrimp packaging and shipping methods. Proc. Conf. on Canadian
Shrimp Fishery 1970. Canadian Fisheries Report 17:213-226.

Scattergood, L.W. 1952.
The northern shrimp fishery of Maine. U.S. Fish. Wildl. Serv.,
Comm. Fish. Rev. 14:1-16.

Stickney, A.P. 1978.
A previously unreported perididinian parasite in the eggs of the
northern shrimp, PandaZus borealis. J. Inv. Path. 32:212-215.

Squires, H.J. 1968.
Relation of temperature to growth and self-propagation of PandaZus
borealis in Newfoundland. FAO Fisheries Report 57(2):243-250.

Stickney, A.P. and H.C. Perkins. 1977.
Environmental physiology of commercial shrimp. Project 3-202-R
Completion Report, Dept. of Marine Resources, Augusta, Maine. 78 p.

Stickney, A.P. and H.C. Perkins. 1979.
Environmental physiology of northern shrimp, PandaZus borealis.
Project 3-277-R Completion Report, Dept. of Marine Resources,
Augusta, Maine. 66 p.

Uzmann, J.R. and E.B. Haynes. 1968.
A mycosis of the gills of the pandalid shrimp DicheZopandalus
Zeptocerus (Smith). J. Inv. Path. 12:275-277.

Whitaker, D.R. 1971.
The New England shrimp industry. In Proc. Conf. Canadian Shrimp
Fishery, Can. Fish. Rep. 17:433-440.

294

ELEMENT D-3: A CHARACTERIZATION

THE MAINE LOBSTER FISHERY

Walter R. Welch

295

INTRODUCTION

The American lobster (Homarus americanus) was, in 1978 as it has

been for some time, the most valuable marine resource in Maine. With

1978 landings of 19,130,459 pounds, it was valued at $33,878,376 at

first sale.

The lobster resource is intensively exploited, but miraculously,

the year-to-year fluctuations in landings over the past 3 decades have

occurred at fairly high levels.

To ensure continued high levels of production of this valuable

resource and perhaps even bring about modest increases, serious

consideration of workable management strategies seems called for.

296

TABLES
Page
310
D-3-1. Catch of lobsters in Maine, 1880-1978 ..................

D-3-2. Annual catch of lobsters in Maine by counties, 1969-1978. 312

D-3-3. Some total estimates for lobster fishing in Maine ........ 313

D-3-4. Maine lobster population parameters ...................... 314

D-3-5. Catch of Maine lobsters by months, 1975-1978 ............. 316

297

FIGURES

Page

D-3-1. Total lobster landings, total value, and average price

per pound. Maine, 1880-1978 ............................. 317

D-3-2. Total lobster landings, total number of fishermen, and

total number of traps. Maine, 1880-1978 ................. 318

D-3-3. Annual catch of lobsters in Maine by counties, 1969-1978. 319

D-3-4. State of Maine map with county designations .............. 320

D-3-5. Traps per boat in Maine lobster fishery .................. 321

D-3-6. Lobster catch-effort 1897-1976 ........................... 322

D-3-7. Catch per unit of effort in lobster fishery .............. 323

D-3-8. Calculated lobster growth curves (von Bertalanffy) ....... 324

D-3-9. Catch of Maine lobsters by months, 1975-1978 ............. 325

298

Distribution of the Resource

The American lobster (Homarus americanus) is found from Labrador

and Newfoundland to the Carolinas, from shallow coastal waters to 370

meters (200 fathoms), and in a wide variety of habitats. The greatest

commercial concentrations occur along the Maritime Provinces of Canada.

In Maine waters the lobster is distributed all along the coast,

around the islands, and into bays, harbors, and estuaries as far as

relatively high salinities (in excess of 20%, Dow, et. al., 1975) extend.

Ledges, reefs and rocky bottoms seem to be preferred for habitat, but

the species can be found on practically all types of bottom. The specific

areas inhabited by the resource are too numerous and widespread to be

described in narrative. They may be seen as designated on the Maine

Coastal Inventory maps of the Maine State Planning office (An on., 1976).

299

AVAILA13ILITY OF THE RESOURCE

Lobster fishing seems to have begun in the.Boston area and lobsters

were marketed there at least as early as 1740. By 1880 the fishery had

extended northward into the Canadian provinces and south to Delaware.

In that year, United States landings totaled 20.3 million pounds, of

which 19.9 million pounds came from, New England, and 14.2 million

pounds from Maine alone (Anon., 1978). Over the years of record,

Maine's landings have fluctuated widely from 25.0 million pounds in

1887, to 5.1 million pounds in 1936, to 24.4 million pounds in 1957

(Table D-3-1, Figures D-3-1 and D-3-2). Over the past 3 decades, the

catches have been at a fairly high level.

The lobster.producing areasof the Maine coast are shown on the

Maine Coastal Inventory charts, Fish and Wildlife #1 (Anon., 1976).

From these, it appears that the lobster is fished all along the Maine

coast and its islands, coves, harbors, and estuaries. However, from

Table D-3-2 and Figure D-3-3 it may be seen that Knox and Hancock

counties are consistently major producing areas, while York and Sagadahoc

counties are consistently minor producing areas, There are probably

many reasons for the differences in the lobster landings among the

several countiesf but it seems certain that the relatively small amounts

of shoreline and adjoining ocean areas in York and Sagadahoc counties

(Figure D-3-4) must play a large part in their limited landings.

300

Variations in Availability

Lobster larvae are planktonic and remain so for 2 to 5 weeks after

hatching, depending upon temperature. During this period the larvae

are distributed by water currents and may settle to the bottom many

miles from where they were hatched. Because of this, the lobster

population and therefore the fishery in one area may be dependent for

larval recruitment upon the spawning stock of lobsters in another area.

Because the larvae of this species have not been studied extensively,

there is little known about their distribution and abundance along the

northeast coast of America. The existence of a counterclockwise current

flow in the Gulf of Mainef however, gives reason to speculate that stocks

of adult lobsters in the north to northeast parts of the Gulf of Maine

may be important sources of larval recruitment to the coast of Maine.

Similarly, larvae hatched in inshore areas may contribute to recruitment

in offshore areas.

The movement of lobsters over the bottom also contributes to the

intermingling of stocks from different areas. Krouse (1978) reviewed

all lobster tagging studies conducted along the coast of northeastern

America and found certain patterns of movement to be evident. The one

most pertinent to the Maine lobster resource was the south or south-

westerly movement of predominantly large, mature lobsters. Extreme

distances of movement cited were: 113 nautical miles in 7 months (Dow,

1974); 185 nautical miles in 199 days; and 63 nautical miles in 369 days

(Krouse, 1977a). However, several studies of lobster movement

301

showed it to be very minimal forthe most part, Krouse 119781

interpreted the overall results to indicate that certain sizes of

lobsters (primarily smaller, sexually immature) inhabiting certain

area s are generally nonmigratory.

Because of the above evidence of intermingling and movements of

larvae and adults, and until more is known about migrations and larval

recruitment relationships, the American lobsters in the Northwest

Atlantic should be considered as a single stock (Anon., 1978).

At present there.is not sufficient information at hand to estimate

the size of the spawning stock necessary to sustain a given level of

recruitment. There is need for studies to produce basic information

on annual egg or larvae production.and subsequent recruitment to the

fishery.

Table D-3-4 summarizes the status.of development of lobster

population parameters that have evolved from various lobster research

projects. These data form an important basis for assessment of the

condition of Maine lobster stocks and for recommending management

strategies.

The availability of the resource to the fishery must be primarily

dependent on the size (in numbers) of the resource. This is particularly

true in the case of the Maine lobster resource, in which 86% of the

legal-sized lobsters are removed by the fishery each year, and in which

the commercial catch is largely dependent (77%) on lobsters molting from

sublegal to legal size (Thomas, personal communication).

302

The Lobster Project of DMR, in progress since 1966, was set up to

conduct a statistical (probability) sampling of the commercial lobster

catch in Maine to obtain detailed data on the catch, on the effort

expended, and on certain biological aspects of the lobster resource.

In addition to the development of some of the population parameters

mentioned below, summary data on fishery statistics and catch-effort

aspects were compiled as shown in Table D-3-3 and Figures D-3-5, D-3-6,

and D-3-7.

Some information has been developed which bears upon recruitment

problems. For instance, Krouse (1973) found that only 6% of females

in Maine waters mature (as judged by extrusion of eggs) under 90 mm

carapace length, whicle nearly all are mature by the time they are

105 mm, and accomplish egg extrusion between Mau and July. It is

evident that in Maine, with a minimum size limit of 81 mm (3-3'/16 inches),

many females would be caught before they even become sexually mature.

In fact Thomas (1973) indicated in length frequency plots of samples

from the 4 years 1967-1970 that 60 to 90% of the females in the catch

were below the size at maturity could be expected.

Mortality must be considered as having a very strong influence on

the abundance of the lobster resource. Thomas (1973) assigned a range

of instantaneous total mortalities of 1.14 (67.9%) to 2.92 (94.6%),

depending upon the methodology used in deriving the values. Similarly,

he gave a range of 0.02 (2.0%) to 0.35 (29.3%) for instantaneous natural

mortality but favored a level of 10% or below.

303

In the wild, lobsters are subject to the usual types of predation.

The larvae are preyed upon by ctenophores and other types of zooplankton.

The juveniles on bottom are taken by a wide variety of bottom-feeding

fish such as cunner, pollock, and lumpfish. Fishes such as cod and wolf-

fish prey upon a wide range of sizes of lobsters (Anon., 1978).

Cannibalism can be a problem during molting in dense populations or

when sufficient cover is not available.

Two potentially serious diseases are found in lobsters taken in the

wild. The blood bacterium, Aerococcus viridens, causes gaffkaemia or the

so-called."red-tail." It is the more virulent of the two and can lead to

death by impairing the oxygen-carrying ability of the blood. The other,

called "shell disease" is caused by the destruction of the:chitinous

outer layer of shell by chitinivorous bacteria. It causes erosion of

the shell surface and lowers the quality of the lobster, but seldom

causes death unless the gills are affected (Dow, et. al., 1975).

Neither of these diseases appear to be serious contributions to

natural mortality in the wild, but under more densely-populated conditions

such as in lobster pounds they can be much more serious, the gaffkaemia

even becoming epidemic.

Environmental factors, such as temperature, salinity, and oxygen

appear to exert relatively minor influence on natural mortality under

natural conditions. Lobsters can acclimate to changing conditions of

temperature, salinity, or oxygen if the rate of change is not too rapid.

McLeese (1956) determined the ultimate lethal level of temperature to

304

be 32.OOC at optimum levels of 30 o/oo for salinity and 6.4 mg/1 for

oxygen; the minimum lethal level of temperature to be 1.80C for lobsters

acclimated to 170 C; the minimum lethal level of salinity to be 8..0 o/oo

at 150C and 6.4 mg/1 of oxygen; and the minimum lethal level of oxygen

to be 0.44 mg/1 at 50C and 25 o/oo salinity. Once caught and stored

alive in floating crates or cars, or in pounds, the lobsters may be

subjected to changes in their environment which occur at a rate too

rapid for them to become acclimated. Heavy commercial losses are then

likely to occur.

Long-range changes in the average conditions under which the lobster

exists may have important effects on its overall abundance. Dow (1969,

1977) has shown lobster landings to be correlated with annual mean sea

surface temperatures (at Boothbay Harbor) 5,.,-.6,-,_-and 7 years earlier

(correlation coefficient = 0.86).

Pollution is not generally an important contributor to lobster

mortality. Domestic pollution (sewage)'would be a threat only in areas

of high-volume@ dumping, where the oxygen content of the water near

bottom might become depleted. Industrial pollution is not generally

a problem in Maine, except for the threat of, and occasional occurrence

of, oil spills. in such infrequent circumstances, economic losses are

more likely to occur from the off-flavoring and consequent unmarket-

ability of lobsters than through actual mortality.

Growth is extremely important to the availability of lobsters to

the market. Thomas (personal communication) stated that 86% of the

available legal-size lobsters are removed by the fishery each year.

305

In addition, he has found that 77% of this annual catch is made up of

lobsters that have just become legal by virtue of growth through a recent

molt. It is evident that growth must be sustained at or above the

current rate in order to maintain the flow of lobsters to market. Krouse

(1977b) stated that 5.2 years were required for a lobster at Jonesport

to grow to the minimum legal size of 81 mm (3-3/16 in.) and that this

period probably varied from 5 to 7 years for the Maine inshore resource.

Thomas 1973) gave an average of 6.8 years for the whole Maine coast.

The calculated growth curve for inshore Maine lobsters from 0 to 20 years

of age is shown in Fig. D-3-8 (-Curve 1). Using probability modes from.

commercial length-frequency data, Thomas (1973) calculated an increase

of 8% in carapace length from premolt to po stmolt sizes, while laboratory

and tagging studies have shown average molt increase of 14% in length and

40 to 50% in weight.

The availability of lobsters to the fishery decreases with the onset

of colder weather. Some fishermen attribute this to an offshore movement

of lobsters but the evidence indicates a closer relationship with the

reduced activity of lobsters in lower temperatures, Since all lobsters

taken in Maine are caught with baited traps, catchability is directly

dependent on the activity of the lobster. McLeese and Wilder (1958)

0
found that activity of lobsters increased from 2 to 10 C and from 20
to 250C, but was constant between 10 and 20 0C. As inshore waters cool

down in late fall, the activity and therefore the catch of lobsters

decreases; but fishermen find that in the deeper offshore waters, where

temperatures are slower to decline and remain higher through the winter,

306

lobsters are still sufficiently active to be trapped, although in

smaller quantities than are taken in the inshore fishery.

Another important reason for the late-season decline in catch

due to unavailability of lobsters is the marked decline in abundance

as the newly-molted lobsters that have just attained legal size are

caught in the highly intensive summer fishery. This important molt

takes place mostly during July and August and, as described above, an

estimated 77% of the annnal catch is made up of these new recru its

to the fishery.

The combined effects of these two seasonal factors on the monthly

catches are shown in Table D-3-5, Figure D-3-9.

Maine's Problems in Availability of Lobsters

Maine's problems in the availability of lobsters to the fishery

are largely those concerning the size, nature, and stability of the

natural stocks of lobsters.

1. The fact that 86% of the legal sized lobsters are caught each

year and that 77% of this catch depends upon a single molt and growth

from sublegal to legal should concern the fishing-industry and the general

public far more than it apparently does. The failure of a single year-

class of lobsters, for whatever reason, would mean the nearly total

collapse of the fishery for at least 1 year and possibly several. It

is hard to believe that such has not occurred as yet, since wide

fluctuations in year-class strength are very common in marine resource

species.

307

2. There is serious doubt that the resource can sustain the

presently very intensive fishery for very long on the basis of the

limited breeding stock available. Since only a small percentage of

females have an opportunity to breed before being caught, the proposed

increase of minimum size to 89 mm (3 1/2 inches) in order to increase

this percentage should beconsidered seriously.

3. The extremely intense fishing effort expended and the high

percentage of the stock taken in the annual catch should be a matter

of great concern. As stated in the American Lobster Fishery Management

Plan (Anon., 1978), "Increasing the minimum size limit to near the size

at which the majority of female.lobsters are mature will increase the

abundance of brood stock and, depending on the stock-recruitment re-

lationship, may benefit recruitment. However, increasing the minimum

size limit will not affect (sic)-an increase in the number of size

groups in the exploited phase. The number of size groups present is

affected by the fishing mortality rate, given available information

on lobster growth and natural mortality rates. So long as the fishery

operates essentially on one size group which is subject to natural

failure of recruitment, as is presently the case in the inshore areas,

the stability of the fishery will be thre atened. Even with a substantial

increase in the.minimum size, this aspect of the overfishing problem

may continue in the absence of a program to control fishing mortality"

(emphasis added).

308

Bibliography and Literature Cited

Ache son, James M., 1975. The lobster fiefs: economic and ecological
effects of territoriality in the Maine lobster industry. Human
Ecology: Vol. 3, No. 3, pp. 183-207.

Anonymous, 1972. An analysis of the Maine commercial lobster catch.
Me. DMR, Lobster Informational Leaflet No. 1. 14 pp.

*Anonymous, 1976. Maine Coastal Inventory, Fish and Wildlife #1.
Maine State Planning Office, 29 maps.

*Anonymous, 1978. American lobster fishery management plan. Lobster
Sub Board of the Northeast Marine Fisheries Board, 178 pp.

Anonymous, 1979. Trap limits. Me. DMR, Research Reference Document
74/2, 6 pp.

*Dow, Robert L. 1964. Supply, sustained yield, and management of the
Maine lobster resource. Comm. Fish. Rev: Sep. No. 716, Nov. 1964,
pp. 19-26.

*Dow, Robert L., 1969. Cyclic and geographic trends in seawater
temperature and abundance of American lobster. Science: 164,
30 May, 1060-1063.

*Dow, Robert L. 1974. American lobsters tagged by Maine commercial
fishermen, 1957-59. U.S. Fish. Bull: 72, 622-623.

*Dow. Robert L., Frederick W. Bell, and Donald M. Harriman, 1975.
Bioeconomic relationships for the Maine lobster fishery with
consideration of alternative management schemes. NOAA Tech.
Rept: NMFS SSRF-683, 44 pp.

*Dow. Robert L., 1977. Effects of climatic cycles on the relative
abundance and availability of commercial marine and estuarine
species. J. Cons. Int. Explor. Mat: 37 (3)r 224-280.

Flowers, J.M., and S.B. Saila, 1972. An analysis of temperature
effects on the inshore lobster fishery. J. Fish. Res. Bd. Can:
Vol. 29, No. 8, pp. 1221-1225.

Herrick, F.H., 1896. The American lobster: a study of its habits and
development. Bull. U.S. Fish. Comm: 15, pp. 1-252.

Cited in text.

309

Krouse, Jay S., 1973. Maturity, sex ratio, and size composition of the
natural population of American lobster, Homarus amemcanus, along
the Maine coast. NOAA, NMFS, Fishery Bulletin: Vol. 71, No. 1,
pp. 165-173.

Krouse, Jay.S., 1976. Incidence of cull lobsters, Homarus conericanus,
in commercial and research catches off the Maine coast. NOAA,
NMFS, Fish. Bull: Vol.. 74, NO. 4, pp. 719-724.

*Krouse, Jay S., 1977a. Lobster tagging study. Me. DMR, Lobster
Informational Leaflet #5, Dec. 1977. 13 pp.

*Krouse, Jay S., 1977b. Completion report of lobster tagging project.
NOAA, NMFS Comm. Fish. Res. and Der. Act Project #3-228-R. Me. DMR.

Krouse, Jay S., 1977c. Facts behind the lobster escape vent law.
Me. DMR. Lobster Informational Leaflet No. 4. 10 pp.

*Krouse, Jay S., 1978a. Summary of lobster, Homarus onericanus, tagging
studies in American waters (1898-1978). Paper given at Workshop
on Lobster Management Biology, St. Andrews, N.B., Can. Oct. 24-26,
1978. Mimeo. copy, Me. DMR, 14 pp.

Krouse, Jay S., 1978b. Effectiveness of escape vent shape in traps for
catching legal-sized lobster, Homarus canericanus, and harvestable-
sized crabs, Cancer borealis and Cancer irroratus. NOAA, NmFS,
Fishery Bulletin: Vol. 76, No. 2, pp. 425-432.

Krouse, Jay S. and James C. Thomas, 1975. Effects of trap selectivity
and some population parameters on size composition of the American
lobster, Homarus wnericanus, catch along the Maine coast. NOAA,
NMFS, Fishery Bulletin: Vo. 73, No. 4, pp. 862-871.

*McLeese, D.W., 1956. Effects of temperature, salinity, and oxygen on
the survival of the American lobster. J. Fish. Res. Bd. Canada:
13 (2), 247-272.

*McLeese, D.W., and D.G. Wilder, 1958. The activity and catchability
of the lobster Homarus onericanus in relation to temperature,
J. Fish. Res. Bd. Can.: 15 (6), pp. 1345-1354.

*Thomas, James C., 1973. An analysis of the commercial-lobster Homarus
americanus fishery along the coast of Maine, August 1966 through
December 1970. NOAA Tech. Rept: NMFS ssrf-667, 57 pp.

*Thomas, James C., 1978. Measures of effort. Paper given at U.S.-Canada
Lobster Workshop, St. Andrews, N.B., 24-26 Oct. 1978. DMR. mimeo
copy, 13 pp.

310
TABLE D-3-1.
CATCH OF LOBSTERS IN MAINE, 1880-1978

Total No. of Total No. Average Total
Catch Licensed of Traps Price Landed
Lobster Fished Per. lb. Value
(millions Fishermen (Mil.lions
of lbs.) (Thousand) (Thousands) of $)
1880 14.2 2.8 104 .021 0.3
1886 23.0 - - -
1887 22.9 1.9 109 .022 0.5
1888 21.7 2.0 107 .023 0.5
1889 25.0 2.1 121 .020 o.5
1890 20.0 - - -
1892 17.6 2.6 153 .039 o.7
1894 - - 200 -
1897 11.2 2.4 234 .074 0.8
1898 12.3 3.1 279 .076 0.9
1899 12.7 3.1 335 .076 1.0
1900 14.4 3.1 327 .072 1.0
1901 14.0 2.8 304 .072 1.0
1902 14.3 2.5 289 .085 1.2
1903 13.1 2.6 268 .093 1.2
1904 12.1 2.5 - .088 1.1
1905 11.1 2.6 254 .125 1.4
1906 15.0 2.7 304 .109 1.6
1907 17.4 - - .108 1.9
1908 17.6 - - .088 1.6
1909 17.0 - - .105 1.8
1910 19.9 - - .107
1911 16.2 -
- .126 2.0
1912 16.3 - - .125 2.0
1913 8.1 - - .199 1.6
1914 8.6. - - .192 1.7
1915 11.5 - - .203 2.3
1916 10.2 3.3 - .219 2.2
1919 5.8 3.1 - .247 1.4
1924 5.5 - 154 .321 1.8
1928 7.1 211 .283 2.0
1929 6.6 - .295 2.0
1930 7.8 205 .258 2.0
1931 5.4 - 168 .245 1.3
1932 6.1 2.9 208 .180 1.1
1933 5.9 3.0 180 .169 1.0
1934 5.4 2.9 183 .164 0.9
1935 7.7 3.1 185 .229 1.8
1936 5.1 - 185 .184 0.9
1937 7.3 - 186 .189 1.4
1938 7.7 '3.6 258 - -
1939 6.6 3.7 260 .156 1.0
1940 7.6 3.7 222 .166 1.3
1941 8.9 3.6 194 .177 1.6
1942 8.4 3.5 187 217 1.8
1943 11.5 4.2 208 -256 2.9
1944 14.1 4.9 252 .286 4.0
,1945 19.1 6.2 378 .401 .7.7
1946 18.8 6.6 473 .383 7.2
1947 18.3 S..3 516 .373 6.8
1948 15.9 5.3 459 .404 6.4
1949 19.3 5.4 462 -348 6-7

311

TABLE D-3-1. (continued)

CATCH OF LOBSTERS IN MAINE, 1880-1978

Total No. of Total No. Average Total
Catch Licensed of Price Landed
Lobster Traps Per. lb. Value
(Millions Fishermen Fished (Millions
of lbs.) (Thousands) (Thousands) (Dollars) of $)
1950 18.4 5.2 430 .349 6.4
1951 20.8 4.6 383 .348 7.2
1952 20.0 5.0 417 .425 8.5
1953 22.3 5.5 490 .377 8.4
1954 21.7 5.8 488 .373 8.1
1955 22.7 6.o 532 .384 8.7
1956. 20.6 5.9 533 .443 9.1
1957 .24.4 6.1 565 .367 9.0
1958 21.3 6.2 609 .490 10.4
1959 22.3 6.5 717 .504 11.2
1960 24.0 6.6 745 .457 11.0
1961 20.9 6.5 752 .532 11.1
1962 22.1 5.7 768 .507 11.2
1963 22.8 5.7 731 .553 12.6
1964 21A 5*8 754 .664 14.2
1965 .18.9 5.8 789 .751 14.2
1966 19.9 5.6. 776 .749 14.9
1967 16.5 5.4 715 .824 13.6
1968 20.5 5.5 747 .727 14.9
1969 19.8 5.8 805 .808 16.0
1970 18.2 6.3 1,180 ..1.000 18.2
1971 17.6 6.7 1,278 0.994 17.5
1972 16.3 7.0 1,448 1.14 18.6
1973 17.0 7.9 1,172 1.37 23.3
1974 16,5 10*5 1,790 1.41 23.2
1975 17.0 10.5 1,771 1.62 27.5
1976 19.0 9.0 1,754 1.54 29.2
1977 18.5 8.9 1,700 1.57 32.1
1978 19.1 1.75 33.9

TABLE D-3-2.

ANNUAL CATCH OF IbBSTERS IN MAINE BY COUNTIES, 1969-1978

(Millions of Pounds)

1969 1970 1971 1972 1973 1974 1975 1976 1977 1978

York 1.1. 1.0 1.1 1.0 1.1 1.1 1.1 1.0 1.0 0.8
Cumberland 2.9 2.9 3.0 2.6 2.4 2.4 2.7 3.1 3.2 3.6
Sagadahoc 0.5 0.5 0.5 o.5 0.4 0.5 o.4 0.4 0.5 0.5
Lincoln 2.3 2.2 2.1 1.8 1.7 1.9 1.9 @.3 2.4 2.3
Knox 5.3 4.7 4.4 4.4 4.6 .4.5 5.2 5.2 5.1 5.4
Hancock 5.3 4.6 4.3 4.0 4.7 4.0 3.9 4.6 4.2 4.5
Washington 2.6 2.2 2.2 1.9 2.2 2.1 1.9 2.5 2.0 2.1

Total 19.8 18.2 17.6 16.3 17.0 16..5 17.0 19.0 18.5 19.1

4W W1

TABLE D-3-3.

SOME TOTAL ESTIMATES FOR LOBSTER FISHERY IN MAINE,(Thomas, 1978)
CATCH 1967 1968 1 1969 --19 70 lu/1 --1972- - 1979 1976 1977 - - fg-7 T 1979 19
IN
POUNDS 16,491,195 2Q506,50019838,385 18175,815 17
560620 16259,670 17,046,855 16,460,325 17017,411 19,OOtO53 18;487,138 19,130;459

CATCH
N
NAERS lq975,589 17232.353 16;53t987 15273,794 14,633i850 8 13@49@070 14,3Oq345 16,102,587 15,535,410 16,212.253
13,549,725 14,325,P8
TO-f-A-L I --
VALUE 13,247,026 14,696,325 15,935,752 16P43,556 17235,424 16,784,175 21,782P93 22,666@677 2756q2O6 27,688J643 29.024.8.07 3Z382.208

TOTAL
TRAP
HAULS 27,03@746 34,177,500 32521,943 3Q8O6466 32,51@667 2622q274 31,56q250 2@98A139 3@034,822 30,64@860 34,881.392 32,983,550

TOTAL
BOAT
DAYS 194A29 215,216 240,430 18@051 208)04 157,793 180,462 165,182 187,595 187,763 195.342 185,373

TOTAL
234@257 227,730 24@031 263,757
DAYI 240,396 262P30 29QBOO 227881 26t397 20@708 266,50C 257962

TOTAL
MAN
H6URS 1,76@595 1,87@120 2,01 R558 1,735,658 1,948,582 1,502)87 1,857,988 1.641,371 1,894@085 1.928,454 2.027.096 21020,112
[3

TABLE D-3-4.

MAINE LOBSTER POPULATION PARAMETERS
I

Parameter Reference Calculated or Estimated Values

MSY (Equilibrium Yield) Dow (pers. comm. in 10,000 metric tons (22.3 million pounds).and
Anonymous, 1978) optimal level of effort of 800,000 traps.

Dow (1976) In years with same water temperature (1958-1973),-
catch declined 1000 metric tons per increase of
175,000 traps.

Dow (1964) Available abundance fluctuates �,5% with each
degree (F) of April-May temperature change.
4@1

Yield per Recruit Thomas (1973) Most advantageous if size at first capture were
at least 3 1/2 inches (89mm) carapace length, age
8 years, yield in weight per recruit of 355 to 440
grams. (See his Fig. 18, curve "F", and Table 11).

Age at First Harvest Thomas (1973) Average for whole coast of Maine: 6.8 years.
(Actual) Krouse (1977a) 5.2 years at Jonesport, probably 5 to 7 for inshore
Maine.

TABLE D-3-4. (continued)

Age at First Harvest Thomas (pers. comm. 14 years (5.3 inches, 135 mm CL)
(Optimum: to provide in Anonymous, 1978).
maximum yield per
recruit).

Anonymous (1978) 13 years (5.1 inches) or 6.4 to 13.2 years
depending upon various combinations of natural
and fishing mortalities. (See Table 23, 24).

Estimate of Annual Dow (1964) 1947-1956: 23 to 28 million pounds.
Available Legal 1951-1963: 25 to 28 million, pounds.
Lobster Supply.

Ln
Mortality: Instantaneous Thomas (1973) 0.02 (2.0%) to 0.35 (29.3%)
Natural.

Instantaneous Fishing Thomas (1973) 0.79 (54.6% to 2.50 (94.5%)

Instantaneous Total. Thomas (1973) 1.14 (67.9%) to 2.92 (94.6%)

Most plausible inter- Thomas (1973) Instantaneous Natural: 0.10 (10%)
pretation.of data. Fishing: 2.30,(90%)

316

TABLE D-3-5.

CATCH OF MAINE LOBSTER BY MONTHS

Millions of Pounds

1975 1976 1977 1978

Jan. 6.7 0.6 0.4 0.3
Feb. 0.2 0.1 0.1 o.2
Mar. 0.2 0.1 0.2 0.1
Apr. 0.4 0.5 0.4 0.4
May 1.2 1.0 1.2 0.8
June 0.8 1.0 0.8 o.7
July 1.6 2.1 2.0 2.0
Aug. 2.4 3.6 3.3 4.3
Sept. 2.8 3.7 3.6 4.0
Oct. 2.9 3.2 3.1 2.9
Nov. 2.6 2.2 2.4 2.2
Dec. 1.2 0.9 0.9 1.3

Total 17.0 19.0 18.5 19.1

4" IN im Imp aw a" *0 .00 Jo ON wo Am fal P"

FIGURE D-3-1
TOTAL LOBSTER LANDINGS, TOTAL VALUE AVERAGE PRICE PER POUND
36 MAINE IB80-1978 -1.80

34 - 1.70.

32 - 9
1.60
A-6
30-
-1.50

28 -
1.40

26 -
-1.30

0 U) 24 - t
-1.20
<
Z
0. 22 7v -1.10 0
a-
-'o
C) 20 -
:)0
H LJ
oil
18 It No
-0.90 U)
al LLI
LL 16J C)
O-E@o E
0 U) CL
(n 0
2 z 14- POUNDS,,,, -070 Lu
0 Fro %I&
0 12- -0.60
6 Ld
10 c"b
V. -0.50

-0.40
C'o V
0
DOLLARS
6
PE R -0.30
POUND TOTAL
4
c"'; -0.20
04! DOLLARS.
2 -0.10
01fill[ it-fill 11 oil I II III III [fill 11 IT 1 111) Irg-i-nip Ili I-my I- T11 111111 11 Ili 11111 1111111 111 1111ITIVIF 0.00
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980

FIGURE D-3-2
TOTAL LOBSTER LANDINGS, TOTAL NUMBER OF FISHERMEN, TOTAL NUMBER OF TRAPS
MAINE IBBO- 1978

26-

24 -

Li-
0 z 22 - POUNDS-,,,,
cf) w -
20- 2.0

< Ld 18 1.8
%
D U)
C) 16 -1.6 co
a_
0 <
14 -1.4 ir

0
12 - TRAPS -1.2 lJL
0 0
10- -1.0
cn Cf)
L

z
L

0 :D 8
0
6 -0.6 =-j

'00
4 0 0 04
FISHERM N
2 0--@O-ot;a'-C-o coop -0.2
0 1113114res. iij., 111FIF-1116111 11 Plit 611111 1113 9111 111151111 J1111 fill$ If l[TTI-711 loll jil 0.0
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980

FIGURE D-3-3-

ANNUAL CATCH OF LOBSTERS IN MAINE BY COU NTIES 1969 -1978
6[
KNOX

HANCOCK

0 CUMBERLAND
0-
LL 3-
0

z LINCOLN
0
2- WASHINGTON

YORK

-SAGADAHOC
0 L i
1969 1970 1971 1972 1973 1974 1975 1976 1977 1978

700 690 680. 670

450-
WASHINGTON.

-HANCOCK

WALDO

KNOX

IL
LINCO. 0 a
SAGADAHOC..."'
44
CUIVIBERLA@. ..I lop

YO R K

700 .690 681, 670

FIGURE D-3-4. State of Maine map with county designations.

321

Figure D-3-5

TRAPS PER BOAT IN MAINE LOBSTER FISHERY TH074AS ;---78

1978
COAST WIDE
40- n- 340 (BOATS

0
co

z
Uj

c'-2G-

10- -4

L-1 U U
0 100 200 300 400 500 600 700 000 c'00 >
goo 10C)o
99 199 2 9 9399 499 599 6-99 799 099
NUMBER OF TRAPS

FIGURE D-3-6
LOBSTER CATCH-EFFORT 1897-1976 (THOMAS 1978)
12-
log Y-1,P4797,221629 fog OXI-.02714 log JOX4
10 1
11- 1957, -1900 P. .936

1955.
10- 953- 1959, 1963
1 -1962
1964- :1904
1961
1961. 1956. -1968
9- 1952- 660969
1945- 1944- 1976
1946 -1906 1978
1977
1950.
8- -1970
1971
-1967 .1973
z 7- -1948 -1972 11174 1976
0 1906.
1902- -1900
u 1901.
6- 1903-
-1899 IQ
uj Ta 1905
1943 1,90.4
z 5- 1897

u
4- 1941- 1930
1942. 1940
u 1935. - - -1938
1937- 1129
3- ..1939
-1932
1924 1933
1934
2- 193 '1936

5' lb 11 1'2 1'3 14 1'5 1'6 1'7 1'8 1'9
EFFORT, IN NUMBER OF TRAPS(10 5
@26 28

323

Figure D-3-7.
CATCH PER UNIT OF EFFORT IN LOBSTER FISHERY (THOMAS 1978)

7 .; LL IL4 I A
N --3 3 1

7..

Tk-

#--835

.32-

.2@

.26-

.22-

--s 16 466

52-

so-
tz
48

44-

v -.207,007 X
it --.712

J7-

33-

19172 19173, 19174 19175 19176 19@7 19'78 119'7.9 19'80
19 1969 1970 1971
YEARS

260 -

240 -

220 -
200 - 10
180
160 MAINE
X 4
140 5
W

to 120

4 100 41.

0
1 2' 3 4 3 6 7 8 9 10 11 12 13 14 15 10 17 10 19 20

A G C

Figure D-3-8. Band of lobster growth curves (von Bertalanffy) examined in yield relationships.

325

FIGUPX D-3-9.

CATCH OF MAINE LOBSTERS BY MONTHS, 1975-1978

5.0

4.0
z

0
al
U- 3.0
0

1975
z 2.0 -
/11976

1977
1.0 - 1978

0.0 r-,.n a-,i, U
JAN FES MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC

326 1
I
I
I
I
I
I
ELEMENT D-4: I
A CHARACTERIZATION OF THE I
. SCALLOP FISHERY OF MAINE
I
by
.I Clement J. Walton I
I
I
I
I
I
I
I
I

327

Distribution:

Sea scallops (Nacopecten mageZZanicus), range from the northern

shore of the Gulf of St. Lawrence and Newfoundland to Cape Hatteras.

The north-south distribution of sea scallops, and probably inshore

distribution south of Cape Cod, is temperature limited. Scallops tend

to be found in deeper water in the southern portion of their range and

populations are sparse or scattered at the extremities of the range.

Scallops are found along the entire Maine coast and harvestable

beds occur close inshore at depths of only a few fathoms. This species

prefers hard bottom such as rocks, cobble, gravel, sand and firm mud and

is only rarely found on soft mud. Spatial distribution may also be

limited by hydrography and scallops appear to be more abundant where.there

are currents near the bottom.

The Maine Coastal Inventory map series, 1-1 through 11-2, prepared

by the Maine State Planning Office, details a number of inshore scallop

producing areas. These data provide a qualitative sketch of some of

the scallop beds and caution should be exercised in their interpretation

since they were based on anecdotal information.

Availability:

The availability of scallops within the territorial waters of the

state is limited by a regulation which imposes a closed season from

April 16 to October 31 each year. The closed season does not apply

outside the territorial waters of the state as defined in the Maine

328

Marine Resources Laws and Regulations (�6722). A minimum size limit of

three inches (longest diameter) with a 10% tolerance is provided for

scallops under �6721:1,2; this restriction is usually enforced for

landings and thus will apply to scallops taken outside the territorial

waters but landed in Maine ports.

There are a number of area and gear restrictions which also affect

availability of scallops. These include:

A maximum combined drag size of 81 in Blue Hill Bay. �6723.

A prohibition against the use of otter trawls for scalloping
in the Penobscot River. �6724.

Regulations of the Commissioner of the Department of Marine

Resources which may affect the taking of scallops include:

Prohibitions against drag seines in the Damariscotta River
'Sect, 9, IV); Georges River ISect, 9, VI; Sargentville
Harbor (Billings Cove) (Sect. 32).

Prohibitions against beam trawls in Sedgwick Harbor (Sect. 34).

A closure of areas of the Harrington River and Bay and Pleasant
River to scallop dragging from April 15 through December 1 each
year (Chapter C, Sect. 3).

A maximum combined drag size of 4' for scalloping in Gouldsboro
Bay, Hancock and Washington Counties (Chapter C, Sect. 4).

Regulations against the taking of marine mollusks from polluted

areas have not been interpreted as including scallops although this

could be enforced and could preclude the taking of scallops in a number

of inshore areas.

Closures to the taking of shellfish because of paralytic shellfish

329

-poisoning (PSP) have not included scallops because the portions consumed

are not toxic. If consumption patterns change and a market for whole

scallops develops, such that muscles and viscera are eaten, the PSP

closures would be enforced for scallops. This could affect the

harvesting of scallops outside the territorial waters of the state.

The distribution, abundance and size range of scallops affect their

commercial availability. Beds close to ledges and shoal areas frequently

cannot he harvested by conventional drag and are vulnerable only to SCUBA

divers. Thinly dispersed populations and those with a sizable proportion

of small (less than three inch diameter) scallops are not usually

profitable to harvest.

The historical production data presented in Table D-4-1 must be

interpreted with caution; some Maine boats started fishing offshore in

the 1930's but the landings prior to 1950 were primarily representative

of the inshore fishery. Since 1950 the offshore harvest has become a

significant proportion of the total landings. An allocation of landings

to inshore and offshore fisheries has been made by various authors

(Dow, 1956; Baird, 1956, 1967) by assuming that landings made during

the closed season were entirely offshore harvesting. This method is of

questionable accuracy for open season landings since they represent

combined inshore and offshore harvesting and available data do not permit

accurate allocation of catches to inshore and offshore fisheries.

Commercial scallop fishing apparently started in the midcoast area

330

TABLE D-4-1.

MAINE SCALLOP LANDINGS
(shucked meats in thousands of.pounds)

YEAR TOTAL YEAR TOTAL YEAR TOTAL

1887 220 1918 - 1949 509
1888 181 1919 73 1950 525
1889 306 1920 - 1951 677
1890 - 1921 - 1952 1,496
1891 - 1922 - 1953 1,697
1892 117 1923 - 195.4 708
1893 - 1924 296 1955 1,114
1894 - 1925 - 1956 970
1895 - 1926 1957 745
1896 - 1927 - 1958 394
1897 170 1928 326 1959 1,134
1898 71 1929 359 1960 1,875
1899 53 1930 436 1961 2,740
1900 174 1931 587 1962 2,169
1901 219 1932 608 1963 1,186
1902 126 1933 1,073 1964 917
1903 137 1934 - 1965 414
1904 142 1935 743 1966 320
1905 628 1936 - 1967 188
1906 561 1937 - 1968 220
1907 521 1938 793 1969 152
1908 952 1939 395 1970 180
1909 1,858 1940 455 1971 387
1910 2,027 1941 316 1972 967
1911 1,462 1942 131 1973 804
1912 1,857 1943 227 1974 445
1913 777 1944 101 1975 1,594
1914 850 1945 105 1976 629
1915 - 1946 137 1977 395
1916 587 1947 507 1978 908
1917 - 1948 454 1979 1,644

331

during the 1880's and expanded to the region between Mount Desert Island

and the Sheepscot River (Baird, 1956). The early fisheries were limited

to shallow (<25 fathoms) scallop beds due to the nature of the gear and

fishing vessels. The addition of powered winches and motorized vessels

to the fishing fleet extended the area that could be fished and allowed

the deeper scallop beds to be harvested. The commercial fishery

concentrated on the inshore grounds east of Penobscot Bay prior to 1950.

The inshore closed season, mid-April through November, was suspended

during World War II to increase food production. A closure from April 1

through October 31 was re-established in 1947 and subsequently modified

to the present mid-April through October closure (Dow, 1956).

Landings between 1945 and 1970 were primarily (66 to 100%) scallops

from six to nine years of age with six year olds predominating (Dow, 1971).

The mean shell diameter of scallops in the commercial harvest has

apparently declined since the 1920's. This probably reflects a gradual

-decrease in the mean age of the harvested scallops and can be associated

with the expansion in fishing effort (number of boats in the fishery).

Major scallop producing areas have traditionally included the

inshore waters from Penobscot Bay to Mount Desert Island, eastern

Penobscot Bay in the vicinity of Castine, Jonesport and the Harrington

and Addison Rivers. Some inshore scalloping has also occured in Casco

Bay and the Sheepscot, Damariscotta and Piscataqua Rivers.

Offshore areas are not as completely documented but localized

332

fisheries have occurred in the vic inity of Jeffreys Ledge and Cashes

Ledge. Other areas may include Platts Bank and off Machias Seal Island.

It is difficult to-quantify historical production for these areas si nce

data are not available and production peaks tend to coincide with the

appearance of one or more successful year classes in a given area.

The sea scallop has been characterized by irregular abundance in

most areas of the coast and this probably results from biological and

environmental factors. This variability has tended to g enerate cyclic

fisheries in which the discovery of a large population of harvestable

scallops leads to a rapid expansion of the fishery and the subsequent

depletion of the stock. This variability occurs in both,inshore and

offshore areas; the 1975-76 scallop fishery in-the Castine area of

'Penobscot Bay and the 1979-80 fishery off Jeffreys Basin are examples

of the rapid expansion of harvesting of newly discovered scallop beds.

Assessment of the scallop stocks of the Gulf of Maine has been a

difficult problem since the landings have exhibited large fluctuations

due to social and economic factors (e.g., competing fisheries such as

for shrimp; market demand, price, etc.) and changes in population@

abundance. Significant increases in landings have been produced by

successful year classes of scallops such as,the 1972 year class on

Georges Bank and in the Middle Atlantic Bight (Serchuk et aZ., 1979)

and the 1975 year class off southern Maine.

Successful year classes are one source of variations in abundance.

333

The scallop is enormously fecund and a five or six year old female can

produce two million eggs (Posgay, 1979). There is no biological evidence

that different stocks occur within the Gulf of Maine and the spatial and

temporal distributions of scallop populations are probably a result of

their reproductive biology. Spawning occurs in late summer or early

fall and the larvae are pelagic for three to four weeks; thus the progeny

are not apt to settle in the vicinity of the parental beds and the

distribution of scallop spat is determined by currents and environmental

conditions in the area of spatfall.

Scallops generally occur in high salinity waters; survival may be

limited in some shallow estuarine areas where coastal runoff is

occasionally high. Spawning and/or larval development can be prevented

or delayed by very low summer temperatures and this probably causes small

or patchy distributions of scallop sets in the northern portion of their

range (Medcof and Bourne, 1964). Mortalities may also be induced by

exceptionally high summer temperatures (Dickie, 1958).

The relationship between temperature and commercial landings of

scallops is not clear. Dow (1971a) reported a negative correlation

(r = -.91) between Boothbay Harbor mean annual seawater temperature and

scallop landings lagged seven and eight years. Dow (1971b) also reported

a strong (r = -.7) negative correlation between these mean annual

temperatures since World War II and landings with a six year lag.

Sutcliffe, et al. (1977) reported a high positive correlation (r = +.88

334

for November mean seawater temperatures at Boothbay Harbor and New

England scallop landings lagged by five years. These authors also

reported a very high positive correlation (r = +.79) for St. Andrews

temperatures in November and New England scallop landings with a six

year lag.

Populations are also limited by predation and mortalities may be

high, especially in larvae and juveniles. Starfish (Asterias vuLgaris)

feed on juvenile scallops (Welch, 1950; Dow, 1969). Adult and juvenile

starfish are major predators on scallop spat and may be the most

important factor influencing spat survival (Naidu and Scaplen, 1979).

Predators on juvenile scallops include cod (Gadus morhua), plaice

(HippogZossoides pLatessoides), And wolffish (Anarhichas Lupus),

Medcof and Bourne, 1964). Merrill and Posgay (1964) reported an annual

natural mortality of about 10% for sea scallops.

Fishing mortality can be significant in some areas and mortalities

may also be induced by dragging activities due to burial in soft bottom

areas, breakage of small scallops in the dredge or during culling and

dumping operations. Some small scallops may also die from exposure to

low air temperatures during the Maine winter fishery.

Weather conditions also affect landings of scallops. Strong winds,

high seas and low temperatures reduce fishing effort and cumulative

effects may be deduced from monthly landings data. Larger vessels

fishing offshore beds may not be adversely affected by sea conditions

335

which preclude fishing by the smaller vessels in inshore waters.

Maine appears to have a greater proportion of small vessels

(mostly concentrated in the inshore fisheries) than is found in other

coastal states where offshore fishing is the rule. This suggests that

the Maine fleet may be more vulnerable to adverse weather conditions.

Rising fuel prices may also have a greater proportional impact on the

Maine fleet since small vessels operating a day-trip fishery are

probably less efficient than larger vessels working offshore beds.

Harvesting:

The available data are inadequate for the development of

comprehensive social and economic profiles of the scallop harvesting

sector. Lobstermen and the owners of small draggers appear to

participate in the inshore scallop fishery although the value of the

scallop fishery as winter employment for lobstermen is probably
insignificant.* Switching between different winter fisheries is quite

common and probably depends upon the fishermen's evaluation of the

prospects for the different fisheries in the immediate future. Rigging

for scallop dragging is easier and less expensive than rigging for

bottom trawling for shrimp or groundfish and this may affect the

switching process. Most scallop vessels are used for some other type

In 1976 Malne issued 9,041 lobster licenses and 604 scallop licenses.
If all scallopers were lobstermen the scallop fishery would employ
less than 7% of the licensed lobstermen in winter.

336

of fishing. The allocation of capital and operating costs for a typical

inshore scallop fishing vessel could be estimated as a proportion of the

annual costs of operating a lobster boat. This proportion could be

based on the relative time spent lobstering vs scalloping; with the

present five and one half month scallop season this should be something

less than 5/12 of the costs of operating a lobster boat.

Wilson and Peters (1978) provided some data on the characteristics

of vessels in the scallop fishery. The results of their census are

summarized in Table D-4-2 and the authors estimated a response of about

60%. It should be noted that some of the vessels that reported shellfishing

activity may have been dragging for mussels and/or surf clams (York-

Cumberland counties). These census data are an estimate since there were

192 vessels reporting shellfishing activity in 1977 and 440 scallop

licenses were purchased.

The census data suggest that almost 92% of the vessels owning

scallop drags are less than 46 feet in length and therefore vessel

capital investment and operating costs could reasonably be based on

lobster boat characteristics. Winter weather conditions limit the

number of days that scallops can be fished during the inshore open

season and therefore not more than 25% of the annual investment and

expenditures for the operation of an average lobster boat should be

attributed to vessels in the scallop harvesting sector. Capital

investment involved in rigging the average lobster boat for scallop

337

TABLE D-4-2.

MAINE FISHING VESSEL CENSUS DATA: 1977

Vessel Characteristics: Vessel length
461 461-651 661+

Percentage size distribution
and number of Maine fishing 86 11 10 7 3 29-
vessels. (n=438) 1?7 '4 >4 7"' @@4

Percentage and number of
Maine vessels owning 47 1 25 51 28.6'%-'
scallop drags ,--I @76 @2 @4-

Percentage of Maine boats
which fished for shellfish
in 1977: * I

Nearshore**-Eastport to Monhegan: 63.6% 87.5% 0%

Nearshore**-Monhegan to Cape Ann: 38.2% 87.5% 0%

Jeffreys & Cashes Ledges: 9.6% 25.0% 0%

Georges Bank: 0.4% 12.5% 100%

Based on data from Wilson and Peters, 1978.

*Percentages do not sum to 100 because some vessels fished more than
one area.

**Nearshore is defined as being within 20 miles of the coast.

338

dragging should involve roughly $2,000 for gear (1979). Fuel expended

in the inshore fishery could be a significant cost item and may exceed

$2,000 for the open season.

Scallop dredge gear is enormously variable because of the

fishermen's habit of adapting the gear to fish in their particular area.

Inshore gear for gravel and rock bottom usually involves scallop drags

of three to four foot width towed singly, as doubles or triples. The

multiple dredge rigs can adapt to uneven bottom contours and will fish

better than the single wide dredge often favored for relatively smooth

bottom. For softer sand and clay bottoms, especially when smaller

scallops are abundant, small beam or otter trawls with a chain footrope

have been used. The beam or otter trawl is rate in the Maine scallop

fisherybut is occasionally used offshore and in the Penobscot Bay area.

Toothed or rake type drags are not commonly used in Maine. The number

and size of dredges towed by any specific boat are dictated by the

bottom topography and,to some extent, by the powered deck gear on the

boat and the available manpower.

The large (66 ft. +) offshore draggers usually tow two multiple

drags which may consist of gang rigged dredges, 12 or more feet in

width. Individual dredges are usually rigged with three inch or larger

steel rings and chain on the bottom and a heavy mesh nylon net bag on

the top. In areas of very rough bottom chain and rings may be

substituted for the top webbing. In sand and rocky areas the chain and

339

rings wear rapidly and gear repair costs may be quite high. There have

been relatively few technological advances in dragging gear since the

advent of powered deck gear and there seems to be little immediate

prospect for a dramatic increase in fishing power.

There is a modest recreational fishery conducted with SCUBA gear

(see Element C, Recreational Fisheries) and a small amount of commercial

harvesting by divers. Commercial harvesting by SCUBA usually involves

local sales and few landings data are collected. SCUBA gear has

obvious advantages in that it is suitable for rough bottom and scallops

can be harvested from areas which cannot be fished by dredge gear. The

disadvantages are that diving is confined to relatively shallow water

in a small area and diving time is limited.

Prices paid for scallop meats are comparatively high but the

processing is labor intensive and the return per pound of shellstock

harvested is more modest. Dow (1956) pointed out that the economic

factors involved in production are probably quite different for the

inshore and offshore fisheries. He based this conclusion, in part, on

the correlations between price and production in these fisheries.

Harvest in the offshore fishery is probably influenced by price

(r = .74 for the 1949-1955 period) whereas the inshore fishery exhibited

a negative correlation (r = -.65 for the 1949-55 period) which suggested

that production levels influenced prices.

Imports of Canadian scallops are quite large but their distribution

340

in Maine is not documented. Most imports are shucked meats, either

fresh or frozen, transported by truck through Houlton, Calais or

Eastport. There are also son'te- landings by vessel at Portland. The

import data are available through the U.S. Customs and are tabulated

in the "Blue Sheets" (NMFS Fishery Market News Report). A review of

the import data in a six month segment of these reports suggests that

the bulk of the scallops imported from Canada pass to or through

Maine. The magnitude of these imports may be surmised from the 1978

scallop imports and landings data; Maine landed 908,000 pounds and

imported 24,332,000 pounds of scallop meats. These imports probably

do not have any significant impact on the Maine scallop fishery although

they may tend to stabilize prices..

Economic conditions in other fisheries may affect the scallop

harvest, this occurs in the fishermen's decisions on whether to rig for

scalloping in the fall or to fish for some other species such as

shrimp. These effects cannotbe easily quantified with the available

data. Regressions of the number of scallop licenses against effort

(number of vessels) in.the shrimp fishery for a series of years do not

yield significant negative correlations that might be expected if

systematic switching occurred. There are a great number of lobster

boats in Maine and a majority of these are relatively inactive during

the winter; this under utilized harvesting capacity acts as a buffer to

mask the effects of switchingfrom one fishery to another.

341

Legal constraints appear to have only a moderate effect on harvesting

an d a negligible effect on abundance. A license is required for commercial

harvesting or any harvesting in excess of two bushels (four quarts of

shucked meats) per day. The license fee is modest ($25 in 1979) and it

includes the license holder's boat crew. The closed s@eason (mid-April

through October) applies only to the state's territorial waters (inside

three miles) and offers obvious advantages for the lobster fishery. This

open season covers an area fished by typically small (lobster) vessels

and is appropriately timed to permit off-season lobstermen to participate

in the scallop fishery. The closed season, of course, restricts

fishing at the time that these vessels are engaged in lobstering; this

coincidence also eliminates some gear conflicts. During warm years

lobsters tend to remain active through November and gear conflicts

between scallopers and lobstermen have occurred in such locations as

Blue Hill Bay, Penobscot Bay and the Harrington River. Such conflicts

can be averted by judicious postponement of the open season on scallops

in selected areas, e.g., the extended closure to December I each year in

the Harrington and Pleasant Rivers (Chapter C, Sect. 3).

Some conservation of the resource may be achieved through the

closed season since most scallop beds cannot sustain intensive year round

fishing. It is probable thatwithout the closed season, the average

newly discovered bed could be fished out in one year; with the closed

season it takes two years. The inshore scallop populations may derive

342

some benefit from the closures since fishing is, fortuitously,

prohibited during the spawning season although there is no evidence to

suggest that inshore abundance is related to the spawning success of

inshore populations.

Offshore scalloping is not well documented for the Gulf of Maine

fisheries. Landings data for 1979 (Richard Barnard, NMFS, personal

communication) do indicate some recent harvesting patterns and are

presented in Table D-4-3.

Area and gear restrictions, in sum, have little effect on scallop

abundance although they do affect the fishery. Limitations on the size

of drags appear to favor small vessels since they reduce the efficiency

of larger craft capable of operating with multiple drags. Some.area

and gear restrictions tend to avert gear conflicts but other restrictions

are based solely on restraint of competition. Perhaps one example of

the latter would be the prohibition of otter trawls for scalloping in

the Penobscot River (�6724). This restriction presumably arose because

of a unique situation in which a scallop bed on relatively flat soft

bottom in Penobscot Bay was harvested with great efficiency by otter

trawls with chain gear on the footropes.

The three inch size limit is probably advantageous since most of

the scallops are old enough to have spawned at least once. Shucking is

conducted aboard the boats and enforcement of a size limit is extremely

difficult since the evidence is rapidly discarded during fishing

343

TABLE D-4-3.

MAINE SCALLOP LANDINGS, 1979
(shucked meats in pounds)

COASTAL AREA
Eastern Central Western Totals
Location: (511) (512) (513)

0 - 3 miles, offshore 128,741 461,678 12,054 602,473

3 - 12 miles, offshore 0 1,903 492 2,395

Beyond 12 miles 0 32,606 67,424 100,030

Jeffreys Ledge (514) 11,012

Cashes Ledge (515) 69,646
558,777
Georges Bank (523) 292,826

Georges Bank (524) 85,263j

Total landings: 1,643,645

344

,operations. During rapid growth periods in some areas scallops can

exceed four inches prior to spawning and the size limit would confer no

advantages associated with reproduction. Serchuk, et al., (1979)

provided analytic data to demonstrate that, for most fishing mortality

rates, scallop meat yield increases as size at first capture increases.

Optimal yield for Gulf of Maine scallops would probably result if the

minimum size limit were increased from three inches (76 mm) to at least

four inches (101 mm). For Gulf of Maine scallops this increased size

limit would raise the age at first capture one additional growing

season and, at moderate to high levels of fishing mortality (F @ 0.3),

increase the meat yield by 20% or more.

Harvesting of scallops by divers has been characterized as very

efficient and doubts have been expressed about the wisdom of allowing

this method of fishing. In view of the limitations inherent in SCUBA

operations and the observed tendency for divers to operate in areas

where draggers cannot fish, and the converse, the two fisheries

generally do not compete for the same resource. Dow (personal

communication, 1978) estimated that divers take less than one percent

of the landings (see also Element C, Recreational Fisheries).

Processing:

Shucking is usually conducted aboard the fishing vessel during

dragging or while returning to port. Shells and viscera are usually

discarded on or near the fishing grounds. The recent (1979-80) scallop

345

fishery off Jeffreys and Cashes Ledges has been an exception to the rule

and shucking has been performed ashore. The meats are washed in sea

water at the time of shucking and are then dumped into pails or large

plastic bags.

Dealers receive the scallops from the boats, weigh them and then

dump them into bulk shipping containers. The scallop meats may be

washed again at this stage. Most meats are packaged in bulk containers

or plastic shipping bags in boxes for immediate truck shipment. Scallops

may be chilled by ice packed around the boxes (or snow if available).

scallop handling is practiced by a number of fish and shellfish

dealers in the state and comprises a small segment of their activities.

Few dealers arrange their operations to emphasize the handling of

scallops and only a very few operations, usually secondary dealers,

engage in the preparation of specialty products, or freezing of

scallop meats.

Wholesale dealers handling scallops must possess a wholesale seafood

license ($50 fee in 1979) and retailers are also required to have a

license ($10 fee in 1979). Sanitary standards in the processing sector

are a problem in that the Shellfish Sanitation Act does not cover scallops.

The Department of Marine Resources has not assumed responsibility for

scallop handling under the Fish Inspection Act. The U.S. Department of

Agriculture, under the pure food laws, has responsibility for monitoring

same handling practices but this has little effect on handling procedures

346

in Maine.

Sanitation practices can be substantially improved but state and

federal agencies do not have the manpower and/or funding to inspect and

enforce existing regulations at this time. Major wholesale dealers

are reasonably prudent in the observance of sanitary standards but

small dealers, mostly those buying from day trip inshore vessels' are

a potential problem.

There are few serious processing problems involved in handling

shucked meats purchased from fishermen. The recent offshore fishery

from Casco Bay to Kittery has some unique problems since shucking is

done by the wholesale dealer or by people under contract to the

dealer. The landings are large and shucking has occupied available

labor and space in York and Cumberland County coastal towns. Disposal

of shells and scallop viscera has become a major problem and conflicts

over both legal and illegal dumping have arisen.

Landings have been characterized by an unusually high proportion

of sublegal scallops on occasion since harvesting and landing has been

conducted with little or no culling. Some attempts to utilize shucking

machines have been attempted but these machines operate efficiently only

when handling scallops of uniform size. Most of the bulk landings in

this fishery have been mixtures of different sized scallops and culling

and sorting is necessary before machine processing.

A large proportion of.the landings of scallops are distributed

347

through direct sales from harvester to consumer or retailer (restaurants

and local markets). This practice is almost universal east of Penobscot

Bay and in some other areas. Most of the scallopers in the eastern

Casco Bay area sell directly to consumers or restaurants (DMR Warden

Charles Hutchings, personal communication). These landings are unrecorded

and comprise a significant proportion of the Maine scallop harvest. Dow

(1979) estimated that reported landings in the 1967-72 period

represented only 59% of the actual inshore catch.

The processing sector of the scallop industry is conducted

primarily by the wholesalers and, aside from packing and shipping, there

are no elaborate procedures involved. The wholesaler usually buys from

fisherrien and other wholesalers and sells the scallops directly to

retailers or out of state wholesalers. The marketing structure of the

scallop industry is not clearly defined and direct sales to the consumer

may occur at any level from harvester to retailer.

There are few legal constraints imposed upon the processing sector

and, aside from license fees, there are no outstanding expenditures

involved in regulatory compliance. Intrastate distribution is covered

by the wholesale seafood license. Interstate shipments do not require

any licensing or inspection.

The proposed U.S.-Canadian fishery agreement for the Gulf of

Maine may affect scallop harvesting by Maine fishermen and the level of

imports sold through Maine shellfish dealers. The proposed allocation

348

(based on historical catches) of 75% of the total allowable catch (TAC) of

offshore scallops to Canadian fis hermen (Georges Bank area) is a current

subject of debate. The problem has been aggravated by the fact that U.S.

harvesting in recent years has risen to roughly 50% of the TAC on

Georges Bank. Georges Bank scallops comprised 23% of the Maine scallop

landings in 1979 (Table D-4-3). A negotiated reduction in the U.S. share of

this scallop harvest could adversely affect the Maine fishery and may

increase fishing effort on other offshore areas such as Cashes and

Jeffreys Ledges.

Economic Importance:

Scalloping has traditionally been a source of off-season income for

commercial fi shermen-in Maine. The expansion of harves ting to offshore

waters during the 1950's added a new dimension to the fishery; scalloping

remained an off-season fishery except that larger vesse ls, seasonally

engaged in ground fishing, were added to the scallop fishing fleet. The

economic importance of the scallop fishery is difficult to assess in

terms of impacts on harvesters and processors. The fishery has never

employed large numbers of harvesters (Table D-4-4) and few of these fishermen

consider scalloping as a major source of income.

The distribution of income from the scallop fishery is probably

more important than the actual dollar value of the harvest. Fishermen

usually do the shucking, a labor intensive process, and therefore a

significant portion of the landed value of the scallop harvest is

349

TABLE D-4-4.

MAINE SCALLOP LICENSES

YEAR LICENSES YEAR LICENSES

1948 272 1964 76

1949 290 1965 103

1950 295 1966 96

1951 226 1967 98

1952 120 1968 231

1953 116 1969 196

1954 90 1970 232

1955 103 1971 298

1956 100 1972 495

1957 83 1973 586

1958 62 1974 537

1959 59 1975 572

1960 67 1976 604

1961 59 1977 440

1962 68 1978 417

1963 61 1979 615

350

distributed as wages in the harvesting sector. Income from scallop

harvesting (inshore fishery) is primarily distributed in coastal

communiti es from Rockland to Eastport, an area of the state usually

characterized as "economically depressed" and therefore this income

has significant social impact. The number of scallop licenses

reported in Table D-4-4 do riot represent participation in the fishery

since deck hands are not licensed. Participation in the inshore

scallop fishery may be estimated at approximately 2.5 individuals per

license issued and therefore the scallop harvesting sector in 1979 may

have provided someincome for roughly 1500 people.

The distribution of income from the offshore fishery is probably

concentrated in the coastal area from Rockland to Kittery (major ports)

and involves a small number of large vessels with larger crews and

greater efficiency in terms of harvest and landed value per fisherman.

The economic parameters associated with the offshore scallop fishery

cannot be adequately defined with available data.

There are no adequate estimates of the number of processors,

wholesalers and retailers involved in the scallop industry. Anecdotal

information suggests that scallop handling does not constitute a major

portion of the business transactions of any fish or shellfish dealer

and, at this time, no valid economic assessments of the processing

sector can be made.

Product values, other than the reported landed values, are not

351

known. Current landed values for scallops (1980) ranges from $4.20 to

$4.50 per pound of shucked meats. The total landed value for the Maine

fishery in 1979 was approximately $3,878,413 (at an average price of

$3.33 per pound of shucked meats). The 1979 value per pound of scallop

meats closely approximates that of softshell clam meats. This close

correspondence indicates that economic values for Maine scallop

production could be approximated through the use of a shellfish value

multiplier (Wong, 1969). (See also: Appendix E-6 of this report).

Consumption of goods and services by the inshore scallop harvesting

sector can be approximated at 5/12 of the cost of operating a lobster

boat (based on vessel characteristics and the length of the inshore open

season). A comparable approximation for,the offshore fishery could be

derived from estimates of operating costs for medium sized draggers.

This has not been done because there are no data on the time spent in

scalloping by the average offshore vessel.

Evaluation of the Regulatory Framework:

Some regulations imposed upon the Maine scallop fishery have been

justified as being necessary or advisable because of biological

implications. The existing regulations, for the most part, do not have

any discernible biological justification or any demonstrable effect on

abundance or recruitment.

A minimum size limit could, theoretically, adjust the age at

recruitment and therefore optimize yield per recruit. The current

352

three inch minimum size limit does affect the age at first entry to the

fishery and has a tendency to increase yield. The yield estimates

computed by Serchuk et aZ. (1979) clearly indicate that a significant

increase in meat yield could be achieved by increasing the minimum size

of scallops to four inches (approximately --@35 meats per pound). From a

bioeconomic viewpoint an increase in the mean age at recruitment,

specified as a shell measurement or a stated number of meats per pound,

is.a most reasonable and prudent regulatory measure. This would increase

the mean age at recruitment by approximately one year.

There are some obvious problems with a statewide minimum size

limitation for scallops. In some areas, such as Penobscot Bay, scallops

apparently do not grow as rapidly as the norm nor do they reach a large

size. This., of course, indicates that a completely different set of

yield per recruit computations are needed for these slow growing stocks.

In these situations a four inch minimum length limit (and perhaps even

three inches) is.not reasonable and should not be imposed.

The value of any regulatory measure is tested by the standard of

enforcement. A restriction that cannot be enforced will invariably be

ignored. Enforcement of a minimum length limit for scallops is difficult

and expensive since it requires the examination of the catch during

fishing. It cannot be enforced at dockside because shells and viscera

are discarded at sea. This fact was clearly established in the recent

(1980) offshore fishery in the Gulf of Maine. Massachusetts attempted

353

to enforce a three-inch minimum length on shellstock landed by this

fishery; the fishery rapidly responded by shucking at sea and landing

only meats. In view of these problems minimum size restrictions should

probably be established on the basis of meats per pound, a restriction

that could be enforced at the point of landing.

Regulation of the minimum size of scallops through restrictions on

the size of dredge rings has been proposed as an alternative to minimum

size limits. Bourne (1965) compared the size frequency distributions

of scallops harvested by drags with three and four inch rings and found

that the larger ring conferred no selective advantage, i.e., that the

size frequency distributions of scallops taken by drags with different

ring sizes were similar. Selective escapement of small scallops.-ends

as soon as the drag is plugged with debris or larger scallops, usually

after a few minutes of towing. There is a slight disadvantage for

increased ring size; on rocky bottom the larger rings hang and break

more easily and gear maintenance costs are increased. This problem might

be resolved by using heavier gauge rings.

Management regulations, such as dredge size limitations and the

prohibition of some gear types are apparently selective measures which

evolved from competitive interactions within the harvesting sector.

These regulations have no apparent advantage in resource management and

may not even reduce fishing effort. The imposition of such regulations

should be avoided if possible since their only net ef f ect is to complicate

354

enforcement and obscure the evaluation of other management measures.

Competitive restrictions, e.g., those which discriminate against certain

types of gear, are appropriate only when economic management objectives

are necessary and when such objectives are clearly defined before.the

regulation is proposed.

The fortuitous coincidence of the scallop spawning period with the

inshore closed season on harvesting has been discussed in a previous

section. The net effect of the closed season, in terms of resource

management, is slight. The closure does impose.a seasonal interruption

in the systematic exploitation of some inshore scallop beds which may

provide some scallops with an opportunity to spawn. The magnitude of

this spawning and the net effect on abundance cannot be evaluated at this
time, The closed season does have economic and social benefits; it

prevents harvesting of scallops during the time that traditional

participants in the scallop fishery are more profitably employed in

lobstering. The season also effectively prevents gear conflicts between

scallop draggers and the lobster trap fishery. The closed season also

tends to reduce gear conflicts with the inshore gill net fishery which

is conducted during spring and fall.

Regulation of the scallop fishery outside the territorial waters of

the state is the responsibility of the federal government under the

provisions of the Fishery Conservation and Management Act of 1976

355

(Public Law No. 94-265). A scallop management plan is being prepared

under the FCMA which will address management of scallop resources of the

Gulf of Maine outside the territorial waters of the state. One of the

provisions of this plan will probably be a minimum size regulation of

30 meats per pound. This would restrict the taking of scallops less

than 5 years of age (those under four inches shell height).

Some Maine fishermen have challenged this minimum size with the

contention that Gulf of Maine scallops do not grow as rapidly as Georges

Bank and mid-Atlantic scallops. This argument for exemption may be

specious; slow growth has been reported for some populations inside the

state's territorial waters (e.g., Penobscot Bay) but there are

apparently inadequate data to support a slow growth hypothesis for

offshore scallops.

Resource Utilization:

Conflicts in resource utilization are almost a tradition in the Maine

scallop fishery and have generated some of the regulations imposed on the

fishery. Drag damage to lobster traps and gillnets appears to be an

occasional problem that has been rectified by negotiation or by adjustment

of the closed season. occasionally scallop draggers are prevented from

fishing desirable areas because of lobster traps and these conflicts have

usually been resolved in favor of the lobstermen.

Conflicts within the fishery are usually generated by competition

for specific harvesting areas and, in some cases, these have been resolved

356

through the regulatory framework (e.g., the Penobscot Bay otter trawl

prohibition, �6724). Conflicts between scallop draggers and SCUBA divers

have not been a significant problem because these types of harvesting

activity are usually not competing in the same fishing area. There have

been some competitive interactions between resident and nonresident

draggers in the recent southern Maine offshore fishery but most of these

conflicts have been resolved by traditional territorial agreements among

the fishermen. Most scallopers are involved in other fisheries for a

signficaint portion of the year and competition between full-time and

part-time fishermen has not been a problem.

Competing use of shore facilities for landings and gear storage

have not been a serious problem in most Maine ports. Most landings are

shucked meats and offloading is not a time consuming process. Scallop

drags and gear are relatively durable, compact and portable and gear

storage is not a problem.

Aquaculture of scallops has not been attempted in Maine although

it is, technically, feasible. Naidu and Scaplen (1979) have documented

aquacultural research for this species in Newfoundland and there appear

to be few major problems involved in culture. There has been an

adequate supply of high quality scallop meats produced in the Gulf of

Maine and this has probably restrained attempts at culture of this

species.

357

Baird, F.T.Jr. 1956. BIBLIOGRAPHY
The sea scallop (Pecten mageZZanicus). Maine Dept. Sea & Shore
Fisheries, Fisheries Education Series Unit No. 2.

Bourne, N. 1965.
A comparison of catches by 3- and 4-inch rings on offshore scallop
drags. J. Fish. Res. Bd. Canada, 22(2):313-333.

Caddy, J.F. 1968.
Underwater observations on scallop (Placopecten mageZZ-anicus)
behaviour and drag efficiency. J. Fish. Res. Bd. Canada, 25(10):
2123-2141.

Dickie, L.M. 1958.
Effects of high temperatures on survival of the giant scallop. J.
Fish. Res. Bd. Canada 15:1189-1211.

Dow, R.L. 1956.
The Maine sea scallop fishery. Maine Department of Sea & Shore
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1969.
Sea scallop fishery. In The Encyclopedia of Marine Resources, F.E.
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Effects of climatic cycles on the relative abundance and availability
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Periodicity of sea scallop abundance fluctuations in the northern
Gulf of Maine. Maine Department of Sea & Shore Fisheries, Research
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. 1979.
The inshore sea scallop fishery of the Maine coast. Maine Dept.
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Medcof, J,C. and N. Bourne, 1964,
Causes of mortality of the sea scallop (PZacopecten mageZZanicus).
Proceedings of the National Shellfish Assn., Vol. 53. pp. 33-50.

Merrill, A.S. and J.A. Posgay. 1964.
Estimating the natural mortality rate of the sea scallop (PZacopecten
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Naidu, K.S. and R. Scaplen. 1979.
Settlement and survival of giant scallop, Placopecten mageZZanicus,
larvae on enclosed polyethylene film collectors. In: Advances in
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Conference on Aquaculture, Kyoto, Japan.26 May-3 June, 1976.

National Marine Fisheries Service. 1979.
Market News Reports, B. series, Imports of Selected Fishery Products:
July through December.

Posgay, J.A. 1979.
Sea scallop PLacopecten magelLanicus (Gmelin). In. Grosslein, M.D.
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Serchuk, F.M., P.W. Wood, J.A. Posgay and B.E. Brown. 1979.
Assessment and status of sea scallop (PZacopecten mageZZanicus)
populations off the northeast coast of the United States.
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161-191.

Sutcliffe, W.H., K. Drinkwater and B.S. Muir. 1977.
Correlations of fish catch and environmental factors in the Gulf of
Maine. J. Fish. Res. Bd, Canada, 34(l):19-30.

Welch, W.R. 1950.
Growth and spawning characteristics of the sea scallop, PZacopecten
mageZZanicus (Gmelin), in Maine waters. M.A. Thesis, University of
Maine, Orono. 95 p.

Wilson, J. and R. Peters. 1978.
1978 census of New England commercial fishermen. Preliminary Draft
Report to the New England Fishery Management Council. June 22, 1978.

Wong, E.F.M. 1969.
A multiplier for computing the value of shellfish. U.S. Dept.
Interior, Federal Water Pollution Control Administration, Needham,
Ma.

359

ELEMENT D-5: A CHARACTERIZATION OF THE Cancer

CRAB FISHERY ALONG THE COAST OF MAINE

Joel Cowger and Jay S. Krouse

360

INTRODUCTION

The commercial crab fishery in Maine comprises the Jonah

crab (Cancer boreaZis) and rock crab (C. irroratus). These two

crab species, which are primarily harvested as an incidental catch

in the American lobster (Homams amer@lcanus) fishery, support a

small but increasingly important fishery which in 1979 had landings

of 1,344,179 pounds valued at $213,616 (ex-vessel price).

Since 1966, the price per pound of crabs paid to the fisherman

has increased from 4@ to 16@ (Figure D-5-1). Consequently, more Maine

lobstermen have been selling their incidental catches of crabs

(which might have been discarded in the past) to offset the upward

spiraling operational costs (bait, fuel, etc.). Considering the

increasing cammercial value of Cancer crabs, higher levels of fishing

effort are expected to be imposed on the crab fishery in future

years. In view of this, the application of biologically sound

management practices may be necessary to insure the protection and

enhancement of the crab resource.

361

DISTRIBUTION OF THE RESOURCE:

The rock crab is distributed in the coastal waters of eastern

North America from Labrador to Florida (Williams 1974). The depths

inhabited range from the intertidal area to about 575 m. In the

southern portion of their range, rock crabs are generally found

at greater depths where lower water temperatures prevail; however,

during the winter months when inshore waters cool, rock crabs

have been observed to move into these areas until temperatures rise

in spring-summer (Shotton 1973, Terretta 1973).

Jonah crabs are found from Nova Scotia to south of Tortugas,

Florida and in the Bermudas (Williams 1974). Like the rock crab,

the Jonah crab occurs near the low water mark in the more northern

latitudes and offshore in the south. Jonah crabs have been reported

in depths up to 800 m. of the two cancrid crabs, the Jonah crab

generally shows preference for greater depths. Observations of

several investigators (Jeffries 1966, Haefner 1976, Krouse 1980)

indicate that Jonah crabs undertake limited seasonal movements.

These movements are probably more dramatic in the crabs@ southerly

habitats.

Although both cancrid crabs occur along the entire coast of

Maine, the distribution and abundance of each species is related

to substrate type in association with depth and water temperature

(Yrcuse 1980)-. Rock crabs are extremely abundant at inshore areas

(-estuaries and embayments) characterized by soft sand-mud bottoms,

whereas Jonah crabs show preference for more seaward coastal areas

having hard bottoms of rock,.sand, and clay. This contrast in

362

habitat preference has been explained by Jeffries (1966) to be

due to morphological and behavioral differences between the two

species. The generally smaller rock crab, with its greater walking

ability, capability for burrowing, and quickness, is better adapted

for life on soft, featureless substrates than its heavy clawed

counterpart, the Jonah crab, which is relatively less active and

slower, and is dependent upon coarse substrates not only to attract

food organisms, but also to provide shelter from predators.

AVAILABILITY OF THE RESOURCE:

According to Fishery Statistics of the U.S., the first recorded

commercial catch of Cancer crabs (not separated by species) in Maine

was in 1919 when about 32.2 metric tons were landed (Figure D-5-1).

Interestingly, since the catch first peaked in 1930, rather pronounced

peaks have occurred about every 10 years thereafter, with the exception

of the 1950-60 period when the greatest catch (912.4 metric tons) in

the history of the fishery was made in 1963 (13 years after the last

peak). Sampling results indicate that more than 90% of the commercial

crab catch in Maine consists of rock crabs (Cowger 1978).

Fluctuations in the crab catch may be the result of many factors

such as overfishing, natural population cycles, and market demand.

Explanation of these catch variations is further confounded by the

inaccuracy of the landings values. In view of Cowger's (1978) estimate

that about half of the commercial crabmeat production in Maine results

from unreported "home-picking" operations, the reliability of the

landings data is seriously undermined. Nevertheless, this information

363'

still provides a relative index of catch size.

Cowger (1978) gives a detailed characterization of major

crab-producing areas. These areas are primarily located in the

mid-coastal region, where the large embayments provide suitable

habitat for rock crabs.

The Penobscot Bay-Deer Isle-Blue Hill Bay region is the most

productive area on the coast. Hancock County over the past thirty

years has produced about 45% of all Maine crab landings, and

virtually all of it has cane from the Penobscot Bay-Deer Isle-Blue

Hill Bay region.

Casco Bay is another productive area, and accounts for about

25% of Maine crab landings. The Sheepscot and Damariscotta Rivers

are both fished heavily for crabs. East of Blue Hill Bay there is

little crab fishing. The Jonesport area and the Machias Bay area

are the only areas in Washington County where crabs are caught in

any numbers,

variations in Availability:

The larval development of the Jonah and rock crab consists of

five zoeal stages and one megalops stage followed by the first crab

stage, at which time the crab f irst becomes a member of the benthic

community (Sastry and McCarthy 1973)-. During the larval period,

which.lasts 6-8 weeks, the young crabs are planktonic and, depending

largely upon ocean currents, may be distributed considerable distances

from where they were hatched. While young rock crabs (<40 mm carapace

width) seem to prefer rocky substrates, at least in their northern

364

distribution (scarratt and Lowe 1972, Krouse 1976), little is

known about the distribution of juvenile Jonah crabs. In fact,

the smallest Jo nah crab caught in Maine waters reported in the

literature was 67 mm carapace width (Krouse 1980).

As might be expected, larvae of both cancrid crabs require

certain temperature regimes for normal develoFment and optimum

survival (Sastry 1977). Significant deviation from these requirements

could certainly result in year class failures. Even though the two

species have rather similar environmental requirements, the variation

is sufficient to indicate the possibility of temporal succession in

larval development, thereby minimizing interspecific competition

within the pelagic environment (Sastry and McCarthy 1973).

Water temperature is not only an important factor during the

early life history of Cancer crabs, but also affects the distribution

of adult crabs. Along the mid-Atlantic coast the distribution and

abundance of Jonah and rock crabs have been clearly demonstrated to

be associated with temperature along with depth and substrate

(Shotton 1973, Terretta 1973, Haefner 1976, 1977). Moreover, in

the same region, population movements have been shown to be related

to seasonal variations in temperature. Similarly, along the Maine

coast, seasonal changes in sex ratios and relative abundance indices

of Cancer crabs indicate limited movements (Krouse 1972, 1980)..

Another important factor with regard to crab availability is

the fishing activity of man and the resultant fishing mortality.

Unfortunately, without catch and effort information it is difficult

to quantify this parameter and its effect on crab stocks. However,

based on comments of Maine commercial fishermen and limited crab

365

catch data (research traps) collected by the Maine Department of

Marine Resources, following the male rock crabs' molting period

in late winter-early spring (Krouse 1972) when many crabs are

recruited into the fishery (attain carapace width >95 mm)., the

abundance of harvestable-sized crabs diminishes drastically

throughout the summer (Cowger and Krouse 1978). Of course, part

of this reduction in the crab catch may be the result of emigration,

but it seems that most of the market-sized crabs are removed by the

fishery. Although this may explain, in part, the fluctuations in

rock crab abundance levels at many areas in Maine, the same may or

may not be true for Jonah crabs, which are the least understood of

the two crab species.

Cowger (.1978) found only one good crab-producing area on the

coast which was not fished fairly-'heavily. That area, upper Penobscot

Bay, is now supporting two full-time crab boats. It seems probable

that the crab resource in Maine is not capable of supporting

significantly increased fishing effort.

HARVESTING:

Most crabs harvested in Maine are taken by lobstermen as an

incidental catch,, although there is a small directed fishery on crabs

Most lobster traps are of wooden construction, but metal traps

(anodized aluminum or vinyl-clad steel) are becoming increasi.ngly

caLIlLon. variations in the basic design occur along the coast. All

traps, however, have features in common: side entrances (-"heads"),lead

366

to a bait chamber which in turn leads to a "parlor," from which

the lobsters are removed when the trap is hauled.

To save time in handling, many lobstermen have wide lath

spaces to allow undersize ("short") lobsters to escape. This

technique also allows crab escapement. Small crabs (including

most female rock crabs) will escape through the normal lath spaces.

In 1979 a trap vent law went into effect, which required that an

oblong escape vent at least 44.5 mm (1-3/4 in.) wide and 152.5 mm

(6 in.) long, or two circular escape vents at least 57.2 mm

(2-1/4 in.) in diameter, be incorporated into each lobster trap.

Fishermen who wish to retain market-size crabs often use the

circular vents.

In some areas of the coast, fishermen may set traps

exclusively for crabs, particularly during the.spring before

the lobsters cane inshore. These fishermen, still usually

interested in lobsters, have a number of lobster traps in use,

augmented by traps specifically designed to catch and hold crabs.

Although similar to a lobster trap in size and shape, the entrances

C"heads") are on top of a crab trap, rather than on the sides.

Crabs will crawl vertically over the the trap sides much more

readily than will a lobster, and by entering the trap through

the top, escape is virtually impossible, as neither the rock crab

nor the Jonah crab are swimming crabs. Lobsters are only rarely

found in crab traps; they may be hesitant to drop through the top

heads. Heads on Maine crab traps are usually constructed of Chlorox

367

bottles or equi valent which have had the top and bottan portions

removed, creating a smooth cylinder through which the crab drops.

The only other type of crab trap seen by the authors in use

in Maine is a trap designed for the blue crab (CaZZinectes sapidus)

fishery of the mid-Atlantic states. A crab fisherman in Cobscook

Bay, who has fished for rock crabs for 20 years, uses this type, a

metal trap which has low side entrances and a parlor above the bait

chamber to trap the blue crab, a swimming crab. He claims to have

tried the traditional top-head trapand found the blue crab trap

superior. He now fishes this trap exclusively.

Bait:

Lobstermen harvesting crabs as an incidental catch do not use

any particular bait to attract crabs - whatever is available for

lobster bait is what is used (generally ocean perch, herring, alewives,

flounder, or hake heads). Most fishermen agree, however, that crabs

prefer fresh bait. Marchant and Holmsen (.1975). found a similar feeling

among Rhode Island fishermen.

Those fishing crab traps have their own pet favorites for bait;

one,may prefer fresh mackerel, another may prefer dogfish, but they

all end up taking what they can get. If a small, live codfish is

taken in a lobster trap , it is often kept to be strung up in a crab

trap.

Crabs are attracted quickly to bait. Fishermen tending crab

traps in productive areas during peak season Clate spring, early

368

summer) often haul the traps twice per day, and each time the trap

may be filled. Rock crabs, in particular, also leave a lobster trap

quickly after the bait is consumed. When lobstermen are unable to

tend their traps for several days, the crab catch is smaller than

when traps are tended daily. Crab trap harvest, on the other hand,

is relatively unaffected by frequency of hauling (until the bait is

consumed), as the crabs are unable to escape through the top heads.

HANDLING:

Many lobstermen and dealers refuse to handle crabs, for various

reasons. The probleems most commonly cited can be summarized as follows:

1) Low value - many lobstermen do not want to bother saving a

product which is only worth about 16@ per pound (cr about 5-8@ per

crab), when lobsters are worth from $1.25 to $3.50 per pound. Saving

crabs on the boat does require sane handling, and separate holding

facilities are required. These lobstermen would prefer to spend their

labor hauling an extra dozen traps for lobsters.

2), Difficulty in keeping crabs alive on boats - crabs are not

hardy creatures out of water, and care must be provided to ensure

that they are kept alive after being placed in the boat. Soft-shell

crabs, which are abundant in early spring, are particularly tender.

Simple steps can be taken to minimize desiccation and overheating.

Crab loss is not a major problem during the cooler months of spring,

but when warmer weather arrives, an occasional dousing of the crabs on

board will prevent crab loss. One dealer on Deer Isle, who found that

369

too many dead crabs were being brought in during the summers, has

rigged up a small circulating water system for crab storage in

lobster boats, and provides the system free to his crab fishermen.

3.) High mortality in dealers' storage crates - many lobster

dealers have found high crab mortality when crates are stored for

more than 2-3 days. Soft-shell crabs store poorly.

Most dealers try to minimize storage time. Many will cull the

crabs.when they arrive, and fill storage crates only halfway during

the summer months. Some will ship 90 lb. crates in the spring and

fall, and then drop back to 80 lb. crates during the summer.

4) Fluctuations in demand - several lobstermen and dealers

refuse to handle crabs because they have had bad experiences in the

past with poorly managed picking facilities buying their crabs only

sporadically. This situation is unlikely to happen at this time, as

picking facilities are searching hard for supplies, and are likely to

provide a firm.market.

The above problems tend to occur in the marginal crab producing

areas. In areas where crabs are abundant, it is to the advantage of

both the lobstermen and the dealers to save crabs And exert the small

ef fort required to keep them alive. This is done, and crab loss is

neglig ible.

THE CRABMEAT INDUSTRY:

Crabs are usually sold by the crate; each crate normally contains

about 90 pounds of crabs. A crate of crabs in 1979 sold for an average

of about $14-15 (16@/lb.)_. The fishermen usually sell their crabs to

370

wholesale dealers (the lobster dealers, in most cases), who in

turn cull the crabs and sell to the picking houses. Some fishermen

may sell directly to the picking houses.

Although a small number of crabs are sold fresh or frozen at

the retail level, the vast bulk of the crabs harvested in Maine are

picked out by hand and the meat sold wholesale and retail (usually

in 6, 7, or 8 ounce cartons). The crabimeat industry is a small but

important coastal industry in Maine, worth well over a million dollars

a year. There are about 40 licensed crabmeat picking facilities.

It is only possible to get a rough estimate of the economic

value of the crabmeat industry because there are an unknown number

of "home pickers" - usually lobstermen's wives or housewives who

pick out crabs in their homes, and who sell on the roadside or to

the local market. The authors estimate that unreported

home-picking may account for perhaps a third of the total crabmeat

production in Maine. Home-pickers are most prevalent in Hancock and

Washington Counties, where they have often made it difficult for the

larger, licensed operations with standard business overhead expenses

to compete. Sanitary regulations have never been enforced by the

State Department of Agriculture.

In general, the demand for Maine crahmeat is greater than the

supply, as indicated by the 25% jump in prices to the. fishermen from

1978 to 1979. Crabmeat is in particularly high demand during the

summer tourist season. Many people prefer crabmeat to lobster meat,

even though crabmeat costs about half as much as lobster meat.

Crabmeat is not generally considered to be a substitute for lobster

meat - it caters to a separate market.

371

The twelve largest picking operations on the Maine coast,

from Portland to Machias, together produced about 150,000 pounds

of crabmeat in 1977, from a total of about 1,250,000 pounds of crabs.

Total crabmeat production fran all sources for that year may have

been as much as double that figure, or 300,000 pounds. Recent

expansion of licensed picking facility capability since 1977 is an

indication that the percentage of production fram these facilities

is increasing, and may now account for perhaps two-thirds of total

crabmeat production.

The retail price of crabmeat varies from $6-$8 per pound.

Using both a conservative estimate of 150,000 total pounds of crabmeat

produced each year in Maine, and a high estimate of 300,000 pounds,

the total value of the product would be:

150,000 lbs. x $6/lb. = $900,000 (low estimate)

300,00.0 lbs. x $8/lb. = $2,400,000 (high estimate)

The number of people employed in the cratmeat-picking industry

fluctuates constantly. Turnover is high, and variations in supply

force daily changes in the work force. Therefore, only a rough estimate

of the work force can be made. The ccimmercial picking operations employ

pickers for the period from April into November. The twelve large

commercial picking operations employ approximately 100 workers (mostly

in the Portland and Mount Desert Island areas). With the addition of

other licensed facilities, there are probably 150 pickers. Most of

the smaller facilities do not pick full-time, however. Pickers are

usually paid by the pounds of meat produced, in the range of $1.00/$1.35/lb.,

and may pick out anywhere from 2-5 pounds of meat per hour, depending on

experience and on the meat yield of the crabs at the time.

372

Most Maine crabmeat is sold right along the coast, and

virtually the entire supply is sold within New England.

MANAGEMENT CONSIDERATIONS:

Crab landings have varied considerably from year to year,

probably a result of natural population cycles and overfishing in

many areas. Two factors tend to self-regulate the industry.: one is

that it is not economical to pick meat from crabs smaller than about

90 mm in size (carapace width), so there is an informal minimum size

regulation in the industry; the other factor which has helped protect

the population is the small size of sexually mature females; most

female rock crabs are under 90 mm. in size, and therefore have not been

harvested. This situation is now changing somewhat, as the high price

of traditional lobster bait (alewives, herring, redfish, etc.) has led

some lobstermen (particularly in the Casco Bay ar ea) to use mall crabs

as bait. Continued expansion of this practice may have serious

consequences for the crab fishery, and should be watched closely.

There has been recent interest in machine processing of crabs.

At present there are two prototype machines in operation which extract

cra.bmeat fram hand-picked shell waste. This poses no management problems.

However, machine processing of whole crabs could create serious problems,

since small and female crabs would likely be harvested in that case.

There are no conflicts withother fisheries.

low ow an,

1111111 fill] 111 11.1-

-16

1000- 15
LANDINGS
:14Z
900-
13 0
0 CL I
800- -12
L )
tu
ac
1'- 700
LLJ
10 t@n-

Ln bOO 9 LU
u

LLJ
500- U
7

400- -6

300-

200- -3
PRICE -2
10

8 9 3 5 7 2 5 5 5 5
IQ tn M
.4 OYEAR 0 0

Fig. 1. Maine Rock Crab (Cancer irrovatus and C. borealis) Landings.

374

LITERATURE CITED

Cowger, J. D.
1978. An analysis of the Maine crab industry. Maine Dept.
Mar. Resourc. Res. Ref. Doc. 78/7: 39 p.

Cowger, J.D. and J.S. Krouse
1978. Comparison or rock crab (Cancer irroratus) catches
with research gear in 1969 and 1978 in upper Casco Bay, Maine.
Maine Dept. Mar. Resour. Res. Ref. Doc. 78/5: 8 p.

Haefner, P.A., Jr.
1976. Distribution, reproduction, and molting of the rock
crab, Cancer irroratus say, 1917 in the mid-Atlantic Bight.
J. Nat. Hist. 10: 377-397.
1977. Aspects of the biology of the Jonah crab, Cancer boreaZis,
1859 in the mid-Atlantic Bight. J. Nat. Hist. 11:303-320.

Jeffries, H.P.
1966. Partitioning of the estuarine environment by two species
of Cancer. Ecology 47: 477-481.

Krouse, J.S.
1972. Sane life history aspects of the rock crab, Cancer
irroratus., in the Gulf of Maine. J. Fish. Res. Board Can.
29: 1479-1482.
1976. Size composition and growth of young rock crab, Cancer
irroratus., on a rocky beach in Maine. Fish. Bull., U.S. 74:
949-954.
1980. Distribution and catch composition of Jonah crab, Cancer
bcreaZis_, and rock crab, Cancer irroratus_, near Boothbay Harbor,
Maine. Fish. Bull., U.S. 77: 685-693.

Sastry, A.N. and J.F. McCarthy.
1973. Diversity in metabolic adaptation of pelagic larval stages
of two sympatric species of brachyuran crabs. Netherlands J. Sea.
Res. 7: 434-446.

Sastry, A.N.
1977. The larval development of the Jonah crab, Cancer boreaZis
Stimpson, 1859, under laboratory conditions (Decapoda Brachyura).
Crustaceana. 32: 290-303.
1977. The larval development of the rock crab, Cancer irroratus
1817, under laboratory conditions (Decapoda Brachyura).
Crustaceana 32: 155-168.

Scarratt, D.J. and R. Lowe.
1972. Biology of rock crab (Cancer irroratus) in Northumberland
Strait. J. Fish. Res. Board Can. 29: 161-166.

375

Shotton, L.R.
197.3. Biology of the rock crab, Cancer irroratus say, in
the coastal waters of Virginia. M.A. Thesis, Univ. Virginia,
Charlottesville, 72 p.

Terretta, R.T.
1973. Relative growth, reproduction and distribution of the
rock crab, Cancer irraratus, in Chesapeake Bay during the
winter. M.A. Thesis, Coll. William and Mary, Williamsburg,
Va., 104 p.

Williams, A.B.
1974. marine flora and fauna of the northeastern United
States Crustacea: Decapoda. NOAA. Tech. Rep. NMFS Circ
389. 50 p.

376 4
I
'I
I
I

I
11
ELEMENT D-6: A CHARACTERIZATION
OF THE MAINE MUSSEL I
I
FISHERY I
'i
I
by
J. W. Hurst, Jr. I
i
I
11
'I
I

377

Mussels can be found along the entire Maine coast. Commercial

harvesting of mussels occurs from Casco Bay to the Machias River.

South of Casco Bay mussels are primarily limited to rocky shores with

relatively few commercially harvestable beds of mussels. most of this

area (York, Cumberland counties) is closed for fecal pollutio n. Few

mussels occur, at least intertidally, between Eastport and the Machias

River.

Efforts to establish a commercial fishery for blue mussels

commenced many years ago. Biennial reports of the Department of Sea

and Shore Fisheries (now the Department of Marine Resouces) indicated

that Department personnel and members of the fishing industry were

aware of the extensive mussel beds along the Maine coast early in the

1900's. The possibilities of establishing a market for mussels were

discussed in these reports'but no systematic harvesting or marketing

attempts were made.

In 1918, Irving A. Field of the U.S. Fish Commission (now the

National Marine Fisheries Service) made a survey of mussels along the

Maine coast from Portland to Eastport and estimated a total of 127,000

bushels of marketable mussels in the 52 localities surveyed (Field, 1922).

The stimulus for this survey was the interest of the fishing industry

during World War I in obtaining an additional source of protein foods

for canning. This canned product did not prove satisfactory with the

canning methods available at that time and the project was discontinued.

378

In 1942 and 1943, Leslie Scattergood and Clyde Taylor of the Fish and

Wildlife Service Onow the National Marine Fisheries Service) surveyed

mussel beds in central and eastern coastal Maine (Scattergood and Taylor,

1949 a,b,c). In the areas that Scattergood and Taylor surveyed they

estimated that the total harvestable supply of mussels from Eastport to

eastern Penobscot Bay was approximately 320,000 bushels. This estimate,

as the previous estimate in 1918, did not include many productive areas.

In 1977, Maritec surveyed mussel stocks from the Damariscotta River

estuary to Jonesport (Maritec, 1979). They estimated a standing crop

of 544,000 bushels. This survey covered a large portion of the coast

but it did not include some of the current harvesting areas.

Mussel landings were veXy:high during the war years, reaching a

peak production of 2.6 million pounds (173,000 bu.) in 1944. Most of

these mussels were canned. The popularity of mussels was due to the

low cost of the product and because they were not rationed. Canning

continued on a limited basis until the mid 1950's. mussel landings

between 1947 and 1956 averaged approximately 200,000,lbs. (13,000 bu.)

per year. From 1957-1965, annual landings averaged 34,500 lbs. (2,000

bu.), a very low production. From 1966-1974, annual landings rose to

an average of 300,000 lbs. (20,000 bu.). Beginning in 1975 an increased

demand for mussels occurred: 1975 600,000 lbs. (40,000 bu.); 1976 -

1,200,000 lbs. (80,000 bu.); 1977 2,100,000 lbs. (180,000 bu.); 1978

3,000,000 lbs. (200,000 bu.); and 1979 - 3,000,000 lbs. (200,000 bu.).

379

There is no evidence that shortages of available mussels were

responsible for the historical variations in mussel landings;

apparently consumer demand has been the source of this variability.

Today's market is for fresh mussels, unlike the war years when the

mussels went into the canned market.

Maine mussel harvesting methods have evolved as the market demand

increased. One of the earliest harvesting techniques was used for

intertidal mussel beds and involved beaching a dory on the mussel bed

at ebb tide, filling it with mussels during low tide and then floating

it off on the flood tide. Harvesting was thus limited by the number

of low tides during daylight hours and the height of those tides. A

measure of independence from the tidal cycles was gained when

harvesters employed long handled rakes and,subsequently, tongs to

harvest subtidal mussels. As market demand increased the harvesting

and selling of larger quantities of mussels attracted more sophisticated

gear and small day trip vessels began dredging mussels. This was the

first significant advance in Maine's mussel harvesting technology and

it has induced some problems for the industry. Dredging has provided

an ample supply of mussels for the market but they. sell at a relatively

low price and quality control is negligible. Advances in mussel

production technology will probably occur in the aquacultural field

rather than in harvesting and culling technology.

In 1955, Maine, Massachusetts, Rhode Island, Connecticut, and New

380

York conducted a one year cooperative study on the handling of mussels.

This study was a part of a long-range program to establish shellfish

sanitary standards by species and by areas instead of the current

general regulations for shellfish. The blue mussel was selected for

this study for two reasons: (1) this species has caused problems

because of its susceptibility to high bacterial scores in receiving

states; and (2) it was believed that a greater market for mussels could

be developed if recommendations to insure a high quality product

could be implemented.

The cooperative study resulted in the following recommendations:

Harvesting: must be from an open shellfish area.

Cleansing: should be sufficient to remove all dirt..and mud, the

mussels should be thoroughly washed, culled and free of dead and broken

mussels. The mussels may only be washed with water of drinking water

quality or from an approved growing area.

Shipping: mussels should be shipped in suitable clean containers

but not in bags of burlap or similar materials.

Temperature of shipping: mussels shall be kept at all times under

500F and above 320F.

Shipping containers were discussed at length in the study report

since it was recommended in 1956 that burlap bags were unsuitable for

mussel shipments and should be banned. Burlap bags are still used and

continue to be a problem. Selection of mussel shipping containers is

381

still dependent upon availability and cost. At the present time there

is a decline in the use of burlap bags. This is not due to a concern

about mussel quality but rather the availability of used bags and the

high cost of new ones. Burlap bags are being replaced by plastic mesh

bags. Mussels continue to provide all of the sanitary problems found

in 1956 along with the added problems of paralytic shellfish poisoning

(PSP).

The washing and culling of mussels has evolved during the last

several years from hand culling to the use of a grader-washer (drum

cage). The grader-washer is mounted upon the harvest boat or on a float

in the growing area. The washer, properly used, produces well separated

mussels free of mud and debris. Mussels.smaller-than 2" in length are

discarded in the growing area in the case of the boat mounted washer,

and to a pile of debris and mussels when the float mounted washer is used.

The mortality of the discarded mussels may be quite high. We have very

little information about the survival of the mussels returned to the

growing area after the dredging and washing aboard the harvest boats.

Dredging of mussels has opened many additional areas to harvesting

and has resulted in an increase in mussel landings because of

harvesting efficiency. Although dredging reduces the temptation to

harvest polluted mussels, it complicates the PSP monitoring program.

High mussel landings have continued and the harvest boats continue to

search for new sources of mussels. This has expanded the harvest areas

382

and much larger areas must be tested for PSP. We have sufficient

information to properly sample for PSP in these new areas, but it will

be necessary to vastly expand our monitoring program to define

suitable harvest areas during increases in PSP levels.

Maritec (1978) implied that the increase in mussel landings has

been due to the marketing of a higher quality product. Unfortunately

the re are no real guidelines and product standards and there is little

incentive for the mussel industry to voluntarily impose such standards.

In mos t instances the current mussel market does not distinguish between

high and low quality mussels. This depresses the landed prices paid for

mussels. These low prices, in turn, work against meaningful attempts

to improve the quality of mussels. There is a real and growing

interest in a high quality product. This is particularly true of the

cultivated mussel, with a limited specialized attempt to market selected

wild mussels. Protecting the public from PSP and polluted mussels is

relatively simple in comparison to the development of a continuously

high quality product.

There is no doubt that Maine has a limited supply of mussels. This

has been documented by Scattergood and Taylor (1943), who estimated

that there was a usable supply of mussels at approximately 310,000 bu.

(4,650,000 lbs.) and by Maritec (1978) who estimated a standing crop at

544,000 bu. (8,160,000 lbs.), with approximately 200,000 bu. (3,000,000 lbs.)

of high quality. Maritec has estimated that Maine could sustain an

383

annual production of approximately 100,000 bu. (1,500,000 lbs.).

Landings in 1978 and 1979 of 200,000 bu. (3,000,000 lbs.) are far in

excess of this estimate. Mussels are currently being harvested from

areas not surveyed by Maritec bu the mussel resource is indeed

limited and declines in annual harvests due to scarcity should be

anticipated. The mussel industry does not recognize a shortage of

mussels. Although it has been speculated that the drop in landings of

mussels in the late 1940's was due to a shortage of mussels, it is

highly likely that a decline in demand was the real cause. This is

because these mussels were used in the canned trade that, with the

return of other foods the market, no longer existed. Mussels for the

fresh seafood market accounted for the increased landings in the mid..

1970's.

Mussels continue to be a fairly inexpensive food and with other

shellfish in short supply they apparently have taken part of this

market. Maine fishermen receive a low price for their mussels ($3.00/bu.)

and this means that quantity takes precedence over quality. This does

not imply that Maine is shipping only poor quality mussels, but the

market apparently does not pay for quality and does not expect it.

Maine harvested mussels are marketed in Boston and New York. A

portion of this market is, reportedly, for processed mussels, frozen on

the half shell. Processing does not occur in Maine and this suggests

that Maine processors should investigate the possibility of entering

384

the processed and packaged mussel market. Several Maine processors

have investigated expansion into the shucked mussel market but have not

found it to be a profitable venture. Currently,there are approximately

50 firms dealing in mussels, with only a handful doing most of the

business (see Table B-6, pp. 108-114). The mussel industry has shown

little or no interest in any conservation or management of the resource.

Mussel aquaculture shows a great potential for a high quality

product. Lutz, 1979, has discussed the perspective of mussel mariculture.

He states in his abstract that, "Mussel cultivation presents an effective

means of expanding the resource base, and the accelerated growth and

superior quality of cultured mussels makes this product an attractive

addition to the.industry. Experimental and pilot commercial mussel

culture systems have been successful in various areas of the United

States (including Maine) and continued expansion of mariculture

operations offers the potential for a dependable commercia@ supply of

high quality mussels. To enable production at a competitive cost,

labor-intensive processes should be mechanized. Considerable research

is required in order to obtain an adequate understanding of the manner

in which biological and physical parameters will affect production

efficiency of large-scale commercial operations."

While there remain many unresolved biological and production

problems in mussel aquaculture, the most serious problems to be

resolved are probably social. The conflicting uses of the growing

385

area waters such as boating, recreational and commercial fishing,

while not always real, are definite deterrents to developing the full

potential of shellfish aquaculture. These conflicts are currently

resolved through the public hearing process involved in the Department

of Marine Resources' aquaculture permit system.

386

TABLE D-6-1

MAINE MUSSEL LANDINGS 1942-1979

Year Poimds Bu. Value Cents per Pound Bu.

1942 114,000 7600 910.00 $.008 .12
1943 1,983,450 132230 91,142.90 .049 .74
1944 2,633,635 175576 65,086.33 .025 .38
1945 2,574,945 171663 60,940,37 .024 .36
1946 2,314,210 154281 61,254.00 .026 .41
1947 40,260 2684 859.00 .021 .32
1948 124,129 8275 13,365.00 .108 1.62
1949 386,321 25755 15,345.00 .040 .60
1950 325,155 21677 11,370.00 .035 .53
1951 477,120 31808 13,472.00 .028 .42
1952 287,570 19171 8,725.00 .030- .45
1953 51,368 3425 1,301.00 .025 .38
1954 81,243 5416 2,048.00 .025 .38
1955 104,559 6971 2,829.00 .037 .41
1956 121,730 8115 2,170.00 .018 .27
1957 38,760 ;2584 4,547.00 .117 1.76
1958 120,417 8028 9,093.00 .076 1.14
1959 24,120 1608 1,705,00 .071 1.07
1960 49,755 3318 2,989.00 .060 .90
1961 2,179 145 92.00 .042 .63
1962 7,250 483 750.00 .103 1.55
1963 20,505 1367 1,407.00 .069 1.04
1964 15,410 1027 1,024.00 .067 1.00
1965 31,725 2115 3,025.00 .095 1.43
1966 239,789 15986 20,364.00 .085 1.28
1967 370,703 24714 31,473.00 .085 1.28
1968 389,402 25960 30,978.00 .080 1.20
1969 352,830 23522 28,625.00 .081 1.22
1970 301,118 20075 64,431.00 .214 3.21
1971 150,208 10014 35,051.00 .233 3.50
1972 280,740 18716 70,826.00 .252 3.78
1973 439,489 29299 116,000.00 .264 3.96
1974 308,328 20555 82,626.00 .268 4.02
1975 612,346 40823 198,036.00 .323 4.85
1976 1,203,194 80213 344,424.00 .286 4.29
1977 2,112,718 140848 680,309.00 .322 4.83
1978 2,997,432 199829 719,383.00 .240 3.60
1979 3,000,472 200031 716,128.00 .239 3.58

387

BIBLIOGRAPHY

Dow, Robert L. and Dana E. Wallace. 1954. Blue Mussels (Mytizus
edulis) in Maine. Dept. of Sea and Shore Fisheries.

Field, Irving A. 1922. Biology and Economic Value of the Sea Mussel
(14ytiZus eduLis). Bulletin, U.S. Bureau of Fisheries, Vol. 38:127-259.

Lutz, Richard A. 1979. Bivalve Molluscan Mariculture: A Mjtizus
Perspective. Maine Sea Grant, Tech. Rept. 40.

Maritec. 1979. An Inventory of th'e Blue mussel (MytiZus eduZis)
Stocks from the Damariscotta, River Estuary to Jonesport, Maine.

Scattergoodi L.W. and C.C. Taylor. 1949a. The Mussel Resources of the
North Atlantic Region: Part I - The Survey to Discover the
Locations and Areas of the North Atlantic Mussel Producing Beds.
Fishery Leaflet: 364, U.S. Dept. of the Interior.

Scattergood, L.W. and C.C. Taylor. 1949b. The Mussel Resources of the
North Atlantic Region: Part II - Observations on the Biology and
Methods of Collecting and Processing the Mussel. Fishery Leaflet:
364, U.S. Dept. of the Interior.

Scattergood, L.W. and C.C. Taylor. 1949c. The Mussel Resources of the
North Atlantic Region: Part III - Development of the Fishery and
the Possible Need for Conservation Measures. Fishery Leaflet: 356,
U.S. Dept. of the Interior.

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