Parental effects improve escape performance of juvenile reef fish in a high-CO2 world

Rising CO2 levels in the oceans are predicted to have serious consequences for many marine taxa. Recent studies suggest that non-genetic parental effects may reduce the impact of high CO2 on the growth, survival and routine metabolic rate of marine fishes, but whether the parental environment mitigates behavioural and sensory impairment associated with high CO2 remains unknown. Here, we tested the acute effects of elevated CO2 on the escape responses of juvenile fish and whether such effects were altered by exposure of parents to increased CO2 (transgenerational acclimation). Elevated CO2 negatively affected the reactivity and locomotor performance of juvenile fish, but parental exposure to high CO2 reduced the effects in some traits, indicating the potential for acclimation of behavioural impairment across generations. However, acclimation was not complete in some traits, and absent in others, suggesting that transgenerational acclimation does not completely compensate the effects of high CO2 on escape responses.

海洋中不断升高的二氧化碳（CO₂）水平预计将对众多海洋类群（marine taxa）造成严重危害。已有研究表明，非遗传亲本效应（non-genetic parental effects）可缓解高浓度CO₂对海洋鱼类生长、存活及日常代谢率（routine metabolic rate）的负面影响，但目前尚不明确亲本所处环境能否减轻高CO₂环境引发的行为与感官损伤。本研究针对高浓度CO₂对幼鱼（juvenile fish）逃逸反应（escape responses）的急性影响展开了测试，并探究了亲本暴露于高CO₂环境（跨代驯化，transgenerational acclimation）是否会改变此类效应。实验结果显示，高浓度CO₂会对幼鱼的反应活性与运动能力产生负面影响，而亲本经高CO₂暴露后，可在部分性状上削弱该负面影响，这提示跨代驯化具备缓解行为损伤的代际适应潜力。不过，部分性状的驯化效果并不完全，另有部分性状则未出现驯化效应，这表明跨代驯化无法完全抵消高浓度CO₂对鱼类逃逸反应的影响。