Fishery Contribution and Spawning Escapement of Coho Salmon Reared in Net-Pens in Southern Puget Sound, Washington

Abstract

The marine fishery catch and subsequent spawning escapement of coho salmon Oncorhynchus kisutch reared in marine net-pens in southern Puget Sound, Washington, was evaluated during a 5-year tagging study. The objective of this study was to estimate catch in sport and commercial fisheries and the escapement of adults from the fishery to spawning grounds in local streams. Annual estimated recovery (estimated catch plus escapement) averaged 17.1%, which is similar to recovery rates of coho salmon released from other facilities at about the same time. The Puget Sound commercial net fishery benefited most from the program; there was little annual fluctuation in the commercial catch of the pen-reared coho salmon. The Puget Sound sport catch of net-pen coho salmon was about half that of the commercial fishery and displayed considerable annual variation. The pattern of annual variation suggested that, in some years, the pen-reared coho salmon migrated toward more northerly and oceanic waters. Approximately 0.2% of the released coho salmon survived to enter streams in the general vicinity of the net-pens. Because the area is managed on a hatchery-priority basis, and hatchery fish are commonly stocked, the addition of these fish to the spawning escapement may be viewed as an additional benefit. The results of this study led to a 10-fold increase in the size of the net-pen rearing and release program.