Effects of catch-and-release angling on large cichlids in the subtropical Zambezi River

摘要

Long-term mortality and movements of cichlids after catch-and-release angling in a subtropical warm river were studied by radio tagging 15 nembwe (Serranochromis robustus) and 9 threespot tilapia (Oreochromis andersonii) in the Zambezi River in Africa. No direct mortality from catch- and-release angling was recorded, even though water temperatures were as high as 27-30 degreesC during capture. Indirect catch-and-release mortality could be increased risk of being predated upon before recovering from capture and release, as the transmitter from one threespot tilapia was found under a typical African fish eagle (Haliaeetus vocifer) tree, indicating that it was captured by a fish eagle. Excessive movements the first days after release compared to later in the season could indicate a behavioural reaction to capture and release. It is concluded that catch-and-release angling may be a successful management strategy to sustain recreational fisheries of cichlids in declining populations.