Concern for West Coast Vancouver Island (WCVI) natural Chinook currently limits PSC fisheries in Southeast Alaska, the Haida Gwaii recreational fishery and particularly the Area F troll fishery in northern British Columbia and troll fisheries and some recreational fisheries on the WCVI. Although the Burman River is enhanced, the population is of sufficient size to estimate the escapement with precision, and thermally marked otolith sampling provides an estimate of the naturally spawned fraction.
The program will estimate the escapement of adult Chinook salmon to the Burman River, a PSC Chinook escapement indicator, using both closed population and open population mark-recapture techniques refined between 2009-2014. The project will also quantify age, sex and origin compositions. Estimates of abundance of the thermally marked hatchery fraction combined with a precise escapement estimate will provide important information to verify and support the WCVI Aggregate ratio estimation project by providing an independent reference point (the Burman River Chinook hatchery fraction, independent of Robertson Creek Hatchery stock) in the northern WCVI area.
The Skeena River is host to the second largest aggregate of Chinook salmon in British Columbia. While the aggregate is a PSC escapement indicator stock, there are no biologically based escapement goals for this population. This project produces an annual escapement estimate for the Skeena River Chinook aggregate and provides information on the stock components that make up the Chinook return to the Skeena River. The project consists of genetic analyses of samples from Chinook salmon caught at the Tyee Test fishery in 2021. The project uses samples and data from two independent programs, the Tyee Test Fishery and the Kitsumkalum mark-recapture program. Chinook salmon scale samples will be collected from the Tyee Test Fishery and the DNA from the samples will be compared against genetic baselines from Skeena Chinook salmon populations. The proportion identified as Kitsumkalum Chinook will be expanded to generate escapement estimates for the Skeena River aggregate using the mark-recapture estimate of escapement for the Kitsumkalum population.
Since 2007, with support from the Southern Boundary Restoration and Enhancement Fund, calibration work has been conducted on twenty-five Sockeye populations of various stream types in the Fraser and has led to the development of indices for aerially surveyed Sockeye populations on the following three stream types: i) medium sized, clear streams, ii) medium sized, partially turbid/tannic streams and iii) large sized, clear streams. Although this represents substantial progress, significant gaps still exist on the remaining stream types and lake spawning populations. Calibration work involves the comparison between estimates generated using high precision enumeration techniques (enumeration fences, sonar, and/or mark-recapture programs) and those generated using standard low precision visual techniques. As annual calibration opportunities on target populations are limited, calibration work over the long term will be required to satisfy the data requirements for all stream types. The actual populations to be calibrated will be determined based on in-season estimates of abundance.
This joint project by NOAA and the University of Alaska Fairbanks evaluates the long term fitness of hatchery and wild sockeye salmon within a small watershed in Southeast Alaska. Concern over preserving wild stock fitness in enhancement project watersheds has been expressed in the case of both the Pacific Salmon Commission (PSC) Transboundary River Plans on the Taku and Stikine Rivers, and the PSC Northern Boundary Treaty Area of Southern Southeast Alaska (Hugh Smith and MacDonald Lakes). Measurement of the fitness effects and potential impact of such enhancement projects is needed to avoid long term undesirable effects on wild stocks. Initial genetic sampling and trial fish culture work in 2008, 2009, and 2010 showed potential for utilizing microsatellite and single nucleotide polymorphism (SNP) markers to assess the parentage of Auke Lake sockeye and to identify the progeny of wild and enhanced fish, and this allows the evaluation of the survival and introgression, if any, of the enhanced fish into the wild population. Furthermore, we have demonstrated the ability to sample very close to 100% of the adult sockeye entering the system and provided a low impact design for sampling, capturing, maturing and spawning small numbers for use as brood stock in this study. During the summers of 2011, 2012 and 2013, we captured and held adult sockeye in the Auke Creek Research hatchery, and conducted experimental matings in all three years. We have incubated, cultured and released approximately 50,000 juvenile sockeye into Auke Lake in the springs of 2012, 2013, and 2014. Complete sampling of upstream migrating adult sockeye has occurred from 2008 thru 2015 and smolt sub-sampling has occurred in May and June of those years as well.
Beginning in 2016, additional objectives were added to cover the sampling, marking and recovery of coho salmon at Auke Creek. Because of the operational efficiencies and base support this was accomplished with a small budget increment. Auke Creek is the longest and most complete coho salmon time series in Southeast Alaska, and is used as an indicator of marine survival, harvest and productivity for coho in the region.
NF-2011-I-10 A Smoker (McPhee)
NF-2008-I-26B Heard (Guyon)
Annual stock-specific run reconstructions (catch plus escapements) are required to accurately estimate relative contribution of each stock caught in Northern Boundary Area fisheries. Estimates of national origin of contributing stocks provides the most reliable information currently available to complete these run reconstructions, and are used to evaluate stock-specific productivity and revise pre-season forecasts. While the catch of Nass and Skeena sockeye salmon is only subject to treaty harvest-sharing annexes in the Alaska District 101 gillnet and Alaska District 104 purse seine fisheries, the harvest of these stocks in all fisheries, and their escapements, needs to be estimated in order to calculate the total run and the percentage caught in the annexed fisheries.
This project will complete genetic stock identification (GSI) analysis on sockeye salmon tissue samples collected from the 2016 commercial purse seine fisheries in Districts 101, 102, and 103 in Southeast Alaska. This project is a complement to the ongoing project at the Auke Bay Laboratory for Northern Boundary Area sockeye salmon GSI in Districts 101 and 104, and continuing work by DFO in Areas 3, 4, and 5; and will allow for complete assessment of the catches of Nass and Skeena sockeye salmon in all major Northern Boundary Area fisheries for run reconstructions. Estimates will be provided for up to 3 time strata in District 101, up to 3 time strata in District 102, and over the entire season in District 103, for a total of 1,500 samples analyzed.
The Hugh Smith Lake coho salmon population is substantially exploited by mixed-stock fisheries in both the U.S. and Canada and is, therefore, a key indicator stock used to monitor total adult abundance and escapements, and the pattern and intensity of exploitation by these fisheries on populations in the northern boundary area. It is the only system in the southern portion of Southeast Alaska where a total count (with back-up mark-recapture estimate) of coho salmon escapement has been routinely collected since 1982. Its location 70 km southeast of Ketchikan makes it a particularly strategic indicator stock for boundary area fisheries. It has also been one of three key indicator stocks used to measure the overall abundance of wild coho salmon available to the Alaska troll fishery and to measure the exploitation rate by the fishery.
Escapement projections are made from both the cumulative weir count and estimation models based on recovery of coded-wire tags to provide real-time information for management of fisheries for escapement. Peak helicopter survey counts at other Boundary Area streams provide an index with greater coverage that complements higher resolution assessment at Hugh Smith Lake.
The Hugh Smith Lake coho salmon population is substantially exploited by mixed-stock fisheries in both the U.S. and Canada and is, therefore, a key indicator stock used to monitor total adult abundance and escapements, and the pattern and intensity of exploitation by these fisheries on populations in the northern Boundary Area. Its location 70 km southeast of Ketchikan makes it a particularly strategic indicator stock for boundary area fisheries. It has also been one of three key coded-wire tagged indicator stocks used to measure the exploitation rate by the Alaska troll fishery and to estimate the overall abundance of wild coho salmon available to the fishery. Timely escapement projections are made from both the cumulative weir count and estimation models based on recovery of coded-wire tags to provide real-time information for management of fisheries for escapement goals.
The Hugh Smith Lake coho salmon population has been the only long-term, continuously operated wild coho indicator stock project in the northern boundary area, with a record of catch, escapement, smolt production, marine survival, and age composition estimates dating from 1982. The proposal would continue to fund operation of a smolt weir to enumerate and coded-wire tag coho salmon smolts emigrating from Hugh Smith Lake to generate total population estimates, including total smolt production, marine survival, exploitation rate, and catch by area, time, and gear type. Coho smolt estimates and tag recovery rates in the Southeast Alaska troll fishery will be used to generate inseason estimates of marine survival and total adult abundance for fishery management. Estimates of brood year smolt production and adult return by age class will be used to evaluate and refine the biological escapement goal. Counts and samples of sockeye salmon smolts are also obtained at the smolt weir and have been used to evaluate escapement goals and effectiveness of sockeye salmon stock enhancement efforts. The proposed project will continue a core stock assessment program needed to manage fisheries for coho salmon in the northern Boundary Area.
Chinook salmon stocks originating from the West Coast of Vancouver Island (WCVI) contribute significantly to the ocean harvests in fisheries in Southeast Alaska and northern British Columbia, as well as being of prime importance to near-shore fisheries along the WCVI itself. Consequently, commercial and sport fishermen, as well as First Nations up and down the coast have a vested interest in the status of WCVI Chinook salmon. Management agencies and organizations responsible for fisheries in Southeast Alaska, northern British Columbia, and along the WCVI have need of stock status information concerning WCVI Chinook salmon.
The overall goal of this project is to estimate the aggregate terminal returns of WCVI hatchery and natural origin Chinook salmon, including catch plus escapement inside the surf line such that the estimates are asymptotically accurate and have a CV of 15% or less. This will be achieved through 1) the first comprehensive assessment of catch plus escapement along the WCVI, and 2) refinement of the ‘driver stock’ approach for estimating aggregate terminal return from a distant fishery.
The “driver stock” approach was first developed through the Sentinel Stock Program, and is based on the assumption that an indicator stock (or stock group) experiences the same exploitation and maturation rates as the aggregate. If the assumption holds, the incidence of this indicator stock group in an ocean fishery (using information such as CWT, otolith, DNA) and in its terminal area would have the same ratio as the catch of the indicator stock group in the same ocean fishery to its terminal run size. When using a single CWT stock, estimating terminal run size is simple. However, given the complexity of the WCVI stock aggregate and terminal WCVI fisheries, the key assumptions of the method – i.e. that maturation rates and exploitation rates are constant across the WCVI aggregate, were not met.
The purpose of this project is to 1) improve the precision of the terminal return estimates of natural and hatchery origin chinook salmon along the WCVI, 2) quantify the variation in maturation, exploitation rates, abundance across the WCVI aggregate, and 3) use the additional information to refine the application of the driver stock approach to the WCVI aggregate through development of a Bayes method. These results will benefit existing stock reconstructions and forecasts in the assessment of the WCVI Chinook salmon stock complex.