Establishment of Sockeye (Oncorhynchus nerka) and Chinook (O. tshawytscha) Salmon Runs at Frazer Lake, Kodiak Island, Alaska

Abstract

Runs of sockeye salmon (Oncorhynchus nerka) and chinook salmon (O. tshawytscha) were established at Frazer Lake, Kodiak Island, Alaska by adult spawner transplants, fry plants, and eyed-egg plants. Falls in the lake outlet formed a barrier to natural ascent of anadromous fish until construction of a fishpass in 1962. Accounts of successful introduction and development of viable and self-sustaining runs of salmon where none previously existed and the lake was inaccessible are scarce in the history of salmon fisheries on the Pacific Coast. The first sockeye returning to Frazer Lake in 1956 were produced from egg plants in 1951. Annual sockeye returns have progressively increased over a 28-yr period reaching record passage of 141 981 in 1978. Sockeye spawning has extended into new areas as returns increased. Spawning area capacity is projected to be sufficient for 365 000 sockeye while rearing area is estimated to be sufficient to support fry production from 400 000 sockeye. Sockeye returns per spawner have averaged 3.2 for six parent years (1966–71) in which returns are complete. A chinook run was created from plants of 160 000 fry over a 4-yr period beginning in 1966. Chinook have returned to spawn in specific sites of fry release above the falls and in the lower river. Key words: salmon introduction, enhancement technique, sockeye, chinook, Frazer Lake, salmon establishment