Differential responses of Nile tilapia (Oreochromis niloticus) to fin clip wounding and related stress: perspectives

The debate around fish welfare is intensifying in The Netherlands. As a result, more research is carried out to enhance knowledge on fish welfare in aquaculture. Detailed information is lacking on how production procedures causing discomfort to the fish may affect welfare. That fish must perceive adversive stimuli follows from the fact that nociceptive mechanisms similar to those in mammals are present in fish. However, whether and how nociceptive stimuli are perceived or interpreted by a fish is a far more difficult question that requires significantly more effort from fundamental research, both neurophysiological and behavioural studies, than now available. The study presented in this report aimed to define selected readout for the acute response to a supposedly painful stimulus: a standardised tailfin clip to a common carp. In conclusion, we succeeded to demonstrate differential, stronger responses to a presumed painful stimulus than to the handling stress per se associated with the administration of the pain stimulus. These parameters will be the focus of future research within this welfare project.