Does Catch-and-Release Angling Alter the Behavior and Fate of Adult Atlantic Salmon During Upriver Migration?

Abstract

To reproduce, Atlantic Salmon Salmo salar return to freshwater rivers and migrate upriver to spawning areas. This migration is the basis for recreational fisheries, which for conservation reasons are increasingly characterized by catch-and-release angling. The effectiveness of catch and release for Atlantic Salmon conservation is contingent on the ability of individuals to recover from angling, resume migration, and reach spawning grounds at appropriate times. We monitored 27 caught and released Atlantic Salmon in River Gaula in 2013, a prominent and relatively pristine Norwegian river, by affixing external radio transmitters to them. Those fish were compared with a control group of 33 individuals caught and radio-tagged at sea in bag nets before river entry. Whereas none of the control fish died during the study period, there were three mortalities among the caught-and-released fish (11%; significant difference). All mortalities were qualitatively associated with poor angler care, emphasizing the responsibility of anglers in practicing effective catch and release of Atlantic Salmon. Both control and caught and released Atlantic Salmon spent similar time resting below and in transiting a large natural barrier to migration, an 80-m gorge. The angled and released Atlantic Salmon were distributed in similar locations throughout the river during the spawning season compared with control fish, but those caught and released later in the season appeared to migrate shorter total distances than control fish. Among the caught and released Atlantic Salmon, 17% were recaptured by anglers, which was similar to the rate of recapture of the control fish (21%). Ultimately, individual and population fitness was not likely to be significantly compromised as a result of catch and release because individuals were recorded in spawning areas at appropriate times. Catch and release can therefore be considered a tenable strategy for balancing the costs and benefits associated with the recreational fishery.

Received September 26, 2014; accepted December 16, 2014

ACKNOWLEDGMENTS

This research was financed by the Research Council of Norway, contract 216416/O10. Additional support was provided by the Norwegian Institute for Nature Research, Carleton University, the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canada Research Chairs Program, the Norwegian Seafood Federation, the Norwegian Environment Agency, The Ministry of Trade, Industry, and Fisheries, and the County Governor of Sør-Trøndelag. R. J. Lennox was additionally supported by an NSERC graduate scholarship. The authors thank A. Jørrestol, A. Foldvik, M. Rognli, D. Karlsen, T. Rognes, and R. Krogdahl for assisting with data analysis and collection. Anglers that volunteered Atlantic Salmon for this study are thanked for facilitating the research. R. J. Lennox is especially grateful to Matt Hayes and the Winsnes Family as well as the Winsnes Fly Fishing Lodge in Singsås.