This Asotin Creek
2005 Annual Report includes the data collected under two contract
periods: Contract No. 00018229, covering the period from June 1, 2004
to May 31, 2005, and Contract No. 00022720, covering the period from
June 1, 2005 to December 31, 2005. The Asotin Creek 2004 Annual Report
was submitted to BPA on November 23, 2004, as a deliverable under
Contract No. 00014059. The FY04 Annual Report did not include data
from the fall of 2004, which was subsequently covered in the FY05
contract, due to a change in contract period, and to changes in the
BPA work element (statement of work) process and reporting requirements.
All populations
of anadromous salmonids in the Snake River have been listed as threatened
under the Endangered Species Act (ESA) by the National Marine Fisheries
Service, including steelhead (Oncorhynchus mykiss) and spring/summer
Chinook salmon (O. tshawytscha). Bull trout (Salvelinus
confluentus) have been listed as threatened by the U.S. Fish
and Wildlife Service. Historically, Asotin Creek supported summer
steelhead, spring Chinook salmon, fall Chinook salmon, bull trout,
and lamprey sp. (Petromyzontidae). The Washington Department
of Fish and Wildlife (WDFW) designated the Asotin Creek Subbasin a
wild steelhead refuge in 1997 and has planted no hatchery fish in
Asotin Creek since 1998. Limited, but continuous, efforts have been
made to assess salmonid populations in the Subbasin since 1984.
Critical uncertainties
must be answered if populations are to be rebuilt and de-listed. Such
uncertainties may include habitat/life history stage relationships,
causal relationships for degraded habitat and depressed or extirpated
populations, and understanding the relationship between resident and
anadromous O. mykiss subpopulations (ASP 204, p. 173). Critical uncertainties
for the Asotin Creek Subbasin include: 1) Is the steelhead population
parent-to-progeny ratio above the replacement [>1.0]? 2) How can
managers intervene to rebuild steelhead populations that may be at
marginally successful productivity above eight FCRPS dams, if necessary?
3) Are bull trout functionally extinct, and if not, does the migrating
life form still exist in the basin? And 4) Can habitat recovery efforts
and careful use of hatchery-produced spring Chinook salmon effectively
reestablish a self-sustaining population of spring Chinook salmon
in Asotin Creek? (ASP 2004, p. 173; ASP, App. M, p. 3).
The genetic nature
of naturally-producing (presumed wild origin) salmonids in the Snake
River Basin is a critical concern under the ESA. This project provides
the opportunity to contribute tissue samples to regional efforts to
better describe steelhead and bull trout, and potentially to determine
the origin of spring Chinook salmon that may be using Asotin Creek
opportunistically. Samples from this project, coupled with genetic
sampling in adjacent subbasins, will aid in understanding the effect
of lower Snake River hatchery supplementation, and describe population
genetic similarities and differences for recovery planning. Understanding
the origin and genetic composition of colonizing stray hatchery or
natural-origin spring Chinook salmon will be critical in developing
a spring Chinook salmon reintroduction plan that managers have identified
as a priority for the Asotin Creek Subbasin (ASP 2004, p. 162).
This project also
implements reasonable and prudent alternative (RPA) 180 in the NMFS
2000 and Action 180 in the 2004 Federal Columbia River Power System
(FCRPS) Biological Opinions (BiOp) for a basin-wide hierarchical monitoring
program. This program is expected to determine population and environmental
status (including assessment of performance measures and standards),
and review of status change over time. The Asotin Assessment project
was selected for implementation under this RPA in 2002 with full funding
beginning in 2004.
The WDFW and the
NOAA Fisheries Interior Columbia Technical Recovery Team (TRT) considers
the population of spring Chinook salmon to be functionally extinct
in Asotin Creek. However, 1,884 juvenile Chinook salmon were captured
during the spring of 2004 near Headgate Dam (near river km (rkm) 14.5),
which provided a population estimate of 4,121 juvenile Chinook salmon
emigrating from the Asotin Creek Subbasin (Schuck and Mayer 2004).
This suggests that spring Chinook salmon can spawn successfully in
Asotin Creek, but there is insufficient information to infer a re-established
population.
Bull trout populations
in the Columbia River Basin were listed as threatened in June 1998.
The Asotin Creek population is part of the Columbia Basin Distinct
Population Segment (DPS) for bull trout. Although once believed to
be nearly extinct in the basin, redd surveys conducted by the U.S.
Forest Service (USFS) found bull trout spawning in the upper North
Fork Asotin Creek in 1996 (D. Groat, USFS, pers. comm.). Since that
time, the USFS and WDFW have conducted bull trout spawning surveys
in portions of the upper North and South forks of Asotin Creek. Four
juvenile bull trout were captured in the Project’s smolt trap
in 2004.
Despite the extirpation
of spring Chinook salmon and near loss of bull trout, there is currently
a significant population of naturally producing steelhead in Asotin
Creek. We captured 8,028 juvenile steelhead in the Project’s
smolt trap during the spring of 2004 (Schuck and Mayer 2004). The
estimated population of juvenile steelhead from the spring 2004 migration
season was 43,457 (95% CI = 37,972 – 48,942 juveniles), which
was about 1,129 juveniles per rkm (1,818 juveniles per mile), above
the spring 2004 trapping site near rkm 14.5.
This project is
a logical extension of limited past and present biological monitoring
efforts in the Asotin Creek Subbasin. The expanded baseline data collected
for each focal species under this project is needed to refine fish
return and management goals, and to assist in the establishment of
future numeric fish population goals as outlined in the Asotin Subbasin
Plan (ASP 2004, p. 160). In addition, assessing the Asotin Creek steelhead
population may provide a better understanding of limiting factors
that affect similar or adjacent populations. Moreover, data from this
project could be used to help determine if regional recovery efforts
to stabilize and rebuild steelhead populations would be best spent
on within-subbasin projects or out-of subbasin actions (i.e., FCRPS
modifications). Rebuilding the bull trout population and eventually
reintroducing spring Chinook are goals for the Subbasin.
The goal of this
project is to determine the abundance and current productivity of
anadromous adult and juvenile salmonids in Asotin Creek (primarily
summer steelhead) above George Creek, and to estimate life stage survival
rates. This project implements the research, monitoring and evaluation
(RM&E) criteria specified in the Asotin Subbasin Plan (ASP 2004),
by providing estimates of abundance, productivity, survival rates,
and additional information on temporal and spatial distribution of
ESA-listed species, primarily summer steelhead, and secondarily spring
Chinook salmon. In addition, this project will document the abundance
and migratory behavior of bull trout captured at the trapping locations,
by counting, sampling and tagging bull trout with passive integrated
transponder (PIT) tags. Estimates of smolt-to-adult and adult-to-adult
survival for the natural steelhead population in Asotin Creek will
provide the data necessary to help determine if salmonid production
in the subbasin is being limited by within- or out-of-basin factors.
The objectives
for this project are:
- Objective 1:
Document juvenile steelhead life history patterns, survival rate
and smolt production in the Asotin Creek watershed above George
Creek.
- Objective
2: Estimate escapement of hatchery and wild steelhead and salmon
into the Asotin Creek watershed above George Creek; Measure adult
trap fallback and adult trap capture efficiency.
- Objective 3:
Estimate spawner abundance and adults per redd.
- Objective 4:
Collect genetic samples.
