[Federal Register Volume 59, Number 80 (Tuesday, April 26, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-9995]


[[Page Unknown]]

[Federal Register: April 26, 1994]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 227

[Docket No. 940408-4108; I.D. 031594A]

 

Endangered and Threatened Species; Coho Salmon in Scott and 
Waddell Creeks, CA

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of determination; status review.

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SUMMARY: NMFS has determined that the Scott and Waddell Creeks coho 
salmon populations in central California do not constitute a 
``species'' under the Endangered Species Act (ESA) and, therefore, do 
not qualify for listing under the ESA at this time. However, as part of 
a coast-wide status review NMFS is conducting of coho salmon 
populations in California, Idaho, Oregon and Washington, NMFS will 
determine if the two California populations are part of a larger 
evolutionarily significant unit that qualifies for protection under the 
ESA. A review of Oregon coho salmon stocks is expected to be completed 
in July 1994 and all stocks by October 1994.

ADDRESSES: Send requests for technical reports to Craig Wingert, NMFS, 
501 West Ocean Blvd., suite 4200, Long Beach, CA 90802-4213.

FOR FURTHER INFORMATION CONTACT: Margaret C. Lorenz, Office of 
Protected Resources, NMFS, 301/713-2322 or Craig Wingert, NMFS, 
Southwest Region, 310/980-4021.

SUPPLEMENTARY INFORMATION:

Background

    On March 11, 1993, NMFS received a petition from the Santa Cruz 
County Planning Department (petitioner) to add naturally spawning Scott 
and Waddell Creeks coho salmon (Oncorhynchus kisutch) to the list of 
threatened and endangered species and to designate critical habitat 
under the ESA. The petition contained information on electrofishing and 
trapping catch data to demonstrate declining population trends; 
provided information on geographic location, spawning distribution, and 
anadromous life history to illustrate evolutionary significance; and 
provided information on geographical isolation, distinctive life 
history and body size characteristics, and effects of hatchery fish to 
illustrate reproductive isolation. NMFS published a Federal Register 
document (58 FR 33605, June 18, 1993) indicating that the petition 
presented substantial scientific information that suggested listing 
might be warranted. To ensure a comprehensive review, NMFS solicited 
information and data concerning the present and historic status of the 
Scott and Waddell Creeks coho salmon, and whether this stock qualifies 
as a ``species'' under the ESA. NMFS also requested information on 
areas that may qualify as critical habitat for the Scott Creek and 
Waddell Creeks coho salmon. NMFS obtained information and data from 
several State, Federal, and local sources concerning the historic and 
present coho salmon abundance and distribution, water quality, fishery 
management practices, land management practices, hatchery management 
impacts, life history characteristics, and stock identification.

Biological Information

    The NMFS Southwest Region prepared a technical report entitled: 
``Status Review for Scott Creek and Waddell Creek Coho Salmon'', which 
provides more detailed information, discussion, and references. The 
report is available upon request (see ADDRESSES) and is summarized 
below.
    Scott Creek and Waddell Creek are neighboring watersheds that flow 
into the Pacific Ocean within 4 miles of one another. These two streams 
are located on the north coast of Santa Cruz County approximately 15 
miles to the north of the City of Santa Cruz, California. Scott Creek's 
main stem is 18 miles long, with 35 miles of tributary length, and a 
watershed that covers 35 square miles. Waddell Creek's main stem is 12 
miles long, with 45 miles of tributary length, and a watershed that 
covers 26 square miles.
    Coho salmon (Oncorhynchus kisutch) are anadromous along the Pacific 
coast from Chamalu Bay, Mexico, to Point Hope, Alaska, through the 
Aleutians, and from the Anadyr River, U.S.S.R., south to Hokkaido, 
Japan. In California, coho salmon historically used most of the 
accessible coastal streams from Monterey County north to the Oregon 
border.
    There are two basic life history spawning strategies for coho 
salmon: Short-run populations which utilize the smaller coastal 
streams, and long-run coho that will migrate up to 320 miles to utilize 
tributaries of large coastal rivers. Coho salmon may begin to enter 
freshwater in September but usually enter from October to March, 
peaking in December and January. In Scott and Waddell Creeks, spawning 
of coho salmon primarily takes place from the end of December through 
mid-February, usually coinciding with increased storm flows. After 
spending one year in freshwater, juvenile coho salmon migrate to sea 
where they usually spend two growing seasons before they return as 
adults to freshwater to spawn as 3-year-old fish. A relatively small 
portion of adult male coho salmon return to spawn after only one year 
at sea, and are termed jacks or grilses.

Consideration as a ``Species''

    To qualify for listing as a threatened or endangered species, the 
Scott and Waddell Creeks coho salmon populations would have to be a 
``species'' under the ESA. The ESA defines a ``species'' to include any 
``distinct population segment of any species of vertebrate * * * which 
interbreeds when mature.'' NMFS published a policy (November 20, 1991; 
56 FR 58612) on how it will apply the ESA species definition in 
evaluating Pacific salmon. This policy states that a salmon population 
will be considered distinct, and hence a species under the ESA, if it 
represents an evolutionarily significant unit (ESU) of the biological 
species.
    The population must satisfy two criteria to be considered an ESU:
    (1) It must be reproductively isolated from other conspecific 
population units; and
    (2) It must represent an important component in the evolutionary 
legacy of the biological species. The first criterion, reproductive 
isolation, need not be absolute, but must be strong enough to permit 
evolutionarily important differences to accrue in different population 
units.
    The second criterion is met if the population contributed 
substantially to the ecological/genetic diversity of the species as a 
whole. Further guidance on the application of this policy is contained 
in, ``Pacific salmon (Oncorhynchus spp.) and the Definition of Species 
under the Endangered Species Act,'' which is available upon request 
(see ADDRESSES).

Reproductive Isolation

    For this criterion, NMFS considered information provided by the 
petitioner, information provided by knowledgeable sources, scientific 
documents, and commercial reports concerning the isolation of Scott and 
Waddell Creeks from other coho salmon spawning streams, the distance of 
the Scott and Waddell Creek populations to other coho salmon 
populations, the time of peak spawning, and a north-south genetic 
difference.
     Available information does not make a strong case for reproductive 
isolation of Scott and Waddell Creeks coho salmon. Marked coho salmon 
from Scott and Waddell Creeks have been caught in the Noyo River 200 
miles to the north near Fort Bragg, CA, and in the San Lorenzo River 15 
miles to the south in the City of Santa Cruz, CA. Therefore, distance 
in the ocean is not a good measure of reproductive isolation from other 
coho salmon populations.
    The San Lorenzo River coho salmon population is primarily a 
hatchery maintained population that has been extensively stocked with 
coho salmon from numerous other northern watersheds for over 70 years. 
Although the loss of other coho salmon populations south of San 
Francisco Bay has isolated these populations, the distance of the Scott 
and Waddell Creeks populations to other north-coast coho salmon streams 
is well within their migration range based on their reported straying 
over the last 50 years.
    Many small coastal streams in California and Oregon are closed by 
sand bars at their mouths during a portion of the year. Generally, fish 
cannot enter the stream until the sand bar is broken, usually by the 
first heavy rains. Although the formation of a sand bar may temporarily 
act as a migration barrier, it does not represent a reproductive 
isolation mechanism.
    The timing of coho salmon spawning runs may be partly genetically 
based, but it is also subject to modification by streamflow, water 
temperature, and other environmental variables. Data from other river 
systems indicate that the timing of spawning migrations is generally 
attributed to an increase of stormflow runoff (usually occurring 
earlier in the northern range of coho salmon populations), which allows 
the salmon to migrate through the lagoons/estuaries and higher up the 
river systems to their natal tributaries.
    Since studies in the 1930's and 1940's, there has been an apparent 
shift in peak spawning migration timing by coho salmon in Scott and 
Waddell Creeks to several weeks later in the season. Spawning 
migrations in most California coastal streams and rivers have shifted 
to later in the spawning season, possibly due to degraded conditions 
within the watersheds, rivers, and estuaries. The loss of large woody 
debris within stream systems which helps flush out sediment and creates 
deep holding pools, excessive diversion of drought limited flows which 
increases water temperatures, and a reduction in area and volume of 
most estuaries and rivers due to filling with sediment, may have 
created conditions in which coho salmon can no longer access or survive 
in rivers until the start of heavy winter rains. Although other 
explanations are possible, the year-to-year variation in the timing of 
coho spawning migrations in Scott and Waddell Creeks are similar and 
within the range of run times reported for other coho salmon 
populations in California and Oregon. The modest difference in peak 
spawn timing cited by the petitioner may reflect (or may be the result 
of) reproductive isolation, but the best available data is inconclusive 
regarding the cause of this difference.
    The petitioner cited evidence for the existence of a genetic 
difference between the Scott and Waddell Creeks coho salmon populations 
and other coho salmon populations in California.
    However, the results from the genetic study cited by the petitioner 
showed that the greatest differentiation, though quite low, was between 
Scott Creek and Waddell Creek, the two California populations that are 
in the closest proximity. The results from the limited number of 
allozyme studies conducted on coho salmon populations in California are 
similar to those obtained for coho populations in Oregon, Washington, 
and British Columbia. Little pattern in the distribution of variant 
alleles or genetic variation was observed, and only weak associations 
between genetic identity and geographic location were found. The 
estimated average number of individuals exchanging genes among the 
California populations of coho salmon studied was greater than 1.0 fish 
per generation, which is large enough to prevent the tendency for 
fixation of different alleles in different populations. Overall, the 
genetic data compiled for this status review failed to demonstrate that 
the Scott and Waddell Creeks coho salmon populations as a group are 
distinct from other coastal coho salmon populations.

Evolutionary Significance

    NMFS considered information provided by the petitioner on 
distinctive differences in habitat characteristics and life history 
traits between Scott and Waddell Creeks coho salmon and other 
California coho salmon populations, as well as the effects of hatchery 
influence on these populations. Distinctive differences in habitat 
characteristics included spawning in habitats characterized by highly 
mobile sediment bedloads and extreme hydrological cycles. Distinctive 
life history characteristics included the reduced number of eggs 
produced by female coho salmon that spawn in Scott and Waddell Creeks.
    Many of the habitat characteristics and life history traits 
exhibited by coho salmon in Scott and Waddell Creeks are found in other 
coho salmon populations in California. Many of the streams and rivers 
in California exhibit similar elevated summer/fall water temperatures 
and extreme winter-flow bedload movements and hydrologic cycles. The 
extreme hydrologic cycles and resultant bedload movement found in Scott 
and Waddell Creeks undoubtedly affect the success of early spawning 
coho salmon in these watersheds. However, these conditions are similar 
to those found in most of California's coastal streams and rivers. 
Excessive use or diversion of drought limited flows in Scott and 
Waddell Creeks, as well as other systems, has probably exacerbated the 
problems created by poor land use management and stream habitat 
conditions.
    Also, we have no data to indicate that Scott and Waddell Creeks 
coho salmon egg production is related to the smaller average size of 
these fish in comparison to other coastal coho salmon populations. The 
number of eggs produced by a female coho salmon, in and by itself, does 
not indicate that there are differences between populations from other 
watersheds. Each river system is highly variable in year to year 
production and a smaller size of adult spawner may result from the 
overharvesting of larger individuals. The number of eggs produced by 
Scott Creek and Waddell Creek coho salmon were within the range 
reported from other coho salmon populations along the entire west 
coast.
    NMFS found some records of hatchery releases of other coho salmon 
stocks into Scott and Waddell Creeks, as well as most of the central 
California coastal streams, from the early 1900's through the early 
1970's. The limited number of fish stocking records indicated that 
Scott and Waddell Creeks were planted with approximately a total of 
500,000 and 130,000 coho salmon fry and juveniles, respectively, from 
numerous other watersheds. More than 2,000,000 coho salmon fry and 
juveniles have been planted in Santa Cruz County streams with coho 
salmon stocks from Washington, Oregon, and northern California. The 
magnitude (and likely effect) of early coho salmon fry releases was 
probably fairly small. However, starting in the 1950's, extensive 
juvenile coho salmon plants began. Even though Scott and Waddell Creeks 
have not been planted with outside sources of coho salmon since the 
early to mid-1970's, the effects of continuous hatchery plants prior to 
that time may have affected any distinctive phenotypic and life history 
traits that originally existed in these populations.

Conclusion

    After a thorough analysis of all information available, NMFS has 
determined that the Scott and Waddell Creeks coho salmon populations do 
not represent a ``species'' under the ESA. Therefore, a proposal to 
list these populations under the ESA is not warranted at this time. 
However, these populations may be part of a larger ESU whose extent has 
not yet been determined. Whether this larger ESU merits protection 
under the ESA cannot be determined at this time. NMFS will attempt to 
identify the larger ESU that contains the Scott and Waddell Creeks coho 
salmon populations as part of an ongoing status review of all coastal 
coho salmon populations in California, Oregon, Washington, and Idaho. 
This status review is being conducted in response to a petition 
received July 21, 1993, to list five stocks of coho salmon in Oregon 
and a petition received October 20, 1993, to list all coho salmon 
stocks in California, Oregon, Washington, and Idaho.

    Dated: April 19, 1994.
Nancy Foster,
Deputy Assistant Administrator for Fisheries, National Marine Fisheries 
Service.
[FR Doc. 94-9995 Filed 4-25-94; 8:45 am]
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