Stability of behavioral syndromes but plasticity in individual behavior: consequences for rockfish stock enhancement

This study investigated behavioral syndromes, which are defined as correlations between behaviors. Behavioral syndromes can lead to the unintentional alteration of a wide range of behavioral traits of hatchery fish if unintentional selection on one behavior leads to selection on a correlated behavior. Specifically, this study used brown rockfish, Sebastes auriculatus, to test the hypothesis that a fish that feeds at high rates in the absence of a predator also takes more risks when a predator is present, and that through such a correlation, unintentional hatchery selection for high feeding rates may also lead to changes in risk taking behavior (here defined as behavior that increases predation risk). Behavioral syndromes were found-feeding behavior in the absence of a predator tended to correlate positively with both feeding behavior in the presence of a predator model and time near the model. These syndromes were stable through time-that is, the same correlations appeared 10 days later when the behavioral assays were repeated. However individual behavior was inconsistent (plastic). A fish could both feed and take risks at high rates on Day 1, but then both feed and take risks at low rates on Day 10. Thus, while behavioral syndromes were stable (i.e. present in both rounds 1 and 2), individuals were plastic in their behavior (i.e. inconsistent between rounds 1 and 2). After 16 weeks of hatchery rearing, neither growth nor survival were predicted by behavior. It is suggested that the behavioral plasticity within individuals through time makes consistent selection for strong feeders less likely, and that species with more plastic behavior may be less susceptible to unintentional selection on behavioral syndromes than species with behavior that is more fixed.