[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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