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Blue
Creek is the largest and most pristine tributary in the Lower Klamath
Sub-basin and correspondingly supports the largest anadromous fish
populations in the sub-basin. In a 1979 report detailing the status of
anadromous stocks within the Hoopa Valley Reservation (then including
the present day Yurok Indian Reservation and representing all
tributaries within the lower Klamath and lower Trinity Rivers), the U.S.
Fish and Wildlife Service (USFWS) found Blue Creek to have “the
greatest potential to support anadromous fish of any tributary on the
reservation” (USFWS 1979).
The Blue Creek Chinook stock is referred to as a late-fall Chinook run
due to its typical November-December run timing and is considered to be a
unique stock specifically adapted to the lower Klamath River and its
tributaries (Anglin 1994). Gall et al. (1989) found Blue Creek fish to
be more similar genetically to Smith River or Southern Oregon stocks
than to other Klamath groups, while Snyder (1931) noted this unique run
timing, finding Blue Creek fish to be much more similar to Smith River
fish terms of body size, shape, and coloration.
Blue Creek also supports one of the largest remaining coho salmon run in
the Lower Klamath Sub-basin. In particular, the Crescent City Fork
provides ideal spawning and rearing habitat for coho salmon and in most
years is more heavily utilized by coho salmon in its upper reaches than
any other salmonids species. Given Blue Creek’s relatively pristine
habitat and its isolation from other wild coho refugia, the Blue Creek
coho stock appears to be an important genetic refuge for wild coho
populations in the Klamath River Basin.
Stream assessment data collected by the Yurok Tribal Fisheries Program
(YTFP) during 1995-2004, as well as data collected by USFWS during
1988-1993, indicate that late-fall run Chinook and coho salmon are
either non-existent or are present in relatively low numbers in the
remaining lower Klamath River tributaries (Lintz and Kisanuki 1992;
Lintz and Noble 1992; Noble and Lintz 1190; Voight and gale 1998; YTFP
unpublished data 1994-2004). The ongoing monitoring of the Blue Creek
salmon populations is therefore essential in order to assess the status
of this unique resource.
This project, initiated by USFWS in FY 1989, is designed to collect
adult chinook escapement data for the Blue Creek basin. This data
allows for an assessment of chinook population trends within the basin
as well as Chinook and coho salmon distribution, immigration/emigration
timing, and habitat usage throughout the Blue Creek drainage. The
Chinook trend data is an integral component of the Mega-Table and allows
for a more accurate assessment of wild salmonids population numbers
throughout the Klamath Basin, which in turn allows for more accurate
predictions of future Chinook run sizes.
This project also collects coho salmon data to the extent possible;
however surveys are often complete prior to the time that most coho
salmon spawning is expected to occur in Blue Creek. The duration of
surveys into late December/January is not only limited by budget, but
often times by high flow conditions in the stream. Information
collected through this project also allows for more meaningful and
informed input into land management activities within the basin as well
as future watershed restoration activities.
Project Objectives:
The objectives of this project are to:
Generate a fall 2010 fall Chinook spawner index count for adult Chinook
salmon using peak weekly snorkel survey counts of adult fall chinook.
• Marking of fall Chinook will occur, which combined with snorkel
surveys will allow for an estimation of the fall Chinook population
abundance using the “area under the curve” methodology. The success of
this methodology is largely dependent on stream conditions.
• Several years of successfully producing “area under the curve”
population estimates and spawner index survey estimates simultaneously
should enable analysis of the relationship between the “area under the
curve estimates” and the spawner abundance index count estimates. This
could provide two benefits:
1. Application of this relationship to spawner survey index count data
that has been collected since the early 1990’s, allowing an expansion of
this information into population estimates.
2. Application of the relationship to spawner index survey count
information in the future, so population abundance may be able to be
estimated during years when “area under the curve” estimates are not
available.
• Determine the extent of Chinook salmon immigration and spawning within
the Blue Creek basin during the fall/winter 2010-2011. This will
include an assessment of timing, distribution and run size, as well as
documenting the quantity, timing and distribution of redds and carcasses
by species.
• Provide Tribal Fisheries Biologists with the necessary data to provide
informed input into Lower Klamath resource management planning, habitat
restoration planning and implementation, and ESA-related recovery
planning and viability analysis.
• Improve the skills and knowledge of YTFP employees/Yurok Tribal
members through hands-on experience conducting a diversity of fisheries
monitoring projects.
This agreement will benefit the public by the information collected from
this large cooperative effort is used to track population trends and
estimate the fall Chinook ocean stock abundance, age composition, and
spawning run size, which are needed by the Pacific Fishery Management
Council (PFMC), California Fish and Game Commission and Tribes for
harvest management. The information is used to determine if the PFMC
Conservation Goal for Klamath River fall Chinook is met in a particular
year, and to develop projections of the fishable stock for the upcoming
year. Once those projections are made, they are used by fishery
management agencies to promulgate fishing regulations for the Chinook
salmon fishery along the southern Oregon coasts.
Task 1 – Generate a fall 2010 escapement estimate for adult Chinook
using the area-under-the-curve methodology.
Task 2 – Generate a fall 2010 fall Chinook spawner index count for
adult Chinook salmon using peak weekly snorkel survey counts of adult
fall chinook.
Task 3 – Determine the extent of Chinook salmon immigration and spawning
within the Blue Creek basin during the fall/winter 2010/2011.
Task 4 – Provide Tribal Fisheries Biologists with the necessary data to
provide informed input into Lower Klamath resource management planning,
habitat restoration planning and implementation, and ESA-related
recovery planning.
B. METHODS
Adult Fish Marking
Capture Techniques: Fish will be targeted in the lower reaches of Blue
Creek as they move into the system. Capture techniques will include a
3.5 inch mesh tooth tangle net. The net will be fished both passively
and actively drifted depending on the most effective capture method for
existing conditions. A biologist and at least one technician will
remain with the net at all times, while a second biologist and
technician will also be resent to assist with transfer of captured fish
to holding tubes. All captured salmonids will be measured, sex will be
determined by external characteristics when possible, scale samples
taken, marked with a visual streamer tag, secondarily marked with a
fin-clip, allowed to recover, and released upstream. Several marking
events will occur in the lower reaches of Blue Creek. During each event
batch marking will be implemented. All salmonids marked during each
event will receive the same color streamer tag behind the dorsal fin.
Observe Efficiency: Observer efficiency will be defined as the
percentage of adult salmon counted by observers in relation to the
actual number present. (Bocking et al, 1988, Irvine et al. 1993) Known
number of salmon will be marked and allowed to disperse for a minimum
of three hours (Hetrick, personal communication). Two divers will dive
through this block-netted section and count newly marked fish. Physical
parameters that are expected to effect observer efficiency will be
recorded and rated during efficiency trials as well as during all
snorkel surveys.
Residence Time: Residence time will be defined as the average duration
that individuals of a species spend alive in the creek. After marking
events, snorkel surveyors will survey existing/long-term reaches
throughout the anadromous portion of the drainage enumerating marked and
unmarked salmonids by species. Marked fish counts will be corrected
observer efficiency and plotted against time to yield a mark depletion
curve (Hetrick, personal communication). The area under the curve will
be divided by the original number of tags deployed to estimate a
period-specific residence time in days for that time period as described
by Irvine et al. (1992). Due to the fact that throughout the season
residence time will likely vary, an average of the period specific
residence times weighted by abundance will be determined. The weighted
mean residence time will be applied to weekly snorkel counts to generate
a weekly abundance estimate. All weekly estimates will be summed for
the annual escapement estimate.
Spawning Surveys
Spawning surveys will be conducted weekly from October through
mid-December of each year to document immigration and spawning activity
by late-fall Chinook and coho salmon, as well as any steelhead and
coastal cutthroat trout present during this time period. Surveys will
be conducted using direct observation (snorkeling) techniques throughout
the survey periods in order to maximize efficiency of fish
observations, species identification, carcass and redd location etc.
Each reach will be snorkeled by a crew consisting of a Fisheries
biologist and a Fisheries Technician. All crewmembers involved in these
snorkel surveys have extensive snorkeling experience, including several
seasons conducting these inventories within the Blue and Terwer Creek
drainages. Information will be collected on each live fish, redd, and
carcass located as follows:
Live Fish
• Species, number and exact locations observed
• Size, condition and sex of each observed fish as feasible
• Presence of any clips, marks, scars, etc.
Redds
• Exact location where observed
• Species and number of fish present (if any)
• Habitat type where observed
• Dimensions of redd (length, width, pt depth, mound depth)
• Each redd flagged as downstream end to prevent counting on future
surveys
Carcasses
• Exact location where observed
• Species, fork length and sex
• Percent spawned
• Collect scales
• Presence of any clips, marks, scars etc, and collect head if
ad-clipped
• Condition (fresh/rotten, whole/partial etc.)
• Flag carcass through gills to prevent counting on future surveys
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