Evaluation of stocked game fish in the Tanana Valley, 1996

Description

Estimation of reproduction of Arctic char Salvelinus alpinus in Harding Lake, population structure of rainbow trout Oncorhynchus mykiss in three lakes, evaluation of visual implant tags as marks, habitat use by Arctic char, and analysis of the cost effectiveness of the stocking program in the Tanana Valley are described here. No juvenile Arctic char were captured in Harding Lake during two weeks of sampling. The abundance of rainbow trout in Little Harding Lake was estimated at 2,950 (SE=443) of which 353 (SE=59) were 250mm. The abundance estimate for rainbow trout in Craig Lake was 429 (SE=29) of which 106 (SE=18) were 240 mm. For Coal Mine #5 Lake the rainbow trout abundance estimate was 67 (SE=9). The proportion of visual implant tags that were shed increased to slightly more than 50% about one year after stocking. A second group of fish had shed 11% their tags a few months after stocking. During summer ten Arctic char affixed with sonic depth tags were observed in water warmer than 12C on only one of 144 observations. As summer progressed Arctic char became more dispersed in the water column but still avoided near surface water warmer than 12C. None of the fishery management objectives for cost-per-angler-day or harvest rates were achieved for any location in 1995. The average cost-per-angler-day for the stocking program was $8.49. Arctic grayling Thymallus arcticus provided the best cost/benefit in 1995 for dollar spent ($1.18) in contrast to Arctic char which had the worst ($19.72).

Subjects

Series Statement

• Fishery data series -- no. 97-35.

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