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Sockeye salmon in the Ozette
Lake Basin comprise a unique stock that is genetically distinct from all
other sockeye populations on the Washington coast and in Puget Sound.
Mature adults return to freshwater during an extended period from spring
through late summer, and spawn at two primary locations along eastern
and western lakeshore areas at the southern end of the lake, and in Umbrella
Creek and Big River. Post-emergent fry rear in the lake for a year before
undergoing smoltification and emigrating to marine waters. The lake is
highly productive and out-migrant yearling smolts are unusually large,
averaging 4 ½ to 5 inches in length Smolts produced in Ozette Lake
are documented as the third largest among west coast sockeye populations
examined for average smolt size.
Adults of this stock return
to Ozette Lake in the late spring and early summer months predominantly
as four-year-old individuals. However, three- or five-year-old adult fish
are occasionally observed in the return. The most recent age composition
analyses revealed that 80 of 81 adult sockeye in 1994 were four-year-olds
(one was a five-year-old), and 71 of 71 (100%) in 1998 were four-year-old
fish.
Adult sockeye salmon hold in
Ozette Lake up to six months prior to spawning. The majority of spawners
at both lake beaches and in the tributaries begin spawning by late-October
to early-November and complete spawning by late-November to early-December,
annually. The two principle shoreline spawning areas for Ozette Lake sockeye
are Olsen's Beach, located on the lake's eastern shore north of Siwash
Creek, and Allen's Bay Beach, located on the lake's western shore. Mature
adult sockeye salmon in Ozette Lake have also been reported near the south
shore of Baby Island at the southern end of the lake, in Erickson's Bay,
and on the beach north of Umbrella Creek. Historically, it is likely that
sockeye salmon also spawned in tributaries to Ozette Lake, potentially
including Big River, Umbrella Creek, and Crooked Creek, and in the Ozette
River.
The historical abundance of
Ozette Lake sockeye salmon is poorly documented. However, the overall
abundance of naturally-produced Ozette Lake sockeye salmon is believed
to have declined substantially from historical levels. The first estimates
of escapement of Ozette Lake sockeye salmon occurred in the early 1940s,
and the run sizes entering the lake were estimated at a level of several
thousand fish. These counts appear to be roughly double the current mean
lake abundance, considering that they were likely conducted upstream from
fisheries in or near to the Ozette River. Recent year sockeye salmon escapements
have averaged below 1,000 adults per year, with low years dropping to
only a few hundred fish.
The Ozette Lake sockeye salmon population was listed as a threatened Evolutionarily
Significant Unit (ESU) under the ESA on March 25, 1999. In making this
determination, NMFS concluded that the ESU was likely to become endangered
in the foreseeable future if present conditions continue. NMFS also concluded
that current protective efforts were insufficient to forestall the risk
of extinction. The listed sockeye salmon ESU includes all naturally spawned
sockeye salmon residing below impassable natural barriers in Ozette Lake
and its tributaries. The sockeye salmon reared at the Makah Tribe's Umbrella
Creek Hatchery were considered part of the ESU, but were not considered
essential for recovery of the ESU. NMFS determined that it is presently
not necessary to consider the progeny of intentional hatchery/wild or
wild/wild crosses produced through the Makah Tribal hatchery program as
listed under the ESA. However, once the hatchery fish return and spawn
in the wild, their progeny become listed. For more information, see the Lake Ozette Sockeye ESA Recovery Plan.
There has been no harvest of
Ozette Lake sockeye salmon for the past four brood cycle years (16 years).
Prior to that time, in the 1970s and early 1980s, ceremonial and subsistence
harvests by the Makah Tribe were low, ranging from 0 to 84 fish per year.
Over the 10 years prior to the early 1970s, commercial harvests by the
Makah Tribe remained minimal, averaging less than 500 fish per year. Harvest
has not been an important mortality factor for the population in over
35 years. In addition, due to the early river entry timing of returning
Ozette Lake sockeye salmon (beginning in late-April, with peak returns
prior to late-May or mid-June), the fish are not intercepted in Canadian
and U.S. marine area fisheries directed at Fraser River sockeye salmon.
There are currently no known marine area harvest impacts on Ozette Lake
sockeye salmon
A multitude of factors likely
contributed to the current, depressed abundance status of Ozette Lake
sockeye salmon. Poor marine survival caused by natural environmental fluctuations
was likely an important causative factor for the population decline. However,
the decline in productivity of Ozette Lake sockeye is thought to be primarily
attributed to reduced area and quality of spawning and incubation habitat.
It is clear that anthropogenic factors have considerably altered critical
freshwater habitat, and also played an important role in the decline of
the stock.
Factors responsible for the
decline of Ozette Lake sockeye salmon are thought to include:
- loss of adequate quality
and quantity of spawning habitat;
- predation and disruption
of natural predatorprey relationships;
- introduction of non-native
fish and plant species;
- past over-exploitation in
fisheries;
- poor marine survival; and
- the synergistic cumulative
effects of these factors.
In the tributaries and on certain
lake beaches, these factors are believed to have resulted in extirpation
of locally adapted spawning aggregations and of life history strategies
necessary for successful spawning.
Recent run size estimates and
analysis of previous estimation methods indicate that Ozette sockeye abundance
may currently be relatively stable or increasing, presumably with the
help of the hatchery supplementation and reintroduction program. The adult
sockeye salmon return to Umbrella Creek established through Makah Tribal
hatchery juvenile fish releases has contributed to overall sockeye salmon
abundance in recent years. Tributary adult returns averaged more than
10% of the total run size from 1995 to 1999, and comprised approximately
50% of the large return in 2000 of 4,400 sockeye salmon. In 1999, natural-origin
recruit sockeye salmon spawners were approximately 40% of the total estimated
Umbrella Creek escapement of 400 fish.
Additional Reading
Dlugokenski,
C.E., W.H. Bradshaw, and S.R. Hager. 1981. An investigation of the limiting
factors to Ozette Lake sockeye salmon production and a plan for their
restoration. U.S. Fish and Wildlife Service, Fisheries Assistance Office,
Olympia, WA. 52 p.
Gustafson, R.G.,
T.C. Wainwright, G.A. Winans, F.W. Waknitz, L.T. Parker, and R.S.Waples.
1997. Status review of sockeye salmon from Washington and Oregon. U.S.
Department of Commerce, NOAA Tech. Memo. NMFS-NWFSC-33. 282 p.
Jacobs, R., G. Larson,
J. Meyer, N. Currence, J. Hinton, M. Adkison, R. Burger, H. Geiger, and
L. Lestelle. 1996. The sockeye salmon Oncorhynchus nerka population in
Ozette Lake, Washington, USA. U.S. Department. Interior, NPS Tech. Report
NPS /CCSOSU /NRTR-96 /04. 140 p.
Makah Fisheries Management
(MFM). 2000. Lake Ozette sockeye - hatchery and genetic management plan
- Biological assessment, section 7 consultation. October 23, 2000. Prepared
by Makah Fisheries Management for Bureau of Indian Affairs. Makah Indian
Tribe. Neah Bay, WA. 219 p.
NMFS. 2001c. Resource
management plan - ESA 4(d) Rule preliminary evaluation and recommended
determination: Ozette Lake sockeye salmon resource management plan: hatchery
and genetic management plan component. Draft evaluation of plan provided
by the Makah Tribe (for the Bureau of Indian Affairs), and the Washington
Department of Fish and Wildlife on October 30, 2000. Sustainable Fisheries
Division, National Marine Fisheries Service, Northwest Region. Portland,
OR. 54 p.
NMFS. 2002. Environmental
assessment to analyze impacts of NMFS' determination that the Ozette Lake
sockeye salmon resource management plan addresses section 4(d) limit 6
criteria and does not appreciably reduce the likelihood of survival and
recovery of Ozette Lake sockeye salmon listed under the Endangered Species
Act. Draft document (May 29, 2002). Sustainable Fisheries Division, National
Marine Fisheries Service, Northwest Region. Portland, OR. 51 p.
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