title: Influence of harvest restrictions on angler release behaviour and size selection in a recreational fishery.
abstract: Fishing regulations such as harvest restrictions are implemented to limit the exploitation of many fish stocks and ensure the sustainability of fisheries. In Norway, inland recreational fisheries are co-managed by the government and by local riparian rights holders, meaning that Atlantic salmon Salmo salar harvest restrictions differ somewhat among rivers. Data from Norwegian rivers from 2009 to 2013 were used to test for variation in the proportion of salmon released by anglers and the relative size of salmon harvested and released by anglers in rivers that had varying harvest restrictions in terms of quotas, size restrictions, and/or female harvest restrictions. The proportion of the catch released by anglers was higher in rivers where there were harvest restrictions (proportion released = 0.09-0.24) than in rivers with no such restrictions (proportion released = 0.01). On average, salmon released in rivers with size restrictions larger (average mass difference between harvested and released salmon = -1.25 kg) than those released in rivers without harvest restrictions (difference = 0.60 kg). The proportion of the catch released was larger in rivers with seasonal quotas (0.29) than in rivers with daily (0.07) or collective (i.e. total catch for the river; 0.06) quotas. Rivers with low daily (one salmon per angler per day) or seasonal (<5 salmon per angler per year) quotas had a larger proportion of salmon released (0.23, 0.38, respectively) than rivers with moderate (0.10, 0.21) or high (0.07, 0.16) quotas. High seasonal quotas resulted in larger individuals harvested than released (difference = 1.16 kg), on average, compared to moderate (1.22 kg) and high seasonal quotas (-0.30 kg). We conclude that harvest restrictions influenced the extent to which fish were released and thus the stock composition (i.e. size distribution) escaping the recreational fishery with the potential to spawn.
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, Ontario K1S 5B6, Canada; Norwegian Institute for Nature Research, P. O. Box 5685, Sluppen, N-7485 Trondheim, Norway. Electronic address: robert.lennox@carleton.ca.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lennox
authors.affiliation: Norwegian Institute for Nature Research, Fram Centre, P. O. Box 6606, Langnes, N-9296 Tromsø, Norway.
authors.forename: Morten
authors.initials: M
authors.lastname: Falkegård
authors.affiliation: University of Oslo, Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, P.O.Box 1066, Blindern, N-0316 Oslo, Norway.
authors.forename: L Asbjørn
authors.initials: LA
authors.lastname: Vøllestad
authors.affiliation: Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, Ontario K1S 5B6, Canada.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Cooke
authors.affiliation: Norwegian Institute for Nature Research, P. O. Box 5685, Sluppen, N-7485 Trondheim, Norway.
authors.forename: Eva B
authors.initials: EB
authors.lastname: Thorstad
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D049628:Body Size; D003247:Conservation of Natural Resources / Q000331:legislation & jurisprudence*; D005260:Female; D005398:Fisheries; D009664:Norway; D011998:Recreation; D045483:Rivers; D020317:Salmo salar
keywords: Catch-and-release; Co-management; Fisheries induced evolution; Fisheries management; Salmo salar