Mark-recapture Studies of Taku River Adult Sockeye Salmon Stocks from 1998 to 2002
Mark-recapture Studies of Taku River Adult Sockeye Salmon Stocks from 1998 to 2002

Author: James Everett Andel

Publisher:

Published: 2004

Total Pages: 180

ISBN-13:

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Annual mark-recapture studies of adult Taku River sockeye salmon (Oncorhyncus nerka) stocks were conducted by the Alaska Department of Fish and Game, the Canadian Department of Fisheries and Oceans and the Taku River First Nation from 1998 to 2002. The objectives of the program were: to provide annual inseason estimates of the inriver abundance of sockeye salmon and to document biological characteristics (migratory timing, migratory rates and age, sex, and size composition) of Taku River sockeye stocks. Marked-to unmarked ratios of salmon harvested in the Canadian inriver gillnet fisheries were used to develop estimates of the inriver abundance of sockeye. During the years 1998 to 2002, an annual averageof 5,349 sockeye salmon were tagged in fish wheels located at Canyon Island, Alaska, of which an average of 1,080 (20.2%) sockeye were subsequently recovered in fisheries or on the spawning grounds.The annual post-season inriver runestimates of sockeye salmon past Canyon Island from 1998 to 2002 was estimated to be 91,548, 113,705, 115,693, 192,269, and 135,233, fish respectively. Annual inriver Canadian commercial, aboriginal and test fisheries combined harvested 19,038, 20,681, 27,942, 47,998, and 31,053 sockeye salmon during those same years (1998 to 2002). The resulting annual spawning escapement estimtes for Taku River sockeye salmon from 1998 to 2002 was 72,271, 95,562, 87,298, 144,071, 103,343, fish respectively.The migratory timing (mean dates and standard deviation of migration) and run timing of the sockeye salmon run was similar to the 15 year average. The Kuthai Lake sockeye salmon stocks dominated the early portion, the Little Trapper Lake the middle portion, and the Tatsamenie Lake and mainstem stocks the late portion of the Taku River sockeye salmon run. Pink fish wheel catches were strong in 1998 and 1999 but below average in 2000 to 2002. Chum salmon fish wheel catches for this 5-year period continued to exhibit the trend of low catches that began in the mid-1980's.

Spawning Abundance of Chinook Salmon in the Taku River in 2003
Spawning Abundance of Chinook Salmon in the Taku River in 2003

Author:

Publisher:

Published: 2006

Total Pages: 178

ISBN-13:

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A cooperative study involving the Department of Fisheries and Oceans Canada, the Alaska Department of Fish and Game, and the Taku River Tlingit First Nation was conducted to estimate the number of spawning Chinook salmon Oncorhynchus tshawytscha in the Taku River in 2003 with a mark-recapture experiment. Fish were captured at Canyon Island on the lower Taku River with fish wheels from May through August and were individually marked with back-sewn, solid-core spaghetti tags. All tagged fish were also batch marked with an opercle punch plus removal of the left axillary appendage. Sampling on the spawning grounds in tributaries was used to estimate the fraction of the population that had been marked. The estimated spawning abundance of small Chinook salmon ( 400 mm long; mid-eye to fork of tail) was 3,489 (SE = 1,052). Spawning abundance of medium-size Chinook salmon (401-659 mm) was estimated to be 16,780 (SE = 2,274). Finally, spawning abundance of large-size fish (= 660 mm) was estimated to be 36,435 (SE = 6,705), and the estimated total of all fish was 56,704 (SE = 7,158). The sum of the peak aerial survey counts of large spawning Chinook salmon conducted at five index tributaries of the Taku River was 16% of the mark-recapture estimate. Age 1.3 fish (1998 brood year) constituted an estimated 40% of the spawning population, followed by age 1.2 fish (1999 brood year), which constituted an estimated 29% of the population