Ecology of arctic grayling in Becharof Lake tributaries

Abstract

I studied the grayling populations in 4 tributaries of Becharof Lake. The grayling in Ruth River, and Salmon, Featherly and Becharof Creeks appear to be independent populations, with high fidelity to specific streams. All populations overwintered in the lake and migrated into the streams when water temperatures reached about 2.5 C. These populations contained some of the largest grayling in the state; generally >50% of the population exceeding 6 years in age and had fork lengths >400 mm. Interstream movement rates were about 2%, but intrastream movement was higher (18%). Spring migration into the streams extended from May-July. This extended migration may have invalidated the assumption of a closed population, and resulted in higher than actual estimated abundance. Abundance ranged from a low of 33 grayling/Km in Featherly Creek to a high of 230 grayling/Km in Becharof Creek. Survival rates were similar in all streams.