Fisheries Management of the European Catfish Silurus glanis Is Strongly Correlated to the Management of Non-Native Fish Species (Common Carp Cyprinus carpio, Rainbow Trout Oncorhynchus mykiss, and Grass Carp Ctenopharyngodon idella)

Abstract

Intensive multi-species fish stocking management is a popular yield enhancement tool that supposedly leads to elevated yields in recreational angling. This study aimed to analyze the relationships between fisheries management of an apex predator and its putative prey. The GAM (generalized additive model) was used to analyze the relationships between the yields and the stocking intensities of European catfish and non-native fish species. The fish yields and stocking intensities were obtained from mandatory angling logbooks collected from 38,000 individual recreational anglers by the Czech Fishing Union on 176 fishing sites during the years 2005–2017 in central Bohemia and Prague (the Czech Republic). Our results show that the stocking intensities of the targeted species positively correlated to their yields. However, intensive catfish stocking negatively correlated to the yields of the non-native fishes. Other factors that were strongly correlated to the yields include the angling effort, size of a fishery, and yield of catfish. In conclusion, a significant relationship is found between the fisheries management of a predator and its putative prey. The results suggest that catfish should not be intensively stocked in the same rivers as non-native fishes.