Does boldness explain vulnerability to angling in Eurasian perch Perca fluviatilis?

 Anssi Vainikka, Ilkka Tammela, Pekka Hyvärinen

Consistent individual differences (CIDs) in behaviour are of interest to both basic and applied research, because any selection acting on them could induce evolution of animal behaviour. It has been suggested that CIDs in the behaviour of fish might explain individual differences in vulnerability to fishing. If so, fishing could impose selection on fish behaviour. In this study, we assessed boldness-indicating behaviours of Eurasian perch (Perca fluviatilis) using individually conducted experiments measuring the time taken to explore a novel arena containing predator (burbot, Lota lota) cues. We studied if individual differences in boldness would explain vulnerability of individually tagged perch to experimental angling in outdoor ponds, or if fishing would impose selection on boldness-indicating behaviour. Perch expressed repeatable individual differences in boldness-indicating behaviour but the individual boldness-score (the first principal component) obtained using principal component analysis combining all the measured behavioural responses did not explain vulnerability to experimental angling. Instead, large body size appeared as the only statistically significant predictor of capture probability. Our results suggest that angling is selective for large size, but not always selective for high boldness