Adult Chinook Salmon Behavior and Survival after Catch and Release from Purse-Seine Vessels in Johnstone Strait, British Columbia

Abstract

In British Columbia, chinook salmon Oncorhynchus tshawytscha are commonly taken in purse-seine fisheries directed at other salmon species, but the need to conserve chinook salmon may reduce the opportunities for such fisheries to operate. To test the feasibility of a nonretention fishery (i.e., release) for chinook salmon, we used ultrasonic telemetry to estimate the survival rates of chinook salmon caught and released from purse-seine vessels in Johnstone Strait, British Columbia. From 1990 to 1992, we tracked 47 fish for durations ranging from 2 h 1 min to 32 h 48 min (mean, 16 h 48 min). For the first 24 h after release, the survival rate for all years combined was estimated to be 77% with 95% binomial confidence limits of 62% and 87%. Mortality was positively associated with longer landing time. Chinook salmon that survived spent between 57–64% of the next 24 h at depths less than 50 m where they were vulnerable to recapture by commercial purse-seine gear.