Growth and social interactions of wild and sea-ranched brown trout and their hybrids

• Published in: Journal of fish biology 2003-09, Vol.63 (3), p.673-686
• Main Authors: Petersson, E., Järvi, T.
• Format: Article
• Language: English
• Subjects: aggressiveness; Agnatha and pisces; Animal ethology; Animal, plant and microbial ecology; Applied ecology; behaviour; Biological and medical sciences; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); feeding rate; Fundamental and applied biological sciences. Psychology; growth rate; Psychology. Psychoanalysis. Psychiatry; Salmo trutta; Vertebrata
• ISSN: 0022-1112; 1095-8649
• DOI: 10.1046/j.1095-8649.2003.00180.x

A laboratory study of the social behaviour and growth performance of juvenile brown trout Salmo trutta of wild and sea‐ranched origin and their crosses, indicated that the social behaviour of wild and sea‐ranched fish differed. Male and female parents seemed to have a different impact on the juveniles. The category having wild mother and sea‐ranched father were less aggressive, less active in general, but active in feeding, and therefore had higher growth rates. This pattern arose despite that the feeding rate and the motivation to first get a food item when food was provided did not differ between the groups of fish. Wild fish tended to be most aggressive. If sea‐ranched and wild fish have different intrinsic (genetically based) ‘life styles’, the crosses between wild and sea‐ranched fish indicate that there is likelihood for an introgression of genes adapted to hatchery environment into the genetics of wild conspecifics. This is particularly serious when hatchery‐reared fish invades wild populations over many years.