By William Twardek, MSc. Candidate, Carleton University,
Little is known about the biological consequences of recreational fisheries for steelhead trout, despite steelhead being one of the most highly coveted species to anglers around the world. It is particularly important to account for the impact that recreational fisheries have on steelhead given that there are only a few wild populations left in the world distributed throughout the Pacific Northwest and Russia. In most, if not all recreational fisheries, anglers are required to release steelhead following capture under the premise that released fish suffer minimal fitness consequences. Although commercial fisheries for steelhead have indicated significant by-catch mortality of steelhead, few studies have evaluated the impacts of recreational angling on steelhead welfare.
Our study took place on the Bulkley River, British Columbia, that hosts one of the world’s most renowned steelhead recreational fisheries. Working with local fishing guides, we designed our study to accurately reflect the range of handling practices employed by anglers on the Bulkley River. We worked over 50 volunteer anglers to capture steelhead across a range of angling durations and water temperatures, and air exposure durations of either 0, 10, or 30 seconds. Our citizen science approach allowed our research to have a greater impact in the community and was essential for us given the expertise needed to successfully fly fish for steelhead. Anglers then helped us to either non-lethally blood sample steelhead to measure indices of metabolic stress or help us radio-tag steelhead to evaluate movement and survival following catch-and-release.
We located radio-tagged fish by mobile tracking over the next several months to evaluate delayed impacts of capture events on steelhead migration. Steelhead air exposed for just 10 and 30 seconds showed signs of immediate reflex and swimming impairment compared to those kept submerged under water after capture. Additionally, metabolic stress showed a positive correlation with water temperature at the time of capture. No components of the capture event were found to impact long-term migration rates, suggesting steelhead can likely recover shortly after capture. Overall, short (~95%), and long-term (85%) survival was high, indicating that catch-and-release angling can be implemented with high success for steelhead.
We will be presenting this work at the Pacific Salmon Marine Fisheries Commission – Steelhead meeting in Walla, Walla, Washington in March of 2018. We hope to inform fisheries managers throughout the Pacific Northwest about our mortality estimates, which they can then apply to existing data on catch rates to quantify the total number of steelhead that are lost to recreational fisheries each year. Further, we will be using the information generated in this study to distribute a set of best angling practice brochures to the tackle shops, hotels, lodges, and government offices within our study community so that anglers have a direct source to this information.