Injury and immediate mortality associated with recreational troll capture of bull trout ( Salvelinus confluentus) in a reservoir in the Kootenay-Rocky Mountain region of British Columbia

Abstract

We evaluated hooking injury and immediate mortality arising from capture of troll-caught adult bull trout ( Salvelinus confluentus) in a reservoir in the Kootenay-Rocky Mountain region of British Columbia in the spring (water temperature 2–15 °C) where regulations enabled anglers to use both barbed and barbless hooks. We captured 126 bull trout on lures and only a single mortality occurred (0.79% immediate mortality rate). Most bull trout maintained equilibrium and those that lost equilibrium were fought for significantly more time ( p = 0.03). Overall, approximately 79% of fish were hooked in the mouth. Nearly 16% of fish were foul hooked, which was independent of the number of hooks ( p = 0.76) and troll speed ( p = 0.08). Although not statistically related to troll speed, foul hooking occurred in nearly 90% of those captured at faster speeds (i.e., ≥5.3 kph). The depth that hooks swallowed was not influenced by trolling speed or the number of hooks ( p > 0.05 in all cases). Incidences of bleeding were lowest among single barbless hooks (10%) but did not significantly differ from the other hook configurations (∼18%). To our knowledge, this is the first study that examines such hook type issues in freshwater troll fisheries and the first published estimate of hooking mortality for bull trout, a species that is considered imperilled throughout much of its range. Although immediate mortality was very low, the high incidence of bleeding and foul hooking warrant further investigation into the impacts of different recreational fishing practices on short-term and delayed mortality of bull trout, especially for imperilled populations.