Dispersal and population-level mortality of Micropterus salmoides associated with catch and release tournament angling in a South African reservoir

This study assessed the impact of catch and release tournament angling on a largemouth bass (Micropterus salmoides) population in Wriggleswade Dam, a 1000 ha reservoir in South Africa. Effort was estimated at 648 boat days/year and catch as 2236 fish/year based on tournament catch data (2005–2012). Initial mortality rate (dead fish at the tournament weigh in) averaged 0.53%/yr. Dispersal was estimated from the recapture locations of 124 of 786 fish tagged and released during tournaments. The distance of the recapture locality from the release site (dispersal distance) was positively correlated with time at liberty for the first 50 days following release, after which recapture localities were random (average 4 km from the release site). At a population level, the instantaneous rate of total mortality (Z = 0.36–0.50 yr−1) was lower than in many other fisheries indicating a negligible impact of catch and release tournament angling at the effort levels experienced by this fishery.