Status of the Arctic grayling fishery in the upper Chatanika River during 1997

Description

In response to public concern, the status of the Arctic grayling Thymallus arcticus fishery in the upper Chatanika River was examined using a fishing survey through nearly all areas of river accessible to anglers driving the Steese Highway. The fishing survey consisted of a crew of three anglers with varied experience that conducted composition (age- and length) and CPUE sampling in 10 adjacent sections comprising the 72 km study area. Ages 4, 6 and 7 years predominated in the uncorrected sample. More than half of the fish caught (57%, N= 405 fish) had attained at least 12 inches TL (305 > mm TL), which is presently the minimum size for sport harvest. Catches in the upper sections of the study area included larger Arctic grayling, while greater numbers of small fish contributed to the catches in downstream sections. A total of 151 h of angling yielded a total catch of 423 Arctic grayling in the 10 days of sampling. While the overall CPUE estimate was 2.80 Arctic grayling per hour fished (SD = 1.39), CPUE varied in the 10 sections between 0.95 and 4.44 fish per hour. Additionally, CPUE was estimated in reference to Arctic grayling large enough for sport harvest. This estimate was 1.58 fish (SD = 0.77). For a subsample of 397 captures, an average of 19 min (SD = 23 min) angling was required to catch an Arctic grayling in the 72 km study area. Angling times ranged between 1 and 115 min. Higher catch rates and shorter angling times occurred in the middle and downstream sections which may relate to higher numbers of smaller Arctic grayling resident in those areas. The results of this study do not indicate a conservation concern exists for Arctic grayling in the upper Chatanika River. The variation in CPUE supports opinions of earlier researchers that productivity may be lower in the upper Chatanika River than in other nearby drainages.

Subjects

Series Statement

• Fishery data series -- no. 98-29.

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