Consequences of Fishery Gear Type and Handling Practices on Capture and Release of Wild Steelhead on the Bulkley River

Abstract

AbstractSteelhead Oncorhynchus mykiss are captured and released during spawning migrations by the commercial, subsistence (Indigenous), and recreational fishing sectors, though the consequences of these fisheries interactions on steelhead migration are poorly understood. This study evaluated injury, reflex impairment, behavior, and survival of released wild adult steelhead following capture in the subsistence dip‐net, subsistence beach‐seine, and recreational angling fisheries of the Bulkley River, British Columbia. Wild steelhead were captured using common handling practices employed in each fishery and were monitored postrelease using radiotelemetry. A greater proportion of steelhead captured by dip net and seine had impaired righting reflexes compared with angled fish, but only fish captured by dip net had notably higher incidence of injury (i.e., net marks, torn fins, flesh wounds, scale loss). Fish captured by dip and seine net had considerably faster peak migration rates (>4,000 m/d) than angled fish (<1,000 m/d), which likely reflects when the steelhead are encountered during their migration in these fisheries (earlier versus later stages). Air exposure (15–74 s) and water temperature (9.2–15.1°C) at the time of capture had significant negative relationships with 24‐h fallback behavior (temperature only), intermediate‐term (10–20 d after capture) migration rates, and peak migration rates in dip‐net‐captured steelhead. There were no significant effects of capture duration or fish length on injury, righting reflexes, or migratory behavior. Immediate mortality upon release was rare and occurred in only one fish captured by dip net. The 3‐d survival was 88–97% for dip‐net‐caught steelhead, 96–100% for seine‐caught steelhead, and 68–100% for angled steelhead. Despite inherent differences in timing and location between these fisheries, findings suggest that air exposure and water temperature can decrease steelhead migration rates. Fishers should look for opportunities to avoid or minimize these capture and handling conditions when releasing steelhead.