Tag Archives: Escapement Estimate

Automating procedures for the forecasting of terminal run and escapement of Chinook, coho and chum salmon stocks using open-source statistical software

The annual exercise of forecasting terminal run or escapement is a critical aspect of management and conservation of salmonids coastwide. This project involves the completion of an automated computer program (henceforth called “ForecastR”) relying on the open-source statistical software R to generate age-specific forecasts using a variety of generic models including (i) simple and complex sibling regressions with the ability to include environmental covariates, (ii) time series models such as ARIMA, exponential smoothing, and naïve models, and (iii) mechanistic models such as average return rate models that depend on auxiliary data such as the number of outmigrant juveniles, the number of hatchery fish released or the number of spawners.

 

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.

 

 

Albion-based Estimate of Total Fraser River Chum Escapement Using GSI and Estimate of Chilliwack River Chum Escapement

We propose to enumerate total Fraser River chum salmon escapement by conducting a high precision enumeration project on Chilliwack River escapement (e.g. mark-recapture or DIDSON) and combining the result with the ratio of Chilliwack chum to the total Fraser chum captured in the Albion test fishery. The proportion of Chilliwack chum at Albion will be determined using GSI on tissue from scale samples already collected during the test fishery.
This project will improve our ability to provide accurate spawning escapement estimates for Fraser River chum salmon. Accurate estimates are important to all aspects of Fraser River chum salmon management including annual stock run reconstruction, production forecasting, in-season terminal abundance estimates, the evaluation of management decisions/actions, and harvest sharing.

 

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.

 

 

Boundary Area Coho Escapement

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.

 

Hugh Smith Lake Coho Smolt Enumeration and Marking

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.

Babine Lake Sockeye Smolt Enumeration – Mark-Recapture

The Lake Babine Nation Fisheries Department (LBNF), in collaboration with the DFO, propose to build on success in the smolt project by continuing to operate the Babine smolt enumeration facilities to provide sockeye smolt emigration estimates and smolt fitness data for the Babine Lake Watershed. Smolt production and fitness are effective indicators of Babine Lake ecosystem health which can be used to initiate and direct resource management initiatives intended to protect the Babine Lake watershed. We believe that continuous data from the Babine smolt enumeration fence would provide important information on Babine sockeye population status that will contribute critical information to the understanding the large inter-annual variations in returns observed in the past two decades. An uninterrupted set of sockeye smolt population data over multiple years will help address one of the most fundamental questions of salmon stocks management — under which conditions are freshwater or marine environments the primary driver determining salmon returns?