Intraspecific variation in competitive ability and food intake in salmonids: consequences for energy budgets and growth rates

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Abstract

The interactions between dominance status, feeding rate and growth in rainbow trout, Salmo gairdneri Richardson, were analyzed using published data on experimental populations. There was a positive correlation between metabolic expenditure and food intake in both dominant and subordinate fish, but dominants obtained a greater intake for a given expenditure than did subordinates. Subordinates that adopted a high–return/high–cost foraging strategy actually expended more energy than they acquired, whereas those that minimized energy expenditure obtained a net energy gain. This led to the surprising finding that the growth rate of subordinates was negatively correlated with food intake.

Ancillary