Interception of wild Salmon Lake coho salmon by hatchery supported fisheries

Description

A total of 4,692 pre-smolt coho salmon Oncorhynchus kisutch were tagged with coded wire tags (CWTs) at Salmon Lake during spring 1994, and interception of these tagged coho was monitored during fisheries conducted in 1995. The marked fraction for the 1994 outmigration (0.2581) was determined by inspecting adults returning to spawn in 1995. Contribution of Salmon Lake coho salmon to sport and commercial fisheries in 1995 was 1740 fish. CWTs were also placed on 4,509 coho smolt at nearby Medvejie Hatchery (marked fraction=1) to allow comparison of recovery pattern for the wild stock coho at Salmon Lake and the hatchery stock released from Medvejie Hatchery. Contribution by both releases of CWTd fish to the Sitka sport fisheries was similar (65 fish. However, CWTd Salmon Lake coho contributed 328 fish to the troll fishery while CWTd Medvejie coho contributed less than half as many (162), indicating that migratory patterns are significantly different and the hatchery stock may not be a good indicator of fate of the wild stock. Fisheries conducted by gillnet and seine in the Deep Inlet Terminal Harvest Area harvested a minimum of 157 wild stock Salmon Lake coho (123 by gillnetters and 34 by seiners). This additional fishing pressure on the wild stock of coho salmon at Salmon Lake further increased exploitation rate, which had more than doubled from 35% in 1985 to 72% in 1989.

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