Environmental effects on behavioural development consequences for fitness of captive-reared fishes in the wild

• Published in: Journal of fish biology Vol. 85; no. 6; pp. 1946 - 1971
• Main Authors: Johnsson, J. I., Brockmark, S., Näslund, J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.2014; Wiley Subscription Services, Inc
• Subjects: Animals; Aquaculture - methods; Behavior, Animal; Behavioral Sciences Biology; Conservation of Natural Resources; density; Environment; Etologi; Fish and Aquacultural Science; Fisheries; Fishes - genetics; Fishes - physiology; Fisk- och akvakulturforskning; Genetic Fitness; hatchery; Phenotype; phenotypic variation; physical structure; reaction norm; salmonids; hatchery; reaction norm; salmonids; physical structure; density; phenotypic variation
• ISSN: 0022-1112; 1095-8649; 1095-8649
• DOI: 10.1111/jfb.12547

Why do captive‐reared fishes generally have lower fitness in natural environments than wild conspecifics, even when the hatchery fishes are derived from wild parents from the local population? A thorough understanding of this question is the key to design artificial rearing environments that optimize post‐release performance, as well as to recognize the limitations of what can be achieved by modifying hatchery rearing methods. Fishes are generally very plastic in their development and through gene–environment interactions, epigenetic and maternal effects their phenotypes will develop differently depending on their rearing environment. This suggests that there is scope for modifying conventional rearing environments to better prepare fishes for release into the wild. The complexity of the natural environment is impossible to mimic in full‐scale rearing facilities. So, in reality, the challenge is to identify key modifications of the artificial rearing environment that are practically and economically feasible and that efficiently promote development towards a more wild‐like phenotype. Do such key modifications really exist? Here, attempts to use physical enrichment and density reduction to improve the performance of hatchery fishes are discussed and evaluated. These manipulations show potential to increase the fitness of hatchery fishes released into natural environments, but the success is strongly dependent on adequately adapting methods to species and life stage‐specific conditions.