Abundance, size, habitat utilization, and intrastream movement of juvenile coho salmon in a small southeast Alaskan stream

Abstract

Aquatic habitat was measured, and juvenile coho salmon Oncorhynchus kisutch abundance and intrastream migrations were monitored in Kake Bake Creek, Alaska, between 1985 and 1986. Fry densities averaged 0.88, 0.33, and 0.11 fish/m2 during August, November, and March, respectively; parr densities averaged 0.15, 0.09, and 0.05 fish/m2, during August, November, and March, respectively. Fry were distributed evenly between riffle, glide, and pool habitat types during August, but not during November or March. Parr were distributed evenly in riffle and glide habitats during August, November and March. Stream areas containing pools and large woody debris tended to have higher coho densities; habitat was generally a significant predictor of juvenile abundance despite low R2 values. Fall immigrants totaled 1,434 coho, with 764 immigrating into beaver ponds. Fall immigrants were bright silver in color and several had sea-lice Calugus spp. attached near their anal fins. Between April 1 and June 2, 1986, 586 coho smolts emigrated from Kake Bake Creek; 172 had been fall immigrants.