Evolution of boldness and life history in response to selective harvesting

Abstract

20Whether intensive harvesting alters the behavioural repertoire of exploited fishes is currently unknown, but plausible. We extend a fish life-history model to account for 22 boldness as a personality trait that affects foraging intensity, which affects energy intake and risk from predation and fishing gear. We systematically investigate life-24 history and behavioral trait evolution along the boldness-timidity axis in response to the full range of common selectivity and exploitation patterns in fisheries. In agreement 26with previous studies we find that any type of harvesting selects for fast life histories and that merely elevated, yet unselective, fishing mortality favors boldness. We also 28 find that timid-selective fishing (which can be expected in selected species targeted by active gear types) selects for increased boldness. By contrast, increased timidity is 30 predicted when fishing targets bolder individuals common to passive gears, whether in combination with selection on size or not. Altered behavior caused by intensive 32 harvesting should be commonplace in nature, which can have far-reaching ecological, evolutionary and managerial impacts. Evolution of timidity is expected to strongly 34 erode catchability, which will negatively affect human well-being and influence the reliability of stock assessments that rely on fishery-dependent data. 36Key words: fisheries-induced evolution, timidity syndrome, personality traits, selection 38 gradients, life-history evolution Les modifications du comportement causés par la pêche intensive sont probablement 54 courants dans la nature, ce qui peut avoir d'importantes conséquences écologiques, évolutives et en termes de gestion. En particulier, l'évolution vers une plus grande 56 timidité peut éroder l'attrapabilité, affectant le bien-être des pêcheurs et la fiabilité des évaluations de stock reposant sur des données dépendantes de la pêche. 58

Size‐selective harvesting fosters adaptations in mating behaviour and reproductive allocation, affecting sexual selection in fish

“…higher number and proportion of fertilized eggs), independent of the other line that was involved in the spawning. These results can be interpreted as evidence for elevated reproductive fitness of the large‐harvested line, which represents the life‐history adaptation expected for exploitation contexts wherein large fish are selectively harvested (Andersen, Marty, & Arlinghaus, ; Jørgensen et al, ). Different fertilization rates in relation to personality and size have been previously documented in zebrafish (e.g.…”

Toward a mechanistic understanding of vulnerability to hook‐and‐line fishing: Boldness as the basic target of angling‐induced selection

“…For example, if there is a strong natural predation pressure on small‐bodied carp individuals, it is well possible that this creates large selection gradients toward large size that are greater than the negative selection gradients on growth rate documented here. If this is the case, the selection gradient on boldness should remain, and the evolution of timidity without a necessary change in growth is a possible outcome (Andersen et al., ; Arlinghaus et al., ). In fact, it is well possible that both fisheries and natural selection favors shyness in juvenile fishes (Ballew, Mittelbach, & Scribner, ).…”

“…Only species‐ and fishery‐specific models that account for the lifetime fitness of specific trait values and the correlations among traits can provide conclusive answers (Laugen et al., ). Before this research becomes available, depending on the species, fisheries‐induced selection of either fast, slow, or no change in juvenile growth rate can all happen (Dunlop, Heino, & Dieckmann, ; Enberg et al., ; Matsumura et al., ), but evolution of timidity is most likely if boldness increases the likelihood of capture (Andersen et al., ; Arlinghaus et al., ). We would thus predict that the most consistent response to intensive harvesting in response to passive gear is the evolution of timidity (Andersen et al., ; Arlinghaus et al., ).…”

Evolutionary effects of fishing gear on foraging behavior and life‐history traits

“…Applies to: The model by Andersen et al. (), which finds selection gradients on lifetime fitness one trait at the time…”

“…Applies to: Andersen et al. () (evolutionary transients) and the model and results in this paper (evolutionary endpoints)…”