Evaluation of stocked game fish in the Tanana Valley, 1998

Description

We estimated the population abundance of rainbow trout Oncorhynchus mykiss in three lakes managed to provide trophy-size rainbow trout. The estimated abundance of rainbow trout in Little Harding Lake was 1,220 (SE=56) of which 72 (SE=10) were estimated > 350mm tip-of-snout to fork-of-tail (FL). The abundance estimate for rainbow trout in Craig Lake was 191 (SE=4) of which 4 (SE=2) were estimated > 350mm. The abundance estimate for rainbow trout in Coal Mine #5 Lake was 959 (SE=226) of which 36 (SE=12) were estimated > 350mm. We attempted to estimate the number of rainbow trout that emigrate from Piledriver Slough within one week of stocking. Of 1,000 fish stocked we captured only 25 unique fish. Twenty-three were captured within 24-h of stocking. We consider this loss to the fishery insignificant. Temperature was recorded in three lakes from June to September. None of the temperatures exceeded the upper maximum temperature for rainbow trout (25C). However, the upper optimum temperature for rainbow trout (18C) was exceeded in the entire water column in one lake for 30 days. The other two lakes had areas of refuge where the temperature did not exceed 18C. Other stocked species such as Arctic char Salvelinus alpinus probably would not survive in these and similar lakes if suitable refuge was not present during summer. By altering our stocking methods we can stock catchable (>100g) Arctic char in late summer after temperatures have fallen. These fish would be available from mid-August through mid-June. This is an acceptable stocking method for put and take fisheries that exist in our popular small lakes.

Subjects

Series Statement

• Fishery data series -- no. 99-21.

Links

• URL