Stock assessment of Arctic grayling in Piledriver Slough during 1996

Description

In 1996, a mark-recapture investigation was conducted to assess the stock of Arctic grayling Thymallus arcticus in Piledriver Slough, near Fairbanks, Alaska. The timing of the investigation corresponded with an exceptionally late spring breakup. A total of 808 Arctic grayling were captured with backpack electrofishing gear, marked, and released during late-May. During the late-June recapture sampling, 1,009 Arctic grayling were captured using the same methods and examined for marks, yielding 91 recaptures. An estimated 9,981 (SE = 1,256) Arctic grayling > 150 mm FL were present during late June. The 1996 stock was characterized by a high proportion of young Arctic grayling, and the age composition was predominated by age-3 fish. Significantly fewer Arctic grayling 270 mm FL were present in 1996 than at the last assessment in 1994. Densities of Arctic grayling have continued to remain at high levels (722 fish per km), but beaver dams have blocked migrations to headwater areas and reduced the total area of habitat by as much as 60%.

Subjects

Series Statement

• Fishery data series -- 97-18.
• Fishery data series -- no. 97-18.

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