Hooking Mortality of Bait-Caught Rainbow Trout in an Idaho Trout Stream and a Hatchery: Implications for Special-Regulation Management

摘要

Mortality of rainbow trout Oncorhynchus mykiss caught and released by anglers using number 8 worm-baited hooks was investigated during 1990-1991 at the Hagerman (Idaho) State Fish Hatchery and within a 2-km segment of Badger Creek, Idaho. Cutting theline on deep-hooked rainbow trout reduced postrelease mortality by 36% in the hatchery and 58% in the wild during observations of 60 and 29-34 d, respectively. Seventy-four percent of hatchery rainbow trout and 60% of wild rainbow trout that had been hooked deeply and released by cutting the line shed hooks during the same periods. There were no significant differences (P > 0.05) in condition factors among surviving control, light-hooked, and deep-hooked hatchery rainbow trout. Seventeen percent of 281wild rainbow trout on Badger Creek were hooked in the gills or esophagus. Overall, hooking mortality was estimated to be 16% for wild rainbow trout. No significant differences in the incidence of deep hooking were observed between small (<200 mm total length) and large (>=200 mm) wild rainbow trout (P > 0.05). The frequency of deep hooking was associated with the type of stream habitat where hooking occurred (P < 0.02) and was higher for catches on a "slack line" than a "tight line" (P < 0.001). These data suggest that stream locations where bait anglers actually catch fish and the general habitat characteristics of a stream could influence bait-related hooking mortality. Other factors that could influence the compatibility of bait fishing and special-regulation fisheries for salmonids include natural mortality rates, the degree of participation in such fisheries by bait anglers, and the proportion of bait anglers that cut the leader on deep-hooked fish prior to release. Depending on management goals, bait fishing may be compatible with special-regulation fisheries for salmonids in more situations than is commonly believed.