Review of social stress impacts on fish physiology, behavior, and immune function in aquaculture.

This narrative review examines the effects of social stress, specifically within dominance hierarchies and conflicts, on fish populations in aquaculture and research settings. The scope covers a range of secondary outcomes, including stress physiology, behavior, immune function, stress hormone release such as adrenaline and cortisol, pro-inflammatory cytokine activation, and depression-like or anxiety-like behaviors. The authors also discuss future performance and interactions between stress and the immune system.

The review indicates significant differences between dominant and subordinate individuals regarding stress physiology, behavior, and immune function. Additionally, varying levels of stress hormone release are observed between proactive and reactive individuals. The ability of the immune system to fight off pathogens is noted to be changed by stress hormones. In reactive individuals under stress, behavioral outcomes like sickness behavior result from feedback from pro-inflammatory cytokines. However, specific effect sizes, absolute numbers, and p-values were not reported for these findings.

The authors highlight the importance of strategies for reducing social stress in fish to enhance their overall health in aquaculture. They emphasize the need to consider these factors in research settings to prevent data bias. The review does not report specific adverse events, tolerability, or discontinuations. Limitations acknowledged by the authors regarding the certainty of the evidence or funding conflicts were not reported. Consequently, the practice relevance is framed cautiously, focusing on the qualitative synthesis of available data rather than definitive clinical guidelines.