Experimental Size‐Selective Harvesting Affects Behavioral Types of a Social Fish

Abstract

AbstractIn most fisheries, larger fish experience substantially higher mortality than smaller fish. Body length, life history, and behavioral traits are often correlated, such that fisheries‐induced changes in size or life history can also alter behavioral traits. However, empirical evidence regarding how size‐selective harvesting alters the evolution of behavioral traits in exploited stocks is scarce. We used experimental lines of Zebrafish Danio rerio that were exposed to positively size‐selective, negatively size‐selective, or random harvest over five generations. Our aim was to investigate whether simulated fishing changed the mean personality of the surviving females five generations after initial harvesting halted. We found that mean boldness, activity, and sociability were significantly altered relative to the randomly harvested control line. Harvest‐induced changes in individual‐level personality were only detected in the negatively size‐selected line. By contrast, we did not detect harvest‐induced evolution of personality in the positively size‐selected line. We conclude that size‐selective harvesting alters individual personality in this social fish.