Survey of Coho Salmon Runs on the Pacific Coast of the Alaska Peninsula and Becharof National Wildlife Refuges, 1994 with Estimates of Escapement for Two Small Streams in 1995 and 1996

摘要

The primary objectives of this study were to describe the run timing and to evaluate methods for estimating escapement of coho salmon (Oncorhynchus kisutch) in small streams located on the Pacific side of the Alaska Peninsula. In the fall and winter 1994, aerial counts of adult coho salmon were conducted on several streams located along the Pacific Coast of the Alaska Peninsula and Becharof National Wildlife refuges. In 1995 and 1996, efforts were focused to estimate escapement of coho salmon on Clear and Sandy creeks. Escapement estimates were also generated opportunistically for pink (O. gorbuscha), chum (O. keta), and sockeye salmon (O. nerka). We assessed the applicability of using carcass counts to index escapement by exploring the relationship between escapement estimates and cumulative carcass counts between years and between streams. Live fish counts were extrapolated to estimate escapement using the area-under-the-curve method. Observer efficiency and species-specific residence times were measured on Clear Creek in 1996, and resulting averages were used in escapement calculations for Sandy Creek in 1995 and 1996, and for Clear Creek in 1995.