Boldness in fishes: A selection tool for aquaculture or a personality type with no apparent return?
2018
Skov, Peter V.
Behavioural and physiological results demonstrated that different emergence fractions of rainbow trout fry differed in certain characteristics. Early emerging fractions were more bold, they displayed more exploratory behaviour and recovered faster from startling compared to intermediate and late emerging fish. There were no differences in metabolic parameters of different emergence fractions, however, early emerging fractions had a smaller oxygen debt following chasing, and repaid it quicker. Early emerging fractions had a smaller cortisol response following a low water level challenge, but mobilization of glycogen stores did not differ between fractions. Early emerging fractions had a higher rate of weight loss in the face of starvation, probably linked to higher routine activity levels. The intermediate group was most starvation tolerant, and gained weight faster during refeeding. Co-habitation of different emerging fractions did not reveal a competitive advantage of early emerging fish under a restrictive feeding regime – again, the intermediate group outperformed the others. Overall, the intermediate group appears to have the best characteristics for production in an ‘optimal’ environment. Some fish farmers are currently using the early emerging fraction to put in sea cages. Though, the production costs are slightly higher, this is more than met and losses reduced!
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