Workshop on Marine Mammal-Fisheries Interactions in the Northeastern Pacific University Towers, Seattle, Washington, 19-20 December 1977

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U.S. DEPARTMENT OF COMMERCE
National Technical Information Service

PB80-175144

WORKSHOP ON MARINE MAMMAL-FISHERIES INTERACTIONS
IN THE NORTHEASTERN PACIFIC

BRUCE R. MATE

OREGON STATE UNIVERSITY
NEWPORT, OREGON

MAY 1980

QL
713.2
.M39
1980

it C

Report No. MMC-78/09

WORKSHOP ON MARINE MAMMAL-FISHERIES INTERACTIONS
IN THE NORTHEASTERN PACIFIC

University Towers, Seattle, Washington 19-20 December 1977

Bruce R. Mate, Ph.D.
Oregon State University
Newport, Oregon 97365

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Published May 1980

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2 3. Recipient's Accassion No.
MMC-78/09 PB80-175144

5. Report Date
and Subtlv
Workshop on Marine Mammal-Fisheries Interactions May 1980
In the Northeastern Pacific. 6.

7. Author(s) 8. Performing Organization Report No.

Bruce R. Mate
9. Performing Organization Name and Address 10. project/Task/Work Unit No:

Oregon State University 11. Contract or Grant No.
School of Oceanography MM8ACOO3
Newport, Oregon 97365 13. Type of Report
Sponsoring Organization Name and Address
Marine Mammal Commission Final Report
1625 1 Street, N.W.
Washington, D.C. 20006

5. Supplementary Notes
The views and ideas expressed in this report are those of the author.
They are not necessarily shared by the Marine Mammal Commission, its staff, or
its Committee of Scientific Advisors on Marine Mammals.
Abstract
The workshop reviewed what is currently known of marine mammal/fisheries
conflicts in Alaska, British Columbia, California, Hawaii, and Oregon (except sea
otter and tuna/porpoise problems). Set gear types (such as longlines and gill nets)
are more troubled by marine mammals (principally harbor seals and Steller or
California sea lions) taking the catch and damaging gea and moving.types of gear
(such as trolled hooks or drag nets). There are increased conflicts with sport
fisheries due to redistribution since the MMPA of 1972. The participants
determined what data and methods were needed to make future management decisions
and recommended that research be initiated on the conflicts of the Columbia River
to develop these types of data.

17. Originator's Key Words

Marine Mammal/Fishery Conflicts, Seal, Sea Lion, Porpoise, Gillnet Fishery,
Longline Fishery, Troll Fishery, Drag Fishery, Fishing Gear Damage,
Competition, Optimum Sustainable Population, Maximum Net Productivity,
Harassment, Incidental Take, Carrying Capacity

18. Availability Statement

Availability Unlimited

of the Report: 20. U.S. Security Classif. of This page 21. No. of Pages 12. Price Unclassified Unclassified

This Form may be reproduced.

TABLE OF CONTENTS

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 1

BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . 2

SUMMARY OF AVAILABLE DATA . . . . . . . . . . . . . . . . . . 4

Marine Mammals and Fisheries being Affected . . . . . . 4
History and Present Status of Marine Mammal
Populations and Management . . . . . . . . . . . . . 4
Incidental Take of Marine Mammals . . . . . . . . . . . 8
Marine Mammal-Caused Gear Damage, Fish
Damage, and Fish Loss . . . . . . . . . . . . . . . . 9
The Permit System . . . . . . . . . . . . . . . . . . . 17

FINDINGS AND CONCLUSIONS . . . . . . . . . . . . . . . . . . 17

Needed Information and Policy Determinations . . . . . . 21
Need for Better Methods of Data Collection . . . . . . . 21

SUMMARY AND RECOMMENDATIONS . . . . . . . . . . . . . . . . . 22

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . 24

BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . 25

GLOSSARY OF SCIENTIFIC AND COMMON NAMES . . . . . . . . . . . 26

APPENDICES

I Agenda . . . . . . . . . . . . . . . . . . 28
II Participants . . . . . . . . . . . . . . . 31
III Background Papers . . . . . . . . . . . . . 34
IV Summary of Available Information . . . . . 36
on Marine Mammal-Fishery Interactions
in the Northeastern Pacific
V Consideration of Management . . . . . . . 43
Al ternati ves
VI Ecosystem Studies and Models . . . . . . . 45

INTRODUCTION

Marine mammals interact with sport and commercial fisheries in a
number of ways. They are taken incidentally in fisheries such as the
yellowfin tuna purse seine fishery, are responsible for gear damage and
loss or damage of caught fish in fisheries such as the North Pacific
salmon gill net fishery, and, in several areas, compete with fishermen
for the same fish resources. The Marine Mammal Protection Act of 1972
was enacted, in part, because of concern that certain species and stocks
of marine mammals were in danger of extinction or depletion as a consequence
of incidental mortality and injury associated with fisheries such as the
yellowfin tuna purse seine fishery.

Prior to passage of the Marine Mammal Protection Act, sport hunting,
bounty hunting, and various forms of harassment were used to control the
distribution and/or abundance of certain marine mammal populations to
eliminate or reduce competition for fish resources and gear damage, fish
damage, and fish loss caused by marine mammals. The Act imposed a
moratorium on such taking and, in recent years, there have been reports
that populations of harbor seals and other marine mammals are increasing
and that there has been a corresponding increase in the amount of gear
damage, fish damage, and fish loss caused by marine mammals.

In response to the reports that marine mammal-caused gear damage,
fish damage, and fish loss were increasing in some areas, the Marine
Mammal Commission (MMC) sponsored a workshop to better identify the
nature and magnitude of the problem and what could be done to resolve
it. Since most reports of increasing gear damage etc. were from Alaska,
Washington and Oregon, the workshop focused on identifying the nature
and magnitude of the problem in these states. Because of similar problems
in adjacent states or countries and the possible movement of the involved
marine mammals across state and national borders, conflicts between
fisheries and marine mammals in Hawaii, California, and British Columbia
also were considered. l/

The workshop was held in Seattle, Washington on 19 and 20 December
1977 (Appendix I is the workshop agenda). Participants included representatives
of the Marine Mammal Commission, the National Marine Fisheries Service,
the fishing industry, the academic community, the Province of British
Columbia, and the States of Alaska, Washington, Oregon, California and
Hawaii (Appendix 11 is the list of participants). The workshop objectives
were to determine:

1. which species of marine mammals interact with specific
fisheries in Alaska, British Columbia, Washington,
Oregon, California and Hawaii;

9 how much is known regarding each of the marine mammal-fishery
interactions (i.e., the extent of incidental take, gear
damage, fish damage, and fish loss);

I/ To sharpen the focus of the workshop, issues related to the "tuna-
porpoise" problem and the sea otter/shellfish issue in California,
which are well known, were not considered during the workshop.

3. the types of biological, ecological, and socio-economic
data that will be needed to make sound management
decisions regarding such interactions; and

4. the methods of data collection that should be employed
to obtain the quantity and quality of data needed to
make sound management decisions.

Background papers were prepared by a number of workshop participants and
were circulated prior to the workshop and/or provided to participants
during the workshop (Appendix III lists the background papers).

BACKGROUND

Prior to passage of the Marine Mammal Protection Act of 1972, most
aspects of marine mammal protection and conservation were the responsibilities
of coastal states and/or international authorities such as the International
Whaling Commission, the North Pacific Fur Seal Commission, and the
International Commission on North Atlantic Fisheries. Management by
some of these authorities, particularly the international authorities,
was not very effective and, in the late 1960's, there were expressions
of concern, by the American public and the Congress, that certain species
and populations of marine mammals were in danger of extinction or depletion
as a result of man's activities. (cf., H.R. Report No. 92-707 (1972),
H.R. Report No. 92-1488 (1972), and S. Rep. No. 92-863 (1972)).

The Act established a moratorium on the taking of marine mammals in
U.S. waters and the importation of marine mammals and marine mammal
products into the U.S. It defines "take" as harassing, hunting, capturing,
killing, or attempting to harass, hunt, capture, or kill any marine
mammal and provides a special exemption for the taking of marine mammals
by certain natives for subsistence, handicrafts, and clothing. It also
provides for waiver of the moratorium and return of management to the
states, and for issuing permits to take marine mammals incidental to
commercial fishing operations and for purposes of public display and
scientific research.

Under the Act, the Secretary of Commerce is responsible for cetaceans
and pinnipeds, other than walrus, while the Secretary of the Interior is
responsible for all other marine mammals (i.e., walrus, manatees,
dugongs, sea otters, and polar bears). The Secretaries of Commerce and
the Interior have delegated responsibilities to the National Marine
Fisheries Service and the U.S. Fish and Wildlife Service, respectively,
and are authorized, among other things, to support research relative to
the conservation and protection of marine'mammals and to make grants to
assist States in developing and implementing State programs for the

protection and management of marine mammals. The Act established the
Marine Mammal Commission to advise the Secretaries of Commerce and the
Interior, and other Federal officials, as to actions needed to meet the
intents and provisions of the Act.

The primary objective of the Marine Mammal Protection Act is to
maintain the health and stability of the marine ecosystem and, whenever
consistent with this primary objective, to obtain and maintain optimum
sustainable populations of marine mammals. The Act defines "optimum
sustainable population" ("OSP") as "the number of animals which will
result in the maximum productivity of the population or the species,
keeping in mind the optimum carrying capacity of the habitat and the
health of the ecosystem of which they form a constituent element."
"Optimum carrying capacity" is defined as "the ability of a given habitat
to support the optimum sustainable population of a species or population
stock in a healthy state without diminishing the ability of the habitat
to continue that function."

To facilitate application in the management context, the National
Marine Fisheries Service has interpreted the statutory definition of
"OSP" as follows:

"Optimum sustainable population is a population size which
falls within a range from the population level of a given
species or stock which is the largest supportable within
the ecosystem to the population level that results in maximum
net productivity. Maximum net productivity is the greatest
net annual increment in population numbers or biomass resulting
from additions to the population due to reproduction and/or
growth less losses due to natural mortality." (50 C.F.R.
216.3)

This "interpretive" definition of OSP has been used in the course of
decisions concerning the status of porpoise stocks impacted by the
yellowfin tuna purse seine fishery and the State of Alaska's application
for a waiver of the moratorium on taking marine mammals. (cf. Report of
the workshop on stock assessment of porpoises involved in the Eastern
Pacific yellowfin tuna fishery. La Jolla, California. July 27-31,
1976. SWFC Admin. Rpt. No. LJ-76-29.).

The "interpretive" definition of OSP and the aforementioned provisions
of the Act, as well as the information summarized below, were discussed
by the workshop participants and considered in the process of identifying
research and management needs.

SUMMARY OF AVAILABLE DATA

As noted above, a number of workshop participants prepared background
papers which were presented and discussed during the course of the
workshop. The information contained in these papers is summarized
below. 2/

Marine Mammals and Fisheries being Affected

Marine mammals that affect, and/or are affected by, sport and
commercial fisheries in Alaska, British Columbia, Washington, Oregon,
California and Hawaii include the harbor seal (Phoca vitulina), the
Steller sea lion (Eumetopias jubatus), the CaliT-ornia sea lion (Zalophus
californianus), th-e northern fur seal (Callorhinus ursinus), the gray
whale (Eschrichtius robustus), the humpback whale (Megaptera novaeangliae),
the beluga whaleTD-eTphinapterus leucas), the pilot whale (Globicephala
macrorhynchus), the-killer whale (Orcinus orca), the bottlenose dolphin
(Tursiops truncatus), the harbor porpoise T:Ehocoena phocoena), and the
Dall porpo_is`eP5`6ocoenoides dalli). The commercial fisheries being
affected by marine mammals include: salmon gill net and troll fisheries
in areas such as Bristol Bay (Alaska), the Copper River Delta (Alaska),
the Columbia River (Washington-Oregon), Willapa Bay and Gray Harbor
(Washington), and Monterey Bay (California); the Japanese salmon drift
net and sablefish fisheries in the Bering Sea; the North Pacific halibut
fishery; the Alaskan king crab fishery; the West Coast hake and herring
fisheries; the California squid and anchovy fisheries; and long-line,
hand-line, and troll fisheries for tuna, bottom fish, and other species
in Hawaii. The sport fisheries being affected include salmon and steelhead
fisheries, particularly on the Columbia River (Washington/Oregon) and the
Rogue, Umpqua, Siletz, and Alsea Rivers in Oregon.

History and Present Status of Marine Mammal Populations and Management

The history and present status of marine mammal populations and
management in the Pacific states and the Province of British Columbia
are as follows: 3/

2/ Because of time contraints, workshop discussions were focused
primarily on issues related to the incidental take of
marine mammals and marine mammal-caused gear damage, fish
damage, and fish loss. The need to consider the possible
biological and socio-economic effects of marine mammals
and fishermen competing for the same fish resources was
recognized and is discussed briefly in Appendix VI.

3/ The information summarized here has been extracted from
background papers and other data sources provided by the
workshop participants. The subject area is complex and is
not discussed completely.

1. Alaska (This summary is based upon information provided by
by J. Burns, L. Lowry and K. Pitcher.)

Alaska has the greatest variety and largest populations of
marine mammals in U.S. waters. Utilization of these species
occurred prior to European influence and continues today by
natives for subsistence. A seal control program was instituted
in 1927 to reduce pinniped populations believed to be preying
heavily upon salmon in river mouth areas such as the Copper
River Delta and Bristol Bay. During the period between 1951
and 1958, 30,000 harbor seals were taken from the Copper
River Delta (Lensink, 1958). A regulated harvest program was
initiated in 1958.

The Marine Mammal Protection Act ended the State's
harvest program and management authority. Immediately after
passage of the Act, the State requested a waiver of the
moratorium and return of management authority for nine
marine mammal species. After more than five years,
a waiver and return of management has been effected
for only one species (walrus, Odobenus rosmarus). A
decision on the remaining eight species is pending. 4/

Information compiled by the State and presented during
the "waiver" proceedings indicates that the marine mammal
populations, for which the State requested a waiver, are
within the "optimum range" defined by the National Marine
Fisheries Service (see page 3). 5/

4/ Since this workshop, the return of walrus management to the
State of Alaska has been challenged in a law suit concerning
the regulation of taking by Alaskan natives and the State
has returned management to the Fish and Wildlife Service
which has suspended the waiver. The waiver and return of
management of the other eight species has been conditionally
approved but will not be effective until the State's revised
laws and regulations are submitted and approved. Further action
to implement the waiver and return of management have been delayed
pending a decision by the court and resolution of associated issues.

5/ This information, as well as other information, concerning the
waiver proceedings can be requested from the Alaska Department
of Fish and Game, the National Marine Fisheries Service, and the
U.S. Fish and Wildlife Service.

2. British Columbia (This summary is based upon information
provided by M. Bigg.)

Since 1913, marine mammal management policies in British
Columbia have varied according to public opinion. From 1913
to the 1960's, salmon fisheries influenced marine mammal
management policies. As a result, marine mammals were harassed
or killed to minimize competition, gear damage, fish damage,
and fish loss. During the period from 1913 to 1978, a reported
58,000 Steller sea lions were killed in government hunts, commercial
harvests, and by fishermen (one major rookery was completely
eliminated by 1939). From 1914 to 1964, approximately 110,000
harbor seals were reported killed. Protection was afforded
sea lions, harbor seals, elephant seals, killer whales, and
sea otters in 1970. Under this policy, none of these animals
can be harvested or killed without a permit. Since 1970, no permits
for control programs have been issued.

In 1968, the Steller sea lion population was estimated
at 5,000 to 6,000 animals (down from 12,000 to 14,000 in
1913). The present population of harbor seals is on the
order of 30,000 to 40,000 individuals. The current estimate
of killer whales, off eastern and southern Vancouver Island,
is 220 (from 1964 to 1977, a total of 26 killer whales were
taken for public display). The status of these populations,
with respect to the "optimum range" defined by the National
Marine Fisheries Service, has not been determined.

3. Washington (This summary is based upon information
providjed by M. Johnson and S. Jeffries.)

As in Alaska and British Columbia, seal and sea lion
predation on gill-netted salmon led to the establishment of
a bounty program. From 1947 to 1960, 9,503 seals were killed
for the bounty. In 1960, the bounty was eliminated but the
seals remained classified as predators. In 1970, all marine
mammals in the state were placed on the "protected" list.

The number of harbor seals in the coastal waters of
the state is thought to be increasing. The most recent
surveys indicate that there are approximately 5,500
harbor seals in the state's coastal waters. The status
of the harbor seal population and other populations of
marine mammals in the state has not been determined with
respect to the "optimum range" defined by the National
Marine Fisheries Service.

In the future, the state may consider seeking a waiver
of the moratorium and the return of marine mammal management
as provided for by the Marine Mammal Protection Act.

4. Oregon (This summary is based upon information
provided by D. Snow.)

Five species of pinnipeds are found in Oregon, two
of which are transient. The harbor seal, Steller sea
lion, and California sea lion are seasonally abundant,
while the northern fur seal and northern elephant seal
are only found in Oregon occasionally. �/

Prior to passage of the Marine Mammal Protection Act,
the state controlled seal populations to minimize impacts
on sport and commercial fisheries. From 1925 to 1933,
bounties were claimed for approximately 3,300 harbor seals
and 3,900 sea lions. In 1935, a seal control program
was initiated in the Columbia River, providing a bounty
($5.00 to $25.00) for each seal killed. From 1935 to
1972, the Fish Commission of Oregon paid bounty claims
on 3,150 animals. The Fish Commission also hired a
seal hunter (1959 to 1970) to control animals in the
lower forty miles of the Columbia River. During this
period, 468 seals were killed and 487 reported as
possibly killed or wounded - the kill ranged from
26 to 54 seals per year.

Since the control program was stopped, more
seals have been reported in the Columbia River and other
rivers and estuaries. Coastal aerial surveys conducted in
June 1976 and June 1977 produced counts of over 2,300 harbor
seals, 1,500 Steller sea lions, a few California sea lions,
and a few sea otters. These counts, when compared with
counts of 8 to 10 years ago, suggest that harbor
seal numbers are increasing in several areas.
The status of the harbor seal and other marine mammal
populations in the state have not been determined
with respect to the "optimum range" defined by the
National Marine Fisheries Service.

Oregon, like Washington, may consider seeking
a waiver of the moratorium and return of marine mammal
management as provided for by the Marine Mammal Protection
Act.

6/ Cetaceans, as well as pinnipeds, occur in the state's
coastal waters, but cetaceans do not have a significant impact on
fisheries and, for this reason, were not included in the
data survey.

5. California (This summary is based upon information provided
by M. Odemar.)

Six species of pinnipeds (harbor seals, California and
Steller sea lions, Northern and Guadalupe fur seals, and
Northern elephant seals) and numerous species of
cetaceans occur in the coastal waters of California.
From about 1860 to 1870, thousands of seals and sea lions
were harvested for oil. In more recent years, the state
has controlled certain marine mammal populations to minimize
impacts on fisheries. Control programs were ended in
1946 but, until the MMPA was passed in 1972, fishermen
were allowed to take California and Steller sea lions,
northern fur seals, and harbor seals when they were
endangering their gear or catch. Elephants seals and
Guadalupe fur seals were fully protected before passage
of the Marine Mammal Protection Act.

In 1976, the state requested a waiver and return of
management authority for the sea otter. The request
subsequently was withdrawn. The status of the marine mammal
populations in the state has not been determined with
respect to the "optimum range" defined by the National
Marine Fisheries Service.

6. Hawaii (No information on the history and status of
marine mammal populations and management in Hawaii
was presented at the workshop.)

Incidental Take of Marine Mammals

The number of marine mammals killed or injured during the course of
sport and commercial fishing operations in Alaska', British Columbia,
Washington, Oregon, California and Hawaii are not well documented. Gray
whales, humpback whales, pilot whales, and beluga whales occasionally
are entangled and drown in gill nets, trammel nets, and purse seines.
Smaller cetaceans, seals, and sea lions are more abundant and are entangled
and drown in nets more frequently. Dall porpoise, harbor porpoise,
Steller sea lions, harbor seals, and northern fur seals apparently are
taken in substantial numbers. It is estimated, for example, that
10,600 to 12,600 Dall porpoises and 3,150 to 3,750 northern fur seals
are taken incidentally each year in the Japanese salmon drift net
fishery in the North Pacific Ocean and the Bering Sea. 7/

7/ Since this workshop, the National Marine Fisheries Service has
convened a workshop on the "Dall porpoise problem" and the U.S.
and Japan have initiated a cooperative research program to assess
the nature and magnitude of the incidental kill and what can be done
to reduce it.

Marine Mammal-Caused Gear Damage, Fish Damage, and Fish Loss

Available information concerning the nature and extent of marine
mammal-caused gear damage, fish damage, and fish loss in the Pacific
states and the Province of British Columbia is as follows: 8/

1. Alaska

Steller sea lions, harbor seals, and beluga whales
apparently are the species responsible for most marine
mammal-caused gear damage, fish damage, and fish loss in
Alaskan waters. Steller sea lions primarily affect salmon
gill net fisheries, long-line fisheries for halibut and
sablefish, and the "pot" fishery for king crab. Harbor seals
primarily affect the salmon gill net fisheries in river mouth
areas such as the Copper River Delta and Bristol Bay.
Beluga whales damage gill net gear but do not remove fish
from the nets - they feed seasonally on smelt and adult salmon
in areas such as Bristol Bay and have been excluded effectively
from these areas by recorded killer whale sounds (Fish and
Vania, 1971). The most acute problems seem to be associated
with: (a) the Copper River Delta salmon fishery; (b) the
North Pacific halibut fishery; (c) the Bering Sea sablefish
fishery; and (d) the Alaska king crab fishery.

a. The Copper River Salmon Fishery (C. Matkin)

Imler and Sarber (1947) surveyed individual vessels
on the Copper River fishing grounds. They inspected over
10,000 fish and concluded that seal depredation on gill-
netted fish would not exceed 2% of the total catch.
In 1977, Matkin (unpubl. data) interviewed 15 fishermen
and extrapolated estimates of fish damage and gear
damage to estimate impact on the entire Copper River
Delta Fishery. The extrapolated estimates indicate
that approximately 30,683 fish were damaged (8.3% of the
total catch of 369,571), that the lost fish were worth
approximately $230,000, and that marine mammals caused
approximately $72,000 of gear damage. For the 445 boats
in the fishery, this would average $517 per boat for damaged
fish, and $162 per boat for damaged gear. Considerable
variability between boats was noted, some of which may
be attributable to the location of fishing operations.
It is not known whether the sample is reflective of the

8/ This subject area is very complex and relatively few quantitative
studies have been conducted. Much of the available information
is antidotal and has not been verified.

whole fleet and, therefore, whether the extrapolations
represent a realistic approximation of the amount of
gear damage and fish loss caused by marine mammals.

b. Halibut (B. Hardman)

The North Pacific Halibut Fishery was very large
until the mid-1960's when reduced stocks led to
reduced quotas and other regulations. At its annual
meeting in 1958, the International Pacific Halibut
Commission (IPHC) noted that Steller sea lions "at
least on certain fishing grounds in the North Pacific
interfere seriously with halibut taken on long-line
gear before they have been landed." Bell (1961)
estimated that approximately 8.1% of the caught fish
were either damaged or destroyed by sea lions resulting
in an annual loss to the halibut fishery of
approximately $500,000. There are no more recent
data, but since the fishery has been reduced in size
and no longer operates in many of the geographic areas
where severe fish loss was experienced in the past,
it seems likely that fish damaged or destroyed by
sea lions may be substantially less than in the past.
The problem continues to exist, however, and remains
a concern to the IPHC.

c. Sablefish (J. Burns)

Sablefish, also known as black cod, are caught by
foreign long-line fishermen and by domestic fishermen
using long-lines and fish traps. Japanese long-line
fishermen claim that Steller sea lions damage up to
50% of the catch in the Bering Sea south of the
Pribilofs. These claims have not been documented.

d. King Crab (J. Burns)

Pots for Alaskan king crab are deployed in
11strings" (serial units tied together by a strong
line) which rest on the bottom. Traditionally, the
line to recover the string of pots is held afloat
with two inflated floats. Steller sea lions apparently
bite these floats, causing them to sink, making
it difficult and time consuming, if not impossible,
for fishermen to recover the pots and the catch.
The fishermen have solved the problem by attaching
a solid styrofoam float (termed a "sea lion buoy")
to prevent the recovery line from falling
to the bottom in the event that the inflatable floats
are punctured. The extent of the problem and the cost
to the fishermen are not documented.

2. British Columbia (M. Bigg)

Marine mammal-fishery interactions in British Columbia
are similar to those in Alaska. The most acute problems are
with the salmon gill net and troll fisheries and are caused
primarily by Steller sea lions and harbor seals and, to
a lesser extent, by killer whales.

Schutz (1975) notes that killer whales may frighten
salmon (especially spring chinook), making them more
difficult to catch. Pike (unpubl. data) calculates that,
during the period from May to September 1962, Steller sea
lions caused an average loss of $54.00 in damaged fish
and $22.00 in damaged gear to each gill netter in Eastern
Hecate Strait. Fisher (1952) estimated that 8 to 12% of
the salmon catch was damaged by harbor seals. There apparently
are no more recent or comprehensive data.

3. Washington-Oregon

The harbor seal and California sea lion are responsible
for most marine mammal-caused gear damage, fish damage, and
fish loss in Washington and Oregon. The fisheries affected by
these marine mammals include the salmon gill net fishery and
the sport fisheries for salmon and steelhead. Although
not a problem at the present time, private- and state-owned
salmon hatcheries, which are becoming increasingly important
to augment reduced natural stocks of salmonids, could be
affected in the future. The most serious problem involves
harbor seals and the salmon gill net fishery on the
Columbia River.'

a. The Columbia River Salmon Fishery

Since 1972, fishery biologists from the Oregon
Department of Fish and Wildlife (ODF&W) annually have
examined 1-25% of the salmon caught in the Columbia
River and turned into processors. They found "predation
marks" presumably caused by seals, on 1-2.3% of the
fish examined (Hirose, unpubl. data). When extrapolated
to the fishery as a whole, these data indicate that
nearly 6,000 fish are damaged each year and that the
dollar value of these fish is approximately $60,000.

The highest rate of fish damage seems to occur
during "test" fishing (conducted prior to the commercial
season to help determine the size of the salmon run),
and late in the season during "scratch" fishing when
few fish are being caught and few boats are
fishing. The percentage of damaged and destroyed
(unusable) fish in the test fishery at River Mile 28
increased from 15% and 5%, respectively, in 1976 to
30% and 12%, respectively, in 1977. Damaged fish in
test fishing at River Mile 125 increased from 0% to
11% in the same time period.

Most of the fish damage and fish loss is
attributed to harbor seals (Pearson and Verts, 1970)
but fishermen also report that there were greater
numbers of California sea lions in the Columbia
River in 1977. Increased damage during "test" and
"scratch" fishing likely is due to the fact that
there are fewer boats fishing resulting in a higher
ratio of seals to boats.

b. Sport Fisheries for Salmon and Steelhead

The popularity of salmon and steelhead sport
fisheries on certain rivers in Oregon and Washington
apparently has declined in recent years. At the same
time, the numbers of harbor seals and sea lions apparently
have increased in these areas. Seals and sea lions
catch and eat salmon and there is a general feeling,
particularly among fishermen, that the seals and sea lions
are responsjble, at least in part, for the decline in
sport fisheries.

One example of the problem is the Rogue River
in southern Oregon where the local economy is based
largely upon tourism (which depends in part on
the River's world famous sport fishing reputation).
Oregon Department of Fish and Wildlife employees and
river guides claim that there have been increased
numbers of seals and sea lions in the river since
1973. Since then, the river has become less and less
popular for sport fishermen (which the local businessmen
attribute directly to the presence of seals and sea
lions), causing an unknown adverse economic impact on
the community.

Local residents have petitioned the National
Marine Fisheries Service to reduce or eliminate seals
and sea lions in the Rogue, Umpqua, Siletz, and Alsea
Rivers of Oregon.

c. Private- and State-Owned Salmon Hatcheries

Private- and state-owned salmon hatcheries are
becoming increasingly important for augmenting stocks
of salmonids which have been reduced due to over-
fishing, habitat deterioration, dams, and pollution.
State hatcheries are interested in adult salmon only
for their eggs and milt, and, to date, have shown little
concern over the presence of seals and sea lions in
areas where the adult fish are taken. Private groups,
which build and operate hatcheries to enhance harvestable
stocks of adult fish, may be more concerned about possible
seal and sea lion predation.

4. California

Marine mammals that affect sport and commercial
fisheries in California include the California sea lion,
the Steller sea lion, the harbor seal, the northern fur
seal, and the pilot whale. The fisheries that are
affected include: salmon troll fisheries in areas such as
Monterey Bay; the Indian gill net fishery for salmon
on the Klamath River in northern California; lampara
fisheries for squid and anchovy in southern California;
the beach and purse seine fisheries for herring; and the
mid-water troll fishery for hake. '

a. The Salmon Troll Fishery (B. Mate)

Some California and Steller sea lions apparently learn
to follow and take salmon caught by commercial trollers
and sport charter boats. Trollers drag from 2 to 12 lines
(some baited and some with lures) which are retrieved,
usually with a hydraulic assist, when a salmon
is caught. Sea lions sometimes follow boats for long
periods of time, taking the caught salmon before they
can be brought aboard. This type of "fish loss" occurs
in certain areas and may be caused by a small number of
animals that have learned to follow boats.

9-/ The salmon troll fishery occurs in the coastal waters of
the entire eastern North Pacific. Marine mammal-caused
fish damage and fish loss occur, to a greater or lesser
extent, throughout the fishery.

A study conducted in Monterey Bay, during the
1969 commercial salmon season, indicated that approximately
4% of the caught salmon were preyed upon by California
sea lions (Briggs and Davis, 1972). Sea lions also
were observed catching free-swimming salmon.

b. The Indian Gill Net Fishery in the Klamath River

There is an Indian gill net fishery in the Klamath
River in northern California which apparently has
experienced some difficulty with California sea lions.
It is reported (NMFS enforcement records) that, in the
spring of 1975, more than 50 sea lions were killed in the
river. Little more is known of the situation.

c. Squid and Anchovy Fisheries

Lampara nets are used to catch squid and live bait,
principally anchovy, in southern California. Squid are
caught in breeding areas, principally near
islands and rocky reefs, from November to January and
from March to May. Schools are attracted at night by
deck lights and then concentrated by use of small purse
seines, lampara nets, or half-ring nets (modified purse
seines with lampara-like wings). The squid then are
brailled from the partially drawn-up net. On larger
boats, the squid or anchovy are pumped out of the net
with a fish pump.

California sea lions and pilot whales apparently
are attracted by the dense concbntrations of squid or
fish in the nets, and tear large holes in them when
they become accidentally entangled or attempt to get
into or out of the nets. Holes in the nets permit the
catch to escape and must be repaired before fishing can
be resumed. The extent of the gear damage and fish
loss is unknown.

d. Herring and Hake Fisheries

Herring are taken in both beach and purse seines.
California sea lions, Steller sea lions, and harbor
seals eat herring and damage nets when they become
accidentally entangled or attempt to get into or out
of the nets. The extent of gear damage and fish loss
is unknown.

Hake is known to be an important component of
the diets of many marine mammals, including California
and Steller sea lions and northern fur seals, during
certain times of the year and in certain geographic
areas. Hake also is the target of a mid-water troll
fishery, primarily by foreign fishing vessels, and,
while the nature and extent of the problem are unknown,
it seems reasonable to assume that marine mammals are
taken incidentally or cause damage to this type of gear
or catch.

5. Hawaii

Porpoise are the primary cause of marine mammal-caused
gear damage, fish damage, and fish loss in Hawaii.
Fisheries affected by these marine mammals include long-line,
hand-line, and troll fisheries for tuna, bottom fish, and
other species.

a. Tuna (H. Yuen)

Long-lines consisting of between 120 to 600 hooks
on 8 to 38km of line are used to catch large species such
as tuna (Thunnus sp.), marlin (Makaira sp.) and shark
in the vicinity of the Hawaiian Islands. These lines
are fished at various depths, and are adjusted by buoys and
line length. Fishing is done during the day and, in some
areas, fresh mackeral scad, used for bait, apparently is
removed by porpoises (the rough-tooth dolphin, Steno
bredanensis, unverified) to the extent that fishermen
have had to abandon fishing. Fishermen in other areas
occasionally bring in their gear to find only the
heads of tuna and attribute these losses to
the false killer whale (Pseudorca crassidens). The
cost to the fishermen in terms of gear damage, fish
damage, and fish loss has not been determined.

b. Hand-Line Fisheries (H. Yuen)

A night hand-line fishery for big-eye tuna (Thunnus
obesus), albacore tuna (.1. alalunga), and yellowfin tuna
TT-.albacares) is conducted within two to twenty km offshore
off the southern half of the Island of Hawaii. Under-
water and surface lighting is used to attract squid (Notodarus
hawaiiensis) which is used for bait. Fishermen have reported
that tuna stop biting when porpoise are in the area.

A day hand-line fishery for yellowfin tuna takes place
off the southeastern and western shores of the Island of
Hawaii, where a single hook, baited with mackeral scad, is fished
at approximately 140 meters. Fishermen have reported porpoises

"hitting" the smaller tuna less than 15kg) off their
hooks and damaging larger tuna (40 to 50kg) by
"bumping" them on the ventral side. Although the
porpoise species has not been identified, one fishermen
in the South Point area says it is not the bottlenose
dolphin (Tursiops truncatus) and that only one or two
individuals out of a herd of 15 or 20 engage in the
practice of "bumping" hooked fish. At times the
catch will not be damaged although porpoise may be
within 10 meters. Attempts to lower protective
devices over caught fish proved unsuccessful.

A hand-line fishery for bottom fish, including
snappers (Pristipomoides microlepis, P. seiboldii,
Etelis carbunculus, Aphareus rutilans, A r . n
virescens), the carangid TS-erTo-la dumerl ii , and
the grouper (Epinephelus quernus), uses 6 hooks
spaced at 0.4 to 0.6m intervals at depths of
120 to 250m. Above the highest of these hooks
is a chum bag containing chopped fish which is opened
by a strong jerk of the line. The gear is fished
at 1 to 3m off the bottom from a 4 to 6m boat
and is pulled after several fish are hooked. In the
Kona area of Hawaii, bottlenose dolphins sometimes
remove the catch from the line while it is being
hauled. A single animal can remove six fish from
the line in the time it takes to get it to the surface.
When a porpoise jerks a fish from a hook, it may
pull 10 to 15m of line from the fisherman's hands,
thereby exposing him to the risk of open hooks.
This has been serious enough to cause fishermer+ to
quit using this method of fishing. Less than 30
Tursiops were thought to be involved when the problem
was most acute around 1975. Questioned in December
1977, fishermen indicated only 1 or 2 Tursiops
appeared on the fishing grounds.

The hand-line fishery for mackeral scad
(De.capterus Pinnulatus) takes place at night in
leeward areas over a bottom of 100-200m. Lights
placed underwater or at the surface are used in
conjunction with six feathered jigs attached to a
single lightweight line and fished at 15 to 25m
within the perimeters of the illumination. Off the
Kona coast of Hawaii and the Waianae coast of Oahu
porpoises sometimes take the catch from these jigs within
a few meters of the boat. Fishermen believe this
species is the bottlenose dolphin but are not certain.

The spinner dolphin (Stenella longirostris) and the
pigmy killer whale (F-eresa attenuta) have been
observed in the vicinity. Fishermen complain about
porpoises approximately one night out of four
(usually between 1400 and 2100 hrs.). Fishermen have
attempted to evade the porpoises by turning off their
lights and moving at top speed to another site
several kms away, without success. If their lights
are turned off and they drift, however, the porpoise
sometimes will move to another skiff in the vicinity.

The Permit System

Regulations promulgated by the National Marine Fisheries Service,
pursuant to Sections 101(a)(2), 104, and 103 of the Marine Mammal Protection
Act, provide for issuing permits which allow fishermen to take whatever
steps may be necessary to protect themselves, their gear, and their fish
catch from damage by marine mammals. Permits are issued in each of five
categories: (1) towed or drag nets; (2) encircling gear - purse seines
involved in deliberate setting on marine mammals and associated fish
schools; (3) encircling gear -purse seines that take marine mammals
accidentally; (4) stationary gear; and (5) other gear (e.g., troll and
long-line gear). Once a permit is issued for a given gear category,
fishermen may apply for certificates of inclusion. Certificates cost
fishermen $10.00 per year, except for class 2, which cost $200.00 per
year. Reporting of incidental take is required under the permit system.

Few fishermen have applied for permits or certificates of inclusion
in gear categories 1, 3, 4, or 5. 10/ In 1977, for example, only 115 of
the several thousand fishermen inv6_1ved in Pacific fisheries applied for
certificates of inclusion (see Table 1).

FINDINGS AND CONCLUSIONS

After reviewing and discussing the information summarized above,
workshop participants concluded: that substantial and, perhaps, significant ll/
numbers of marine mammals, particularly Dal] porpoise, harbor porpoise,
Steller sea lions, northern fur seals, and harbor seals are being killed,

10/ Gear category 2 applies to the yellowfin tuna
purse seine fishery, where fishermen "set-on-porpoise"
to catch the yellowfin tuna which associate with them.
U.S. fishermen involved in this fishery have certificates
of inclusion under the general permit issued to the
American Tunaboat Association.

Il/ For the purpose of this workshop, it was assumed that a few tens
of marine mammals constitute a "substantial" incidental take
and that any incidental take which results in a marine mammal
population being reduced and/or maintained below its level of
maximum net productivity, constitutes a "significant" incidental
take.

TABLE 1

Summary by region and by year of Certificates of Inclusion by
gear category, total investigations, reported incidental takes,
and NMFS notification methods.
NORTHWEST RrEGION

Gear
Category* 1975(1)* 197/6 1977 No. of---Investiqations
V
fl 5 0 0
3 14 0 2
4 9 0 1 7
5 146 14 17
Total 174 IT T-8
Appl. to
fishermen 10,000 ? ?

ALASKA REGION

Gear
Category* 1_975(2)** 1976(2)**1977(1)** No. of Investigations
;11 0 1
J 1
3 46 7
4 23 1 0
5 - 185 19
Total 48@ T5_4 _8
Appl. to
fishermen 18,000 18,000 News releases

SOUTH14EST REGION

Gear
Category*' 1975(2)** 1976 1977
1 1 1 0
3 28 4 40
4 1 0 1
5 39(+7FNW) 11 18(+VNIA)
Total 69 15 @_9
Appl. to
fishermen ? ? ?
No. Investiga-
tions 2 3 6
*1 = towed nets; 3 = purse seines outside the Eastern Tropical Pacific;
4 = stationary gear; and 5 = troll and longline gear.
means number of formally reported incidental takes.

i-njured, and harassed in conjunction with certain commercial fisheries,
particularly the Japanese salmon drift net fishery in the North Pacific
and the salmon gillnet fisheries in the Copper River Delta (Alaska) and
the Columbia River (Washington-Oregon); that certain species of marine
mammals, particularly harbor seals and sea lions, are causing substantial
and, perhaps, significant 121 economic damage to certain commercial
fisheries, particuarly the salmon gillnet fisheries in the Copper
River Delta and the Columbia River, and certain sport fisheries, particularly
salmon and steelhead sport fisheries in Oregon and Washington; that
remedial measures (e.g., gear regulations, enforcement actions, control
programs, etc.) may well be needed to permit the recovery or prevent the
depletion of one or more marine mammal populations and/or to maintain
the economic viability of one or more fisheries; and that available
information on the status of the affected marine mammal populations
and fisheries, and the nature and extent of the interactions among
them, is insufficient to determine the precise nature and extent of
remedial measures that may be needed, or justified, to reduce competition,
incidental take, gear damage, etc.

During the discussions, several workshop participants expressed
the view that marine mammals were being protected at the expense of
sport and commercial fisheries and that the Marine Mammal Protection Act
did not provide the flexibility needed to protect and conserve fisheries
and fish resources, as well as marine mammal populations. Other
workshop participants expressed the view that marine mammal protection
was being blamed, in some cases, for problems caused by poor fishery
management (e.g., over-capitalization of fisheries and over-harvesting
of fish resources) and that the Marine Mammal Protection Act does in fact
provide the flexibility needed to protect and conserve fisheries and
fish resources, as well as marine mammal populations. Relative to these
points, it was noted that:

while the MMPA provides for waiver of the moratorium on
taking marine mammals, and return of marine mammal
management to the States, only Alaska has requested a
waiver and return of management and, after more than 5
years and great expense on the part of both the State and
Federal governments, the waiver and return of management
has been effected for only one of the nine species for
which the State has requested a waiver and return of
management; 13/

12/ For the purposes of this workshop, it was assumed that a few
hundreds of dollars constitutes a "substantial" economic loss to
a fisherman and that any loss, which threatens the economic viability
of a fishery, constitutes a "significant" economic loss. It was
recognized that the economic viability of a fishery is dependent
upon a number of factors and that decisions concerning the
"significance" of marine mammal-caused gear damage, etc. would
be policy decisions and would require "value" judgments concerning
the possible cost and benefits to individuals, communities, states,
the nation, and the international community.

13/ See footnote 4.

while regulations promulgated by the National Marine
Fisheries Service provide for incidental take permits
which allow fishermen to take whatever steps may be
necessary - including killing and harassing marine
mammals - to protect themselves, their gear, or their
catch, few fishermen have applied for permits,
suggesting that: (a) marine mammal-caused gear damage,
fish damage, etc. is not a significant problem; or,
if it is, (b) many fishermen are "taking" marine
mammals illegally; and

given the intents and provisions of the MMPA, and
the NMFS' recent interpretative definition of
"OSP", the distribution and/or abundance of marine
mammal populations presumably can be controlled
if it is demonstrated that: (a) control is necessary
to maintain the health and stability of the marine
ecosystem; and/or (b) control is needed to maintain
the economic viability of a fishery and the proposed
"taking" will-be humane, non-wasteful, and will
not cause the affected marine mammal population
to be reduced below its level of maximum net
productivity.

Relative to the last point, it was noted that the level of maximum
net productivity of a population is determined, in part, by habitat
carrying capacity and that carrying capacity changes in response to
natural, as well as human-related factors (e.g., fishing and pollution)
and that determination of "optimum sustainable population" levels
would require determination of "optimum carrying capacities" as
well as levels of maximum net productivity. It also was noted that
habitat carrying capacity (optimum or otherwise) is difficult to
measure directly, that it most likely will be necessary to rely upon
indirect indicators rather than direct measurements to assess habitat
status and carrying capacity, that estimates of historic (pre-
exploitation) abundance often will be the only indicator of maximum
(pristine) carrying capacity, and that, given the NMFS' interpretative
definition of OSP, "optimum carrying capacity" likewise might be
interpreted as a range of carrying capacities bounded by the habitat
needed to sustain historic (pristine) population levels and the
habitat needed to sustain a population at its level of maximum
net productivity as determined with respect to maximum (pristine)
carrying capacity.

Needed Information and Policy Determinations

During the course of the discussions summarized above, it generally
was agreed that resolution of "marine mammal-fishery" conflicts would
require better information and/or policy determinations concerning: (a)
the status of the affected marine mammal populations with respect to
the "optimum range" defined in the NMFS's "interpretative" definition of
OSP; (b) the numbers, ages, sexes, and reproductive condition of marine
mammals taken during the course of sport and commercial fishery operations
and the effects of this incidental take on population status; (c) the
feeding habits, food preferences, and nutritional requirements of the
affected marine mammal populations; (d) the status of the affected fish
stocks with respect to optimum productivity or yield as defined in the
Fishery Conservation and Management Act; (e) the importance and status
of the affected fisheries with respect to capital investment, economic
viability, local economics, etc.; (f) the nature and e*xtent of marine
mammal-caused gear damage, fish damage, etc. and its effects on the
status of the affected fisheries; and (g) the structure, dynamics, and
status of marine ecosystems, and the effects of marine mammal-fishery
competition on the marine ecosystems of which the marine mammal populations,
fish stocks, and fishermen are component elements.

It was assumed that remedial measures may well be needed to reduce
incidental take and/or marine mammal-caused gear damage, etc. in certain
areas and, given this assumption, agreed that there is or likely will be
a need for information and determinations concerning (i) changes in
regulations, fishing gear, fishing practices, and/or enforcement activities
that might be required to reduce the incidental kill and injury of
marine mammals to insignificant levels; and (ii) the most appropriate
and humane methods for controlling the distribution, abundance, and/or
behavior of marine mammals so as to reduce marine mammal-caused gear
damage, etc. to insignificant levels.

Need for Better Methods of Data Collection

Most of the available quantitative information concerning the
numbers of marine mammals taken during the course of commercial fishing
operations and the extent of marine mammal-caused gear damage, fish
damage, etc. has been derived from personal interviews with fishermen,
mail surveys, or logbook surveys. Workshop participants noted that such
methods of data collection tend to provide biased data and concluded
that definition and resolution of marine mammal-fishery conflicts would
be dependent, in no small measure, upon developing better instruments
(e.g., questionnaires) and methods for collecting and verifying relevant
data. It was noted, for example, that:

questionnaires concerning the nature and extent
of marine mammal-caused gear damage, fish damage,
etc. will more likely be completed and returned by
fishermen experiencing such damage than by fishermen
not experiencing such damage;

tallies of damaged fish at processing plants tend to
underestimate economic losses since they do not
include fish which are completely removed from nets
by marine mammals or fish that are discarded by
fishermen because they are badly mutilated (e.g.,
fish heads);

fishermen generally are wary of government surveys,
believing that they often lead to additional
government regulations or enforcement efforts; and

many fishermen are fishing without certificates of
inclusion in general "incidental take" permits and,
understandably, are reluctant to report the incidental
take or injury of marine mammals.

It also was pointed out and noted that losses in sport fisheries are in
the "kind and quality" of recreational experiences which are and will be
difficult to measure directly.

During the course of discussions on needed methodology, it was
noted and agreed: that fishermen, government agencies, and private
interest groups must work together to identify and solve the problems;
that data collection has been and is being hampered because relatively
few fishermen have obtained certificates of inclusion in general "incidental
take" permits; that the reporting requirements, ten dollar filing fee,
and complex application procedure appear to be the primary reasons why
relatively few fishermen have obtained certificates of inclusion; that
the National Marine Fisheries Service should do everything possible,
including simplifying the application procedure and waiving the filing
fee, to encourage fishermen to obtain certificates of inclusion; that
one or more pilot studies should be undertaken to develop more reliable
survey instruments and procedures; that, whenever possible, surveys
should be carried out by academic institutions or consulting firms,
under contract to the responsible state or Federal agency,,to overcome
the credibility problems often encountered by government agencies in
conducting such surveys; and, finally, that appropriate test fishing and
observer programs should be developed and implemented to verify and/or
correct information obtained through surveys and "permit" reports.

SUMMARY AND RECOMMENDATIONS

In summary, workshop participants reviewed available information on
the nature and extent of marine mammal-fishery interactions in the
eastern Pacific and concluded that: (1) harbor seals, sea lions, and
other marine mammals apparently are impacting, and being impacted by,
certain commercial and sport fisheries; (2) there may well be some
validity to the reports that certain populations of harbor seals and
other marine mammals are increasing and that there has been a corresponding

increase in the amount of gear damage, fish damage, and fish loss
caused by marine mammals; (3) the most acute conflicts seem to be
between seals and sea lions and the salmon gillnet fisheries in the
Copper River Delta (Alaska) and the Columbia River (Washington-Oregon);
(4) while remedial measures may be necessary to reduce incidental take
and/or marine mammal-caused gear damage, etc. in certain areas, available
information is insufficient to judge the precise nature, extent, or
effects of the conflicts and what can or should be done to resolve them;
(5) research is needed to develop more reliable methods of data collection,
as well as to provide more reliable information on the nature, extent,
and possible effects of marine mammal-fishery conflicts; (6) research
also is needed to identify the most humane and non-wasteful methods for
controlling marine mammal distribution and/or abundance, should it be
determined that a control program or programs are necessary and appropriate
for reducing marine mammal-caused gear damage, fish damage, etc.; and
(7) data collection and ultimate solution of the problem are being
hampered by: (a) lack of a comprehensive, goal-oriented research program;
(b) funding limitations; (c) the apparent failure of many fishermen to
obtain "incidental take" permits and to report marine mammals taken
incidentally during fishing operations; and (d) the failure, on the part
of the Federal Government, to develop an effective and efficient permit
system and research program.

Based upon the aforementioned findings and conclusions, the workshop
participants recommended that:

1. the National Marine Fisheries Service do everything
possible, including simplifying the application procedure
and waiving the filing fee, to encourage fishermen to-
obtain certificates of inclusion in general "incidental
take" permits;

2. the Federal Government, in cooperation with appropriate
state agencies, undertake a comprehensive study of
marine mammal-fishery interactions in the Columbia
River (Washington-Oregon) and, if possible, the Copper
River Delta (Alaska) to develop appropriate methodology
and a model for assessing and resolving apparent marine
mammal-fishery conflicts in these, as well as other
areas; and

3. an additional workshop or workshops be convened to
identify research and/or management actions that appear
necessary or desirable to address questions concerning
the nature, extent, and possible effects of marine mammal-
fishery competition on (a) fish stocks, (b) marine mammal-
populations, (c) fisheries, and (d) the ecosystems of
which they are a part. (See Appendix VI).

In partial response to these recommendations, representatives of the
National Marine Fisheries Service indicated that the Service was investigating
and considering a number of possible alternatives relative to the "permit"
problem. Representatives of the Service also.indicated that, while
available funds were insufficient to initiate a comprehensive research
program, they expected some funds to be available for this purpose
beginning in Fiscal Year 1979. Representatives of the Marine Mammal
Commission indicated that the Commission would entertain a proposal to
bring together the responsible Oregon, Washington, and Federal agencies
and potential researchers from academic institutions to draft a coordinated
plan for marine mammal-fishery research in the Columbia River and adjacent
estuaries. 14/

ACKNOWLEDGMENTS

The Convenor thanks all of the participants for their pre-meeting
papers, presentations and constructive discussions. In addition,
considerable thanks go to Dr. G. Victor Morejohn (Moss Landing Marine
Lab.) for allowing the workshop to use his data from Monterey Bay; Dr.
Charles Woodhouse (Santa Barbara Museum) for incidental take and stranding
data; and Mr.-Robert Hudson (All-Coast Fishermen's Marketing Association)
for his remarks on the troll salmon fishery. Mrs. Grace Boden, Robin
Brown, Jim Harvey, and Tom Roffe provided logistic, clerical and technical
assistance which facilitated the meeting and final report preparation.

14/ The Commission subsequently received and funded such a proposal
and, in March 1978, scientists and representatives of the States
of Oregon and Washington met in Olympia, Washington, to begin
work on a research proposal to be submitted to the National Marine
Fisheries Service for funding consideration. Following the
workshop, the Commission also provided funds to develop methodology
and begin assessing the nature and extent of marine mammal-fishery
interactions in the Copper River Delta of Alaska (see pages 11 and
12 of the Commission's Annual Report for Calendar Year 1978).

BIBLIOGRAPHY

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Brooks, J.W. 1955. Beluga. In Annual Report for 1955. Alaska Dept. of
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Chapman, D.G. 1973. Management of international whaling and North Pacific
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Eberhardt, L. L. 1977. "Optimal" management policies for marine mammals.
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Fish, J.F. and J.S. Vania. 1971. Killer whales, Orcinus orca, sounds
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GLOSSARY OF SCIENTIFIC AND COMMON NAMES

Common Name Species
PINNIPEDS:
Steller sea lion Eumetopias jubatus
California sea lion Zalophus californianus
northern fur seal Callorhinus ursinus
spotted seal Phoca largha
ringed seal Phoca hispida.
ribbon seal Phoca fasciata
bearded seal Erignathus barbatus
harbor seal Phoca vitulina
northern elephant seal Flirounga angustirostris
walrus Odobenus rosmarus

CETACEANS:
gray whale Eschrichtius robustus
humpback whale Megaptera novaeangl iae
beluga whale Delphinapterus leucas
pilot whale Globicephala macrorhynchus
killer whale Orcinus orca
false killer whale P_seudorca crassidens
pigmy killer whale Feresa attenuata
Spotted porpoise Stenella attenuata
spinner dolphin Stenella longirostris
rough-toothed dolphin Steno bredanensis
bottlenose dolphin Tursiops truncatus
harbor porpoise Phocoena phocoena
Dall porpoise Phocoenoides dalli

MUSTELIDS:
sea otter Enhydra lutris

FISH:
anchovy Engraulis mordax
herring Clupea harengus
rainbow smelt Osmerus mordax
capelin Mallotus villosus
pollock Theragra chalcogramma,
steelhead Salmo gairdneri
chinook salmon Oncorhynchus tshawytscha
coho salmon Oncorhynchus kisutch
red salmon (sockeye) Oncorhynchus nerka
yellowfin tuna Thunnus albacares
skipjack tuna Euthynnus pelmis
kawakawa Euthynnus affinis
mackerel Decapterus pinnulatus
hake Merluccius productus

GLOSSARY OF SCIENTIFIC AND COMMON NAMES
(cont'd)
sablefish Anoplopoma fimbria
blue marlin Makaira nigricans
black marlin Makaira indica
striped marlin Tetrapturus audax
snappers Pristipomoides microlepis
P. seiboldii
Etelis carbunculus
Aphareus rutilans
Aprion virescens
carangid Serida dumerilii
grouper Epinephelus quernus
rockfish Sebastes spp.
halibut Hi2poglossus stenolepis

INVERTEBRATES:

squid Loligo opalescens
Notodarus hawaiiensis

king crab Paralithodes camtschatica

octopus Octopus spp.

APPENDIX I

REVISED AGENDA

for
Marine Mammal/Fishery Interactions Workshop
19-20 December 1977, University Towers, Seattle, WA

Tentative
Times 19 Dec.
0800 Charge to workshop participants - Doug Chapman (MMC)
SESSION I
An identification of marine mammal/fishery interactions in
each state including past, present-, and future management
policies - John Burns (ADF&G), Chairman
0820 Alaska : seals, sea lions, fur seals, beluga whales, others -
John Burns
0850 Washington: seals, sea lions, killer whales, others - Murray
Johnson (UPS-M)
0910 Oregon: seals, sea lions - Dale Snow (ODF&W)
0930 California: seals, sea lions, pilot whales, others -
Mel Odemar (CF&G); Gene Nitta (CA. NMFS)
0950 British Columbia: seals, sea lions, killer whales, others -
Michael Bigg (FRBC)
1010 Coffee

SESSION II
Discussion of specific data on marine mammal/fishery inter-
actions by fishery and gear type - Bruce Mate (OSU) Chairman
1040 gill netting - harbor seals: Cooper River - Craig Matkin (U.AK);
Ken Pitcher (ADF&G)
Gray's & Willapa Bays -
Murray Johnson (UPS-M)
Columbia River - Paul Hirose (ODF&W):
Kent Martin (CRFPU)
1140 beluga whales: Ken Pitcher (ADF&G)
1200 Dall porpoise & sea lions: high seas foreign fleets-
Bob French (NMFS/NWAFC)

1220 Lunch
1330 trolling - sea lions: Jim Harvey (Moss Ldg. Mar. Lab.)
1350 purse seining Jim Fraser (WDF); and/or Ken Pitcher
1410 private aquaculture/state hatcheries - Bruce Mate (OSU);
Dale Snow (ODF&W)
1450 sport fishery - Bruce Mate (OSU)

APPENDIX I
(cont'd)
Tentative
Times 19 Dec.

1510 Coffee
1530 Herring - Dale Snow (ODF&W)
1550 Halibut - Int'l. Pacific Halibut Comm. - William Hardman
1610 King crab (gear damage)
1630 Anchovy & mackerel (purse seine) - Bill Perrin (NMFS,SWC)
Squid lampara (Monterey) - Jim Harvey (Moss Ldg Mar. Lab.)
Hake Cliff Fiscus (MMD/NMFS)
Longline fisheries of Hawaii - Heeny Yuen (NMFS/Hawaii)
1700 Discussion of general feeding habits: Jim Harvey (Moss Ldg.);
L. Lowry & K. Pitcher (ADF&G);
Cliff Fiscus (MMD/NMFS)
1800 Bering Sea/pollock/fur seal model - Bruce McAlister (MMD/NMFS)
1820 Adjourn*
*According to progress, an evening session may be necessary.
20 Dec.

SESSION III
0800 Identification of data needed to make good management de-
cisions (considering also critical species and habitats, specific
fisheries, non.-biological disciplines, and geographic areas) -
Bob Hofman (MMC) Discussion Leader
0900 Methodology, data reliability & validation procedures -
0. Chapman, Chairman
Survey techniques - Lyle Calvin (OSU): Bruce Rettig (U.WA);
Donovan Thompson (U.WA); Courtland Smith (OSU); Lucy Sloan
(NFF)
1. 1. Enforcement: a. permit procedure - Pete Jensen(NMFS);
Al Stankowiak (NMFS/NW)
b. incidental take statistics
2. Surveys: a. fishermen; b. processors; c. other
3. Observers
4. Other

1000 Coffee
1020 Resume
1200 Lunch
1310 Resume

SESSION IV
1430 Identification of best research opportunities to obtain needed
management data (specific fisheries/gear types, population manipula-
tions, assessment of critical factors) - Bob Hofman (MMC) Chairman

APPENDIX I
(cont'd)
Tentative
Times 20 Dec.
1530 Coffee
1540 Resume
1600 Discussion of possible research funds & proposal preparation:
federal, state, university.
1640 Recommendations
1750 Adjourn

APPENDIX II

PARTICIPANTS

Michael A. Bigg Roger L. Gentry
Pacific Biological Station Marine Mammal Div.
Fisheries & Marine Service NMFS, MWFC
Dept. of Fisheries & Environment 7600 Sand Point Way, NE
P.O. Box 100 Seattle, WA 98115
Nanaimo, BC V9R5K6, CANADA
William Hardman
E. Reade Brown International Pacific Halibut Comm.
Game Management Div. P.O. Box 5009, University Station
Washington Dept. of Game Seattle, WA 98105
600 N. Capitol Way
Olympia, WA 98504 George Y. Harry, Jr.
Marine Mammal Div.
John R. Burns NMFS, NWFC
Marine Mammal Div. 7600 Sand Point Way, NE
Alaska Dept. of Fish & Game Seattle, WA 98115
1300 College Road
Fairbanks, AK 99701 James T. Harvey
OSU Marine Science Center
Lyle D. Calvin Newport, OR 97365
Dept. of Statistics
Oregon State University John P. Harville
Corvallis, OR 97331 Pacific Marine Fisheries Comm.
342 State Office Bldg.
Douglas G. Chapman 1400 SW 5th Ave.
College of Fisheries Portland, OR 97201
University of Washington
Seattle, WA 98195 Paul Hirose
ODF&W Clackamas Lab
Clifford H. Fiscus 349 W. Arlington
Marine Mammal Div. Gladstone, OR 97127
NMFS, NWFC
7600 Sand Point Way, NE Robert J. Hofman
Seattle, WA 98115 Scientific Program Director
Marine Mammal Commission
James Fraser 1625 Eye St., NW
Harvest Management Div. Washington, DC 20006
Washington Dept. of Fisheries
115 General Administration Bldg. Steven Jeffries
Olympia, WA 98504 Puget Sound Museum of Natural History
University of Puget Sound
Robert French Tacoma, WA 98416
Northwest & Alaska Fisheries Center
NMFS Peter Jensen
2725 Montlake Blvd., E. NMFS, Marine Mammal Permits
Seattle, WA 98112 Page Bldg., 3300 Whitehaven Drive
Washington, DC 20235

APPENDIX II
(cont'd)

Murray L. Johnson Gene Nitta
Puget Sound Museum of Natural History NMFS, SWFC
University of Puget Sound 300 S. Ferry St.
Tacoma, WA 98416 Terminal Island, CA 90731

Walter Kirkness Mel Odemar
Pribilof Islands Program (FNW6) State/Federal Fish Mgt. Program
NOAA, NMFS California Dept. of Fish & Game
1700 Westlake Ave., N 1416 Ninth St.
Seattle, WA 98109 Sacramento, CA 95814

Lloyd F. Lowry William F. Perrin
Div. of Game NMFS
Alaska Dept. of Fish & Game Fishery-Oceanography Center
1300 College Road 8604 La Jolla Shores Dr.
Fairbanks, AK 99701 La Jolla, CA 92037

Kent Martin Kenneth W. Pitcher
Box 80 Alaska Dept. of Fish & Game
Skamokawa, WA 98647 333 Raspberry Road
Bruce R. Mate Anchorage, AK 99502
OSU Marine Science Center R. Bruce Rettig
Newport, OR 97365 Institute for Marine Studies, HA-35
University of Washington
Craig Matkin Seattle, WA 98195
University of Alaska
Institute of Marine Science Lucy Sloan
Fairbanks, AK 99701 National Federation of Fishermen
38 Green St.
Bruce McAlister Cambridge, MA 02139
Marine Mammal Div.
NMFS, NWFC Courtland Smith
7600 Sand Point Way, NE Dept. of Anthropology
Seattle, WA 98115 Oregon State University
Corvallis, OR 97331
James Meehan
Fisheries Assessment Div., F-52 Dale Snow
NMFS Oregon Dept. of Fisheries & Wildlife
Washington, DC 20235 Newport, OR 97365

Terrell C. Newby Alfred L. Stankowiak
College of Fisheries Law Enforcement
University of Washington Marine Mammal Protection Div.
Seattle, WA 98195 U.S.D.C., NOAA, NMFS
1764 Federal Bldg.
915 - 2nd
Seattle, WA 98109

APPENDIX II
(cont'd)

Donovan Thompson
Dept. of Biostatistics
University of Washington
Seattle, WA 98195

Bent Thygesen
Portland Community College
12000 SW 49th Ave.
Portland, OR 97219

Lloyd A. Walker
Wildlife Management Div.
Washington Game Dept.
600 N. Capitol Way
Olympia, WA 98504

Heeny Yuen
NMFS
P.O. Box 3830
Honolulu, HI 98612

APPENDIX III

BACKGROUND PAPERS

Bigg, Michael. 1977. Conflicts between the salmon fishery and steller
sea lions, harbor seals and killer whales in British Columbia,
1913-1977.

Fiscus, Clifford H. 1977. A summary of information on the Pacific Hake,
Merluccius productus, the fishery, and marine mammals.

Fraser, Jim. 1977. Washington State marine mammal fisheries interaction.

French, Robert R. 1977. Estimated catch of porpoise and fur seal by the
Japanese salmon mothership fishery in the north Pacific Ocean.

Hardman, Bill. 1977. Predation on Pacific halibut by marine mammals.

Harvill e,John. 1977. Pacific Marine Fisheries Commission Resolution No.
9 and 10.

Hirose, Paul. 1977a. Incidence of seal-damaged salmonids sampled from
the lower Columbia river gill-net fishery, 1972-76.

Hirose, Paul. 1977b. Interactions between harbor seals and the gill-net
fishery in the lower Columbia River.

Hudson, Bob. 1977. Comments on conflicts with marine mammals in the
troll salmon industry.

Johnson, Murray and Steve Jeffries. 1977. Marine mammal-fisheries
interaction, Washington State, past and present.

Marine Mammal Division Staff (NFC). 1977. Impact of marine mammals on
salmon stocks.

Mate, Bruce R. 1977. Newly initiated studies to look at the impact of
harbor seals on aquacultural effort to enhance chum salmon resources.

Mate, Bruce R. 1977. The impact of seals and sea lions in freshwater
systems on sport fisheries.

Matkin, Craig 0. 1977. A preliminary evaluation of fishery depredations
by marine mammals on the Copper River Flats, Alaska, Spring, 1977.

Morejohn, G. V., J. T. Harvey and L. Krasnow. 1977. Marine vertebrates
feeding ecology in Monterey Bay, California.

Odemar, Mel. 1977. California Department of Fish and Game statement on
,rn.arine mammal management.

Perrin, W. F. 1977. Marine mammal/fishery interaction in the San Diego
area.

Pitcher, Kenneth W. 1977. General feedinq patterns of harbor seals and
Steller sea lions in the Gulf of Alaska.

Pitcher, Kenneth W. 1977. Belukha whales and salmon in Bristol Bay,
Alaska.

Snow, C. Dale. 1977. Oregon seals and sea lions.

Sullivan, Carl R. 1977. Optimum yield and the Fishery Conservation and
Management Act of 1976.

Woodhouse, Charles D. 1977. Marine mammal mortality near Santa Barbara.

Yuen, Heeny S. H. 1977. Marine mammal-fishery interactions in Hawaii.

APPENDIX IV

INFORMATION ON MARINE MAMMAL-FISHERY INTERACTIONS IN THE NORTHEASTERN P
SUMMARY OF AVAILABLE

Marine Mammal Location of Incidental mortality
Interaction Fish Loss or Damage Gear Damage of Marine Mammals

Eumetopias Alaska Japanese have estimat-
jubatus ed a 50% damage of N.R.* N.R.
sablefish caught in
Kodiak region & 2-30%
damage of catch in
Bering Sea south of
Pribilofs.

No. Pacific Log books from 58 ves-
(Cape St. sels of Pacific
Elias & Gulf Halibut fishery from
of Alaska) 1958/1960 indicate N.R. N.R.
8.1% of fish caught
were damaged or
destroyed. Extra-
polated to the whole
fleet, losses were
estimated at 500,000.

Hecate It was estimated that An estimated
.Strait, there was a $54 loss loss.of $22 N.R.
British per salmon gillnetter per gillnetter
Co I umb i a in damaged fish. These for damaged
losses were attributed gear was
to E.jubatus in May- reported.
Sept., 1962.

Oregon Salmon trollers have
reported loss of fish N.R. N.R.
from trolled hooks.

*N.R. - None reported at the meeting.

Marine Mammal Location of Incidental mortality
Interaction Fish Loss or Damage_ Gear Damage
of Marine Maimials Reference

Eumetopias Copper River Based on interviews of Gear.damage 40-50 in 1977
jUbatus delta, 15 salmon gillnet estimated at
(cont'd) Alaska.* fishermen an estimated an average of
8.3 of the fish were $162/boat
damaged (30,688/ ($72,000 for
369,571). This the fleet).
averaged out to a
loss of $517/boat in
damaged fish for the
445 boats in the fishery.

Coghill & N.R. N.R. 10 in 1977
Eshamy,
Alaska

Zalophus Monterey In 1969 4% of the N.R. N.R.
california n u s Bay, fish caught by
California salmon trollers were
dammaged. Observa-
tions were on only
0.21% of the catch.

California Damage to the catch N.R. N.R.
of the salmon troll
fishery has been
estimated as high as
$122,000 annually.
This represented 2.6%
of the ex-vessel landings.

Marine Mammal Location of Incidental mortalit
Interaction Fish Loss or Damage__Gear Damage of Marine Mammals

Zalophus California Take anchovy from purse Cause holes N.R.
Californianus seines and allow fish in nets.
(cont'd) to escape through
holes.

Oregon Movement of sea lions N.R. N.R.
up rivers & subse-
quent predation on
salmonids hooked on
sport gear.

Oregon N.R. N.R. Low numbers are
incidentally
taken in the
Pacific trawl
fisheries.

CallorhinuS North N.R. N.R. U.S. research
Urs i nus Pacific vessels estimate
Ocean & the Japanese high
Bering seas gill net
Sea fishery for salmon
incidentally catch
3,150-3,750 fur sea
Of the fur seals ta
in U.S. research
operations, 67% wer
alive & released. I
is not known what
proportion of the f
seals taken by the
Japanese are taken
alive and SUbsequen
released.

Harine Mamwal Location of Incidental mortality
Interaction fish Loss or DaiLi@_qq Gear Damage of Marine Majimials Reference
Phoca Copper Inspection of 10,000 Cause Imler & Sarber, 1947
-Vi-fu I i n a River caught fish in the dainage to
flats, salmon gill net fishery gill nets.
Alaska predicted that depreda-
(see also tion would not 40-50 killed Matkin**
E. jubatus exceed 2% of the total
catch.

Skenna During the 1940's a Cause N.R. Fisher, 1952
River, study of damage to damage to
Bri ti sh salmon caught in the gill,nets.
Columbia gill net fishery
revealed a loss of
7% for May-July. At
times the damage to
spring salmon rose to
12%.

Columbia Examination of salmon Cause N.R. Hirose ko
River delivered to the damage to
processing plant from gill nets.
1972-77 revealed that
1-2.3% of those
examined were damaged
(6,000 fish/yr or
approx. $60,000).
Annually 1.3-25%
ot' the total processed
were examined. Higher
percentage of spring
& sumiiier fish were seal
damaged.

Marine Mammal Location of Incidental mortality
Interaction Fish Loss or Damaqe Gear Daiuage of Marine Mammals Reference

Phoca Col umbi a While test fishing* Using diver nets, Ore. Dept. of Fish
vitulina River at river mile 28 the 4 harbor seals & Wildlife (Hirose,
-(@'6-n P-dy cont'd) incidence of were incidentally
"severely damaged" killed during 24
fish rose from 15% in sets in test
1976 to 30% in 1977. fishing.
Unsalable fish rose *Test fishing operations may encounter
from 5% in 1976 to greater f-ish damage because the test
12% in 1977. fishing bo@vt is the only boat fishing
Washington's test at the time.
fishing at river mile
125 changed from zero
damage in 1976 to 11%
of caught fish damaged,
in 1977.

Coghill & N.R. N.R. 15-20 incidental Matkin
Eshamy, Alaska to gill netting 4@1
C)

Oregon Reported up river N.R. N.R. Mate (Appendix 5)
systems where they
feed on sport hooked
salmonids.

gl obi cephal a California Anchovy escape On occasions, N.R. Gingerich (pers. comm.)
through holes pilot whales cited by Hate
!-hynchus made by marine become entrapped
mamma I s in anchovy purse
seine nets & tear
holes in the net
while escaping.

Orcinus British Fishermen feel N.R. N.R. Schutz, 1975
orca CO I Umb i a killer whales may
frighten salmon &
thus reduce the catch.

Marine Mammal Location of Incidental mortality
I n teracti on Fish Loss or Damage Gear Damage _of Marine Mammals

Delphinapterus Bristol N.R. Damage gill N.R.

leucas Bay, net gear.
Alaska

Steno Hawai i Longline fishery N.R. N.R.
for tuna, marlin &
shark have had
problems with
unverified Steno
taking bait off
hooks.

Tursiops Hawa i i Hand-line fishery N.R. N.R.
truncatus for snappers,
groupers & carangids-
fish removed from
hooks; I porpoise can
remove 6 fish. Also
line pulled thru
hands creates risk.

Phocoena- Copper N.R. Some damage 75 netted, at Matkin
phocoena River to gill nets least 30 killed
flats, during
Alaska entanglement.

Prince N.R. Same as 10 netted, Matkin
Wi I I iam above. (unknown number
Sound, Alaska killed)

Ceotral N. P. N. R. 12% of beachcast Morejohn (unpubl.data)
California animals examined
had probably
died as a result
of trammel net
entanglement

Marine Mammal Location of Incidental mortality
Interaction Fish Loss or Damage
Gear Damage of Marine Mammals

Phocoenoides North N.R. N.R. U.S. research F
dalli Pacific vessels give
Ocean & estimates of
Bering Sea 10,000-12,600
taken incidental
to Japanese high seas
gillnet fishery.

Copper N.R. Damage gill 5 netted (unknown M
River nets. number killed)
delta, Alaska

Prince N.R. N.R. 10 netted (un- William known number
Sound, killed)
Alaska

Pseudorca Hawaii Longline tuna N.R. N.R.
crassidens fishermen implicate
the false killer
whale in losses of
caught fish.

Eschrichtius California N.R. Damage tram- Some reported
robustus mel & grill for trammel net
nets in fishery
rockfish
fishery

These figures inclue impact of seals and sea lions - 75% of tile damage w
attributed to Steller sea lions, 25% to harbor seals.

Since tile workshop, these data have been published.

APPENDIX V

CONSIDERATION OF MANAGEMENT ALTERNATIVES

In weighing whether or not marine mammal populations should be
controlled as a management option, the ecological, subsistence, scientific,
economic, and esthetic values of the marine mammals (as individuals and
as a population) should be taken into account. "Economic value" pre-
supposes some commercial use (furs, pet food, etc.), but need not be
consumptive, i.e., some people pay money to see marine mammals "in the
wild" at land-based hauling areas or by boat charter. Many communities
place a high cultural and/or economic value on both marine mammals
and fisheries. The multi-million dollar display industry involving
marine mammals indicates the level of public interest. While
practical matters of economics or political expediency may favor
certain forms of management, the MMPA dictates that management options
address humaneness, waste, and alternatives to killing (such as
transplanting animals) in reducing population numbers. Some of the
alternatives which range from total preservation to total eradication
are listed below with comments.

1. Total preservation - possible adverse impacts to
fisheries, possible tourism benefits, possible
threat to fish populations if the human fishery is
unregulated.

2. Non-lethal harassment - could be short-term or in
limited areas to accomplish protection of fishing
gear, catch, entrance to a fish hatchery, or the
peak period of an anadromous fish run; continuous
harassment could affect mammals by disturbing
reproductive success (mating, birth, suckling),
reducing haul out periods of unknown importance,
possibly resulting in emigration and relocation of
population (depending upon the availability of
suitable alternative habitats).

3. Transplants - requires identification of biologically
and politically suitable habitat (the latter could
be the greatest problem unless the species is highly
"desirable"); agencies may wish to place limits to
growth (on the numbers or range) in areas of transplant
to minimize future problems; only a stop-gap measure
requiring continual transplant efforts if populations
being !'reduced" continue to expand, also requires finding
new suitable habitat as earlier transplant sites "fill",
with obvious financial commitment; cost per transplant
may be quite high.

4. Collection for scientific research or public display
can be limited to season and/or area; encourage collection
of live animals for authorized permit holders.

5. Hunting - can be limited to season and/or area

a) Professional hunter seasonal collection at period of
conflict may produce significant harassment and fulfill
goal of minimizing conflict without large kill
especially if done with associated cues (acoustic,
visual) which marine mammals may respond to without
reinforcement (killing).

b) subsistence hunting depending on species, cultural
acceptability, and safety of consumption; some safety
considerations, depending upon species and location.

c) sport hunting - seasons, bag limits, safety, enforcement
difficulties, development of regulations and quotas.

d) eradication - complete removal from geographic areas
within the range of a large stock may be technically
feasible, but would require considerable justification
and care to assure that the genetic stock is adequately
safeguarded (exchange, composition, etc.); could result
in unforeseen adverse changes in the ecosystem as a
result of food web disruption, especially at such
"high" trophic levels without complete understanding of
functional roles (as predator, prey and intermediate
host). See ecological considerations.

This list is by no means comprehensive, but identifies some of the
more obvious alternatives and suggests major considerations in evaluating
each. Any manipulative management will have to comply with the MMPA and
go through the waiver or permit process (assuring public scrutiny).

The waiver process will require an assessment of proposed management
programs relative to their possible impacts on marine mammal populations.
Follow-up studies to document the actual effects should be required.
There is so little known about most management alternatives that they
can and should be considered research programs. Research programs
require the same justifications as management programs where manipulation
(in the form of kill or harassment) takes place, but only need a research
permit and not a waiver of the Act or return of management authority to
a state. Adequate monitoring to evaluate various manipulative techniques
is essential to develop a predictive capability for future management
application and elimination of unacceptable practices.

In the event that management for whatever reason involves quotas
to be killed, incidental take may also be used as a guide to the
number of animals which can be removed (if population data were
collected concurrently and demonstrate no declines and if the
population can be shown to be at or above MNP levels).

APPENDIX VI

ECOSYSTEM STUDIES AND MODELS

Competition
Workshop participants expressed a general appreciation of the need
to understand natural feeding habits so that direct competition with
human fisheries could be put in perspective. It was generally agreed
that although many of the food web relationships were known on a qual-
itative level, much work needed to be done to develop quantitative in-
formation on the feeding habits of individual species of marine mammals
by region and season.

It was the objective of this workshop to deal with the direct take
of fishes from fishing gear and damage to that gear. However, partici-
pants recognized the value of and need to understand the trophic relation-
ships between marine mammals and other elements of the marine food web.
This would be a difficult and lengthy analysis by a group whose composi-
tion should include persons with specific expertise in many areas not
represented in this workshop. In view of the complexity of conducting
a full investigation of food webs, the workshop elected to review some
of the basic information which is being developed now for certain regions
in order to put the research needs for the fisheries competition in per-
spective with what is currently underway. Many of the studies underway
may also represent research opportunities for focusing investigations in-
volving fisheries conflicts.

I. Alaska

Several million dollars has been directed to research on Alaska mar-
ine mammals as a result of current and future offshore oil leasing. Most
of this money has come from the Bureau of Land Management's Outer Contin-
ental Shelf Energy Assessment Program (BLM/OCSEAP or BLM/OCS). Workshop
participants who are also principal investigators for some of these pro-
jects included the Alaska Department of Fish & Game (ADF&G), the University
of Alaska, and the Marine Mammal Division of NMFS.

The ADF&G is in the process of studying the trophic relationships of
four ice-inhabiting seals(the spotted seal, Phoca largha, the ringed seal,
P. hispida, the ribbon seal, P. fasciata, and the bearded seal, Erignathus
Ear-6-atus). From the basic re-search, two feeding patterns are emerging:
one is benthic and the other is much more diverse (but not primarily ben-
thic). Diets vary with geographic location and also seasonally. Feeding
habits vary with age and sex of animals (for example, long periods of
fasting among adult male otariids during the breeding season). Another
important feature is animal mobility. In essence, seals are "sampling"
a patchy environment in time and space. Availability of prey is not well
understood due to a lack of adequate resolution. Three or four prey ,
species usually account for 90% of seals' diets at any given location or
time, but many other species occur at much lower frequencies.

There is an apparent food size preference exhibited among these seals.
Ringed seals apparently prefer smaller food items (1 to 10 g), h-rbor and spotted
seals prefer food ranging in size from shrimp to larger scuipin (5 to 500 g)
whereas sea lions take the largest food items (10 g to several kg). Other
important considerations include depth, time, and range of foraging. Some
seals select specific food items on a seasonal basis, such as the bearded
seal, which feeds on the muscular siphon of pelecypods (clams) only at
certain times of the year. Selection of capelin (Mallotus villosus) over
pollock (Theragra chalcogramma) when both are in Bristol Bay by the spot-
ted seal (Phoca largha) demonstrates prey preference rather than simple
opportunism. Perhaps one of the most difficult parameters to assess is
the effect of learned feeding behavior. Examples cited included sea
otters opening beer cans to get resident octopus (Octopus spp.). Learning
may be an important aspect of marine mammals eating fish from fishing
gear.

Further studies by the ADF&G on Steller sea lions and harbor seals
collected from the western part of.the northeast Gulf of Alaska, indi-
cate that these species can be generally considered opportunistic
fish eaters, with fish comprising about 85% of their diet. Differential
consumption of cephalopouds, another major food,-is also shown. Squid are preferred
by sea lions, while seals prefer octopus. This may be prey preference or
reflect the relative abundance of these prey species in different forage
areas used by the two pinnipeds.

There are obvious data gaps in offshore feeding habits that need to
be filled in. Many (of what are considered to be) coastal species of
marine mammals may, in fact, be feeding offshore more often than is
realized. Changes in abundance and distribution of prey species of marine
mammals are important considerations. If, for example, an important food
item of a mammal should become steadily more abundant, this may increase
the carrying capacity of the environment for that mammal species. Con-
versely, significant reduction in prey density may cause a shift in feed-
ing habits or possibly a decrease in the capacity of a local environment
to support marine mammal populations.

II. The Bering Sea Pollock-Fur Seal Model
The Northwest and Alaska Fisheries Center of NMFS has, and continues
to develop, a Bering Sea model incorporating trophic interactions of the
pollock groundfish fishery and the northern fur seal populations showing
how they and eight other groupings of vertebrates and invertebrates in-
teract in the marine food web. The Bering Sea was focused upon because
of the accumulated knowledge of the pollock fishery in that area and food
consumption studies of fur seals (determined by stomach content analysis).
However, there is a lack of confidence in estimates used to construct the
model due to inadequate sample sizes or high variability, which prevents
this model from being a functional management tool. Some specific data
included in the model are as follows: estimated fish consumption by
fur seals - 500,000 metric tons per year (MT/yr), by birds - 500,000 MT/yr,
by other pinnipeds - 2,200,000 MT/yr, by whales - 400,000 MT/yr, and
totalling 3,200,000 MT/yr for all vertebrates. The estimated total

fishery catch is 1,400,000 MT/yr. 17% of the standing stock in the
Bering Sea is consumed per year and 2% is consumed by fur seals. In 10
years, changes in estimating techniques have raised the standing stocks
estimate of the Bering Sea from 7 million MT to 27 million MT. Squid
is the major non-vertebrate stock and is estimated at 4 million MT. Ap-
proximately 52% of squid stocks are consumed annually, largely by cetaceans,
an estimated 3% of the squid standing stock is annually consumed by
northern fur seals. This is perhaps the only attempt at the present time
to make quantitative estimates of the interactions of such a large and
highly complex food web. While the estimates lack confidence intervals,
modeling of this sort is useful in identifying what types of data influ-
ence the model most critically and hence subject it to greatest error.
Obvious areas of sensitivity include: 1) estimates of populations which
may be difficult to determine; 2) determining an average body weight for
a species; 3) the composition of feeding habits regionally and seasonally
for key species (e.g. little is known of the role of the feeding habits
of cetaceans); 4) small changes in food consumption rates (multiplied by
population, duration of predation, etc. make this a critical factor which
is poorly known and has been demonstrated to vary greatly for some species).
Food consumption rate estimates for northern fur seals vary from 5 to 21%
of body weight per day, probably due to variations of season, age and
sex of specimen, environmental conditions, and caloric content of prey
items.

The principal value of this type of model then becomes: 1) deter-
mining where incorrect values of various parameters occur; 2) identifica-
tion of data gaps where additional information is required; 3) identifica-
tion of elements of the model which are most sensitive to error. All of
these are important to know for the design of future research.

III. Central California
Work underway at the Moss Landing Marine Laboratory has been directed
toward a better understanding of Monterey Bay and the nearshore marine
food web. A baseline study investigating the vertebrate predation on the
commercial market squid was supported for three years (1975 to 1977).
Feeding habits of the marine fishes, birds, and mammals were examined in
Monterey Bay. Over 40 species of sea birds occur in Monterey Bay but
27 occur in large numbers and seasonally move into the bay for a three-
to six-month residence. Sixteen species consumed squid and eight fed on
squid extensively. Five species of pinnipeds and four species of ceta-
ceans were found beach cast and examined for feeding habits. Eighty-eight
species of fish were collected using hook,trawl, seine and gill net.

Fish predation in Monterey Bay centers on a few recurring prey items.
Squid, euphausiids, rockfish (Sebastes spp.), and anchovy were the signif-
icantly important food items for many species of fish. Birds, as well,
seem to feed more heavily on squid, anchovies and euphausiids than
on other prey. A division between specialists (Fulmar, Kittiwake,
Bonaparte's Gull and Rhinocerus Auklet) and generalists (Murre,
Shearwater, and Heermann's Gull) is evident from prey diversity. The
pinniped diet appears to favor fish while the cetacean diet favors squid.

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Although there is a general difference, both groups of marine mammals also
seem to prey most heavily on the recurring prey of birds and fish.

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DATE DUE

GAYLORD No. 2333 PRINTED IN U S A