Enhanced sockeye salmon outplanted as part of enhancement projects in the Transboundary Rivers area have their otoliths thermally marked as fry to allow later identification to stocking origin and brood year. Transboundary Rivers (TBR) stock assessment and monitoring projects collect otoliths from both outmigrating sockeye smolts and returning sockeye adults through a variety of projects. The proposed thermal mark recovery project will fund the preparation, interpretation and analysis of these samples, which will provide critical data to stock assessment and enhancement activities; wild/enhanced ratios, scale aging validation, fry to smolt survival, smolt to adult survival, contributions of enhanced fish to returns, straying rates, etc. These data are vital elements of Transboundary stock assessment, enhancement, and fishery management programs. Data are used in enhancement planning and evaluation for multiple stocks, forecasting of returns, annual run reconstructions, and monitoring fishery management performance.
The purpose of this project is to augment the ongoing Taku Fishery Sampling and Stock Assessment in support of management as outlined in Chapter 1 of the Pacific Salmon Treaty. The Taku River sockeye salmon stock assessment project has been conducted annually since 1984 and is a cooperative effort between the Alaska Department of Fish and Game (ADF&G), Department of Fisheries and Oceans Canada (DFO), and the Taku River Tlingit First Nation (TRTFN). The objectives of this stock assessment are to provide inseason and postseason estimates of inriver abundance and to document biological characteristics (migratory timing, migratory rates, and age, sex, and size composition) of Taku River sockeye salmon stocks. Spaghetti tagged-to-untagged ratios of salmon harvested in the Canadian inriver gillnet fisheries are used to develop mark-recapture estimates of the inriver abundance of sockeye salmon.
This proposal involves genetic analysis of tissue samples anticipated from the in-river commercial sockeye fishery on the Taku River in 2019. This activity was first supported by the Northern Fund in 2008 and makes use of the baseline samples collected with Northern Fund assistance from 2007-12.
This will identify the composition of the commercial harvest by stock groupings. In addition, when coupled with escapement counts from headwater counting fences (weirs), it will permit estimation of drainage-wide abundance for comparison with the mark-recapture estimate or other assessment methodology.
The primary objective of this project is to test methodologies for enumerating three select components of the Stikine River coho population, specifically the Iskut River, Chutine River, and Katete River stocks.
The Pacific Salmon Treaty agreement requires development of new abundance-based management regimes for Stikine River coho salmon. A central requirement of an abundance-based management program is the development of defensible abundance estimates; ideally stock specific abundance and run timing. Besides being of value as indices, reliable abundance estimates for specific stocks have the potential to be used to estimate drainage-wide abundance using a genetic stock identification (GSI) ratiobased approach, once a Stikine River coho salmon baseline has been established.
The enumeration of Stikine River Chinook salmon is a critical component of abundance based management mandated by the Pacific Salmon Treaty. A key element of the enumeration is ongoing mark-recapture estimation based on application of tags to returning Chinook and the recovery of these tags in inriver fisheries, at enumeration facilities, and on spawning grounds. Event I of the mark recapture is the application of tags through a scientific live capture drift net program near Kakwan Point, Alaska, on the Stikine River operated jointly by Alaska Department of Fish and Game (ADF&G), Fisheries and Oceans Canada (DFO), and the Tahltan First Nation (TFN). This project covers a majority of Chinook salmon migration into the lower Stikine River at Kakwan, and applies spaghetti tags to as many returning fish as possible through two crews drift netting a minimum of 4 wet hours per day each day. This proposal seeks funding to support the DFO/TFN drift crew for the duration of Event I. Tag recoveries from spawning grounds are critical components of the mark-recapture project and this proposal also seeks funding to support a week of post-spawn sample collection and tag recovery field work at the Verrett River, a Stikine River indicator stock.
Southeast Alaska (SEAK) and Canadian aggregate abundance-based management (AABM) fisheries harvest Chinook salmon originating from throughout Southeast Alaska, Canada, and the southern U.S. This diverse mixture of migrating stocks requires a comprehensive coastwide genetic baseline to accurately estimate the stock composition of harvests. The overall goal of this project is to use a phased approach to develop a coastwide Chinook salmon single nucleotide polymorphisms (SNPs) baseline to estimate the stock composition of harvests in SEAK and Canadian AABM fisheries.
The two biggest hurdles to assembling a coastwide Chinook salmon SNP baseline are: 1) no single agency has all of the baseline tissue or DNA samples necessary to adequately represent coastwide Chinook salmon production, and 2) different agencies do not all necessarily use the same SNP panels. To address these hurdles, we have worked with collaborators at the University of Washington (UW) to compile lists of SNP markers and populations screened by agency and university labs from Canada and the U.S.
TRT Fisheries conducts long term adult sockeye enumeration weirs at Kuthai and King Salmon Lakes. Due to shallow water at both lake outlets, and resulting bear activity, there was an interest in trying to improve the efficiency of moving fish thru these weirs. In 2018, the Deparment of Fisheries and Oceans (DFO) provided video and power systems for trial video enumeration. This appeared to work very well, however the equipment has to be returned for DFO use next year. Therefore, it is proposed that TRT Fisheries would purchase the necessary video and power equipment to continue weir enumeration in this manner. Such will facilitate improved passage while minimizing fish handling.
Northern coho stocks, including Skeena River coho, are harvested in commercial, recreational and Aboriginal fisheries in Canada and Alaska. Establishing robust stock assessment programs for coho is important for maintaining future coho fisheries.
By comparing the relative proportions of populations of known abundance with those that are not consistently enumerated, we can develop an escapement estimate for the aggregate stock. Furthermore, increasing the number of populations in the SNP baseline will increase genetic resolution for coho, and allow us to identify the populations of origin with higher precision for coho captured in mixed-stock fisheries in Canada and the U.S. When used in conjunction with an abundance estimate of a specific coho population within the Skeena River aggregate, an upgraded genetic baseline will improve estimates of exploitation rates in mixed-stock fisheries and therefore further support informed decisions by fisheries management.
The Tlell River salmon counting weir provides one of the very few reliable wild coho salmon escapement counts on the north coast of BC and for Haida Gwaii. The Tlell River adult coho spawner count is the primary indicator and absolute index of abundance for Graham Island Lowland coho. Haida Gwaii resides within the Department of Fisheries and Oceans (DFO) statistical areas 1 and 2 for which 227 separate coho spawning populations have been identified and aggregated into 3 conservation units. Graham Island Lowland coho are located on the northern portion of Haida Gwaii in closer proximity to the main commercial and recreational fishing areas. It consists of more than 27 coho streams that due to access, dark tannic waters, undercut banks, and vegetation are impossible to enumerate by any means other than the Tlell River adult weir.
The coho and pink salmon enumeration data contributes to a long time-series of salmon spawner abundance maintained by DFO for stock assessment and conservation purposes, including discussions at the Pacific Salmon Treaty negotiations and dialogue between commercial and recreational fishing sectors. This data also contributes to local resource management by the Haida Nation and information for BC Parks and the Haida Nation who co-manage the Tlall Conservancy and Heritage Site.
Decheeka Falls is located in the Tahltan River watershed in a location that both Chinook and sockeye migrate enroute to the upper Tahltan River and to Tahltan Lake, respective salmon species spawning locations. This natural site has been a known site of concern for salmon passage having attention from Alaska State fisheries staff and Canadian fisheries staff in the 1950’s and 1960’s. It is not completely recorded but apparently remedial work was attempted during this time including both salvage transport of salmon and remedial passage efforts. In recent years the site has become more of a concern again with expected sockeye salmon numbers not completely materializing at the Tahltan Lake weir upstream. This may be due to significantly below average Tahltan River flow levels recorded for at least the past four years. Observations of salmon leaping at the Falls and pooling below the area have been recorded from helicopter surveys in 2017 and 2018. It has been suggested for years that passage at the Falls is limited at particular flows with low flow conditions being the suggested limiting condition however this is not for certain due to the absence of surveys during a range of flows. These conditions would impact the most significant stock to migrate the Falls, Tahltan Lake sockeye salmon, particularly those annual runs that are late in migrating overall or more consistently the salmon at the latter end of the run period when water levels decline in August near the latter portion of the run.