Category: Chinook Sentinel Program

Estimation of Fraser River – South Thompson Age 0.3 Chinook Aggregate Escapement

The goal of the project is to estimate the spawning escapement of the Fraser River – South Thompson age 0.3 aggregate (ST0.3A Chinook). The ST0.3A escapement will be estimated using Coded Wire Tags (CWT), Genetic Stock Identification (GSI), and CWT exploitation rate indicator stock data from escapement and Fraser River fisheries. To achieve this objective, we will increase recovery of CWTs from Chinook carcasses in the Lower Shuswap River; conduct a high-precision mark-recapture project and CWT sampling in the Middle Shuswap River; collect age samples across the South Thompson watershed; produce a CWT release group of Middle Shuswap River smolts (to augment the Lower Shuswap indicator stock); and analyze GSI and age data from the Albion Test Fishery.


Increased Chinook Salmon Stock Coded-Wire Tagging to Improve the Quality of Chinook Indicator Stock Analyses

We propose to maintain increased coded-wire tagging (CWT) for nine Chinook indicator stocks in B.C. that contribute to Northern and Southern Boundary Area fisheries. This proposal will fund incremental tagging beyond the base level provided by the Canadian Department of Fisheries and Oceans (DFO) in order to meet standards derived by the PSC CWT work group to account for survival rate, fishery sampling rate, exploitation rate, and an 80% probability of attaining a minimum standard of observed CWT recoveries. This work has been funded through the Pacific Salmon Treaty (PST) Coded Wire Tag Improvement Fund from 2009-2013, and the PSC Northern Endowment Fund and as a Very High Priority Chinook project in 2014-2016. This project proposes to maintain the increased tagging rates on the highest priority indicator stocks through to 2018, until which time CWTs will be the primary fishery assessment tool for Chinook salmon. This proposal addresses several priorities for implementation of the PST and will improve the ability to better manage the Chinook stocks and fisheries of relevance to the PST.

This proposal is for stocks providing the majority of benefits, based on total fishing mortality distribution, to Northern and Southern Boundary Area fisheries. This proposal addresses nine stock groups represented by CWT indicator programs on Robertson (WCVI), Quinsam (Upper Georgia Strait), Lower Shuswap and Nicola (Fraser Early), Atnarko (Central Coast), Kitsumkalum (North Coast), Harrison and Chilliwack (Fraser Late), and Cowichan (lower Georgia Strait) populations. When these stocks are healthy and abundant they can be large contributors to Southeast Alaska (SEAK), Northern British Columbia (NBC) and West Coast Vancouver Island (WCVI) fisheries.



Burman River Chinook Salmon Mark-Recapture

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.



Chinook Salmon Escapement Estimation to the Skeena River Using Genetic Techniques

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.



Genetic Stock Identification of Chinook Salmon Caught in Northern British Columbia Troll Fisheries

This project consists of the collection and analyses of genetic samples of Chinook salmon caught by the Northern British Columbia Troll fishery each season. The troll fishery typically has the largest annual catch of Chinook salmon in Northern British Columbia, and is managed within the aggregate abundance based management (AABM) regime described in the Pacific Salmon Treaty (1999). The Haida Gwaii (QCI) sport fishery is included within the regime. The sport fishery receives a priority allocation, but the troll fishery typically harvests more Chinook salmon than the sport fishery when operating in the absence of domestic constraints. Genetic samples of Northern BC Troll Chinook catch are a key component of Canada’s domestic fishery management to avoid stocks of concern. Genetic analyses of tissues collected from this fishery allow for estimates of stock specific impacts and comparison to coded wire tag estimates of stock contributions to this fishery. These data are useful to the assignment of Chinook mortalities for the purposes of specific stock management (e.g. WCVI Chinook or local concerns for Yakoun River or Kwinamass River Chinook) and for accounting of Nisga’a Treaty entitlements. The data are also used to generate escapement and terminal run size estimates for stocks or stock groups with representative coded wire tagged components.


Genetic-Based Abundance Estimates for Snohomish River Chinook Salmon

This project, begun in 2012 by the Washington Department of Fish and Wildlife under the Sentinel Stocks Program to estimate the abundance of Chinook salmon spawners and effective breeders in the Snohomish River, continues today in partnership with the Tulalip Tribes of Washington using trans-generational genetic mark recapture (tGMR) and trans-generational rarefaction curve analysis (tRC). Additional objectives are to partition the genetic-based abundance estimate for natural spawning Chinook by origin, sex, and age, and assuming adequate data are acquired, and to develop a redd expansion calibration factor to adjust historical (or future) redd-based escapement estimates.
Funding is requested to collect and genotype subyearling offspring of the previous brood year, and to collect carcass samples from spawners in the fall. The Snohomish River basin is comprised of two Chinook salmon populations: the Skykomish River summer Chinook population (which includes Skykomish, mainstem Snohomish, and Pilchuck River) and the Snoqualmie River fall Chinook population. We expect to deliver tGMR and tRC abundance estimates for both populations for each brood year that is successfully sampled.

Abundance Estimates for Stillaguamish River Chinook Salmon Using Trans-generational Genetic Mark Recapture

The primary objective of this trans-generational genetic mark-recapture (tGMR) project is to: 1) estimate the abundance of Chinook salmon spawners and effective breeders in the Stillaguamish River above the smolt trap site using genetic abundance methods. The secondary objectives of this study are to: 2) estimate the natural spawning Chinook salmon abundance by origin (hatchery or natural), sex and age, and 3) estimate a redd expansion calibration factor from historic redd-based escapement estimates and possible future redd counts. The data collected for this project also provide a genetic baseline for these population estimates, a genetic (parentage-based) estimate of the proportion of hatchery-origin spawners, and an estimate of relative reproductive success of hatchery spawners, because carcasses are classified by origin. Genetic sampling will be conducted during the fall spawning period, and smolt trapping will be conducted during the following spring.



Chilko River Chinook Salmon Mark-Recapture (Fraser River Summer-run Age 1.3 Stock Group)

The primary goals of the Chilko River Chinook Salmon Mark-Recapture Project are to develop and estimate the spawning abundance that meets or exceeds the Chinook Technical Committee data standard for escapement indicator stocks. Specifically to determine:

1) estimates of spawning escapement by age and sex that will, on average, attain a coefficient of variation (CV) of 15% or less on the spawner estimates; and

2) consistent estimates that are asymptotically unbiased.

Additional objectives include bias testing of application and recovery data, and improving the efficiency of the study in-season and annually.

Radio Telemetry Investigation to Test Closure Assumptions Underpinning Escapement Estimates for the Harrison Stock (Fraser River Fall-run Age 0.3 Stock Group)

Canadian Department of Fisheries and Oceans (CDFO) Fraser Stock Assessment have been delivering a high-precision Chinook salmon mark-recapture program on the Harrison River since 1983. The Harrison River mark-recapture project is the escapement indicator stock for the Fraser River Fall stock group. Program staff also conduct a SSP mark recapture on Chilko River and annual mark-recapture programs on the Lower Shuswap, Middle Shuswap and Nicola rivers; which generate highly precise (CV < 15%) escapement estimates by age, sex, and hatchery contribution. CDFO staff have considerable expertise in the delivery of telemetric assessments of fish behaviour to determine whether or not assumptions of distribution and closure have been met. Fraser Stock Assessment staff have successfully conducted similar telemetry studies on the Lower Shuswap, Middle Shuswap and Chilko rivers.
The Chilliwack River exploitation rate indicator stock is used to represent the distribution of the Harrison Chinook stock. The mortality distributions from the CTC exploitation rate analysis, shows that the stock occurs mainly in the West Coast Vancouver Island (WCVI) aggregate abundance based management (AABM) fishery and US and Canadian individual stock based management (ISBM) fisheries. The stock has high fishery management importance because of its large exploitation in the WCVI AABM, US ISBM and Canadian ISBM fisheries and large abundance.