Implications of domestication and rearing conditions for the behaviour of cultivated fishes

Farmed fishes are often selectively bred for desirable production traits, such as rapid growth, that brings with them behavioural differences. In addition, the striking differences in the environment experienced by wild and cultured fishes offers considerable scope both for unplanned, natural selection for different inherited behavioural phenotypes and for behavioural differences arising from differential experience. In this paper, the evidence that such processes have produced behavioural differences between wild and cultured fishes is reviewed in relation to feeding, antipredator responses, aggression and reproductive behaviour. The reported findings are discussed in relation to the concept of 'behavioural syndromes', or suites of co-varying behavioural traits that adapt individuals of the same population to spatial and temporal variation in selection regimes. The implications of the behaviour of cultured fishes for their welfare in production cages, for the environmental impact of escapees on wild stocks and for the success of hatchery-based restocking programmes are considered. The review inevitably concentrates on salmonids, in which such phenomena have been intensively researched. (C) 2004 The Fisheries Society of the British Isles.