Is mass removal an efficient measure to regulate the north American catfish ameiurus melas outside of its native range?

Abstract

The black bullhead (Ameiurus melas) is a North American species that has successfully established populations throughout Europe. The main management policy to regulate its population in France is systematic mass removal by fishers, but the efficiency of this measure has not been evaluated. In the Grande Brière Motièrre marsh (northwest France), this species currently dominates the fish assemblage. We sampled this black bullhead population with trap nets and by electrofishing. The non-commercial fishery was also surveyed. Length-frequency distributions were significantly different between trapped individuals and those sampled by electrofishing, suggesting a size-selectivity of trap nets. Abundance of black bullhead was negatively correlated with the fishermen activity, measured at variable locations of the study site. The young-of-the-year/adult ratio was constant at each site, suggesting that black bullhead might not compensate for fishing mortality with increased recruitment. © 2006, Copyright Taylor & Francis Group, LLC.