Does Fish Conditioning in Aquaculture Increase Survival Success in the Wild? A Case Study on a Cyprinid Fish

Many endangered fish species in the wild are artificially bred, and their populations strengthened by stocking of aquaculture-raised juveniles. Because from aquaculture generally not well prepared for challenging life wild, we tested whether training selected challenges could improve survival after stocking. We chose conditioning on predation pressure (by learning predator image northern pike Esox lucius using chemical cues visual stimuli), increased rearing water velocity 20 cm × s−1, direct exposure to predation. The juvenile cyprinid asp (Leuciscus aspius) was used as a model prey species. A total 7949 were reared four groups combination high flow, predation, control treatments (low no predation; 2018, 2149, 1929, 1856 individuals, respectively). Of these, 1800 individuals released into three ponds with pike, mortality rates monitored relation two months passive telemetry arrays. remaining 6149 aquaculture-reared directly large reservoir, while 1426 that survived pond experiment ended. Fish reservoir 2020 2021 boat electrofishing telemetry. effect detected conditions, but semi-natural treatment more likely survive than counterparts. In laboratory environment, responded an increase shoal cohesion swimming activity, which demonstrate ability detect cues. However, fluvial conditions did result critical speed. study suggests may be sufficient prepare exposing survival.