Identifying the physiological and behavioral responsiveness to characterize the stress coping style in the large yellow croaker (Larimichthys crocea)

Abstract

Consistent variation in behavior and physiology has been well recognized when fish responds to challenges, as defined as proactive and reactive coping styles which enlightens a compromise between production and welfare in aquaculture. In the present study, behavioral and physiological responses after a 3 min net restraint were evaluated to predict stress-coping styles in the lager yellow croaker (Larimichthys crocea). The behavioral responses to open field, avoidance, and swimming capability were assessed, and resting plasma cortisol, CRH, IFN-α, and IgM levels were measured in the proactive and reactive individuals. Results indicate that the recovery latency is a candidate to characterize the coping style, as L. crocea recovering more quickly from 3 min net restraint also having significant lower plasma cortisol, suggesting a proactive coping style. And recovery latency showed consistency at an interval of 10 days. Furthermore, proactive L. crocea were more active in exploration, risk averse, and superior in swimming capability than the reactive fishes. The physiological responses, including plasma cortisol, CRH, and IFN-α, were observed without significant difference, while IgM in the proactive significantly exceeded the reactive individuals at 7 days after the restraint stress. Overall, the net restraint is a predictive tool to assess the varying stress responsiveness in L. crocea, which is the first step into exploiting the importance of ethology to improve the production and welfare in L. crocea aquaculture.