Impacts of Recreational Angling on Fish Population Recovery after a Commercial Fishing Ban

Abstract

It is often assumed that recreational fishing has negligible influences on fish stocks compared to commercial fishing. However, for inland water bodies in densely populated areas, this assumption may not be supported. In this study, we demonstrate variable stock recovery rates among different fish species with similar life histories in a large productive inland freshwater ecosystem (Kaunas Reservoir, Lithuania), where previously intensive commercial fishing has been banned since 2013. We conducted over 900 surveys of recreational anglers from 2016 to 2021 to document recreational fishing catches and combined these catch estimates with drone and fishfinder device-based assessments of recreational fishing effort. Fish population recovery rates were assessed using a standardized catch-per-unit-effort time series in independent scientific surveys. We show that recreational fishing is slowing the recovery of predatory species, such as pikeperch Sander lucioperca (Linnaeus, 1758) and Eurasian perch Perca fluviatilis Linnaeus, 1758. The estimated annual recreational catches for these species were 19 tons (min-max of 7–55 tons) and 9 tons (4–28), respectively, which was considerably higher than the average commercial catch before the fishery closure (10 and 1 tons, respectively). In contrast, the recovery of roach Rutilus rutilus (Linnaeus, 1758), rarely caught by anglers (annual recreational catch of ca 3 tons compared to ca 100 tons of commercial catch), has been rapid, and the species is now dominating the ecosystem. Our study demonstrates that recreational fishing can have strong and selective impacts on fish species, reduce predator abundance, alter relative species composition and potentially change ecosystem state and dynamics.