Prior residence, aggression and territory acquisition in hatchery-reared and wild brown trout

• Published in: Journal of fish biology Vol. 55; no. 4; pp. 868 - 875
• Main Authors: DEVERILL, J. I, ADAMS, C. E, BEAN, C. W
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01.10.1999
• Subjects: Agnatha and pisces; Animal aquaculture; Animal ethology; Animal productions; Biological and medical sciences; Freshwater; Fundamental and applied biological sciences. Psychology; Pisciculture; Psychology. Psychoanalysis. Psychiatry; Salmo trutta; Vertebrata; Vertebrate aquaculture; Salmonidae; Farming animal; Artificial stream; Dominance; Wild animal; Hatchery; Freshwater environment; Vertebrata; Salmo trutta; Territorial behavior; Pisces; Intraspecific competition; Aquaculture; Aggressiveness
• ISSN: 0022-1112; 1095-8649
• DOI: 10.1006/jfbi.1999.1045

In an artificial stream environment, established wild brown trout initiated 44% of the mean aggressive acts whilst hatchery-reared trout initiated 34% and introduced wild trout initiated 22%. Established wild fish maintained home stations closer to a point source of feed than did both hatchery-reared and introduced wild conspecifics. Established wild fish were the only group to show a positive mean specific growth rate during the trials. Introduced wild fish showed a slightly negative mean specific growth rate, whilst introduced hatchery-reared fish exhibited a considerable negative mean specific growth rate. These results suggest that established wild brown trout in a semi-natural stream environment display a prior-resident effect over late introductions of hatchery-reared and wild conspecifics. Introduced hatchery-reared fish were more aggressive and exhibited a lower mean specific growth rate than simultaneously stocked wild fish, suggesting that excessive expenditure of energy for unnecessary aggression may contribute to the poor survival of hatchery-reared fish after they are stocked into streams.