Tag Archives: spawning ground surveys

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.



Calibration of Assessment Methods for Fraser Sockeye Enumeration

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.


Northern Boundary Area Summer Chum Salmon Monitoring

The purpose of this project is to improve assessment of summer chum salmon escapements in the northern boundary area of southern Southeast Alaska. The Alaska Department of Fish and Game currently maintains an escapement index of 13 summer-run chum salmon streams in the Boundary Area that are assessed primarily through aerial survey methods. Two additional index streams were identified during the first two years of this project, including one that was suitable for conducting long-term foot and aerial surveys. These streams were added to the Southern Southeast Subregion summer chum salmon escapement index during the Alaska Board of Fisheries meeting in February 2015. ADF&G Commercial Fisheries managers have expressed concern regarding their ability to obtain reliable counts of chum salmon in some of the large mainland rivers where chum salmon may be masked by high densities of pink salmon, particularly in years of low chum salmon abundance. The primary objective of this project is to conduct helicopter surveys of summer chum salmon on currently monitored, large mainland river systems south of Wrangell and one new index stream on Prince of Wales Island. Helicopter surveys will provide surveyors improved views of these streams, validate observations of chum and pink salmon abundance, identify primary chum salmon spawning areas, and improve managers’ ability to identify chum salmon during routine aerial surveys of other index streams in the area. Additional foot and aerial surveys conducted concurrently on three smaller chum salmon index systems will similarly allow for direct comparison to aerial survey estimates. Results from these surveys will guide future chum salmon monitoring in the boundary area. In addition, we will opportunistically collect tissue samples from pink and chum salmon for Southeast Alaska genetic baselines as needed.


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.



Atnarko River Chinook Escapement Estimation

The Atnarko River was identified as a potential escapement and exploitation rate indicator for Central BC early summer Chinook, and in 2009 the Atnarko River Chinook stock was proposed as an exploitation rate indicator. It was funded under the Coded Wire Tag (CWT) Improvement program, and the purpose of the five-year mark-recapture program was to improve escapement estimates for early summer Chinook.
Since then, the program has met the data standard of a coefficient of variation (CV) of 15% or less. Continued mark-recapture estimates on the Atnarko River will build on the information thus far. The project will estimate the escapement of Chinook salmon and generate estimates such that the fraction of CWT fish is known relative to the wild and/or unmarked escapement, and this data is essential for Chinook run reconstruction calculations. This program is part of a comprehensive group of programs on Atnarko River Chinook salmon that includes the production of Chinook fry and CWT application (under separate submission to the Northern Fund) and terminal fishery monitoring.