Data from: Individual variation in whole-animal hypoxia tolerance is associated with cardiac hypoxia tolerance in a marine teleost

Hypoxia is a pervasive problem in coastal environments and is predicted to have enduring impacts on aquatic ecosystems. Intraspecific variation in hypoxia tolerance is well documented in fish; however, the factors underlying this variation remain unknown. Here, we investigate the role of the heart in individual hypoxia tolerance of the European sea bass (Dicentrarchus labrax). We found individual whole-animal hypoxia tolerance is a stable trait in sea bass for more than 18 months (duration of study). We next examined in vitro cardiac performance and found myocardial muscle from hypoxia-tolerant individuals generated greater force, with higher rates of contraction and relaxation, than hypoxic-sensitive individuals during hypoxic exposure. Thus, whole-animal hypoxia tolerance is associated with cardiac hypoxia tolerance. As the occurrence of aquatic hypoxia is expected to increase in marine ecosystems, our experimental data suggest that cardiac performance may influence fish survival and distribution.

低氧（hypoxia）是沿海环境中普遍存在的问题，且预计会对水生生态系统造成持久影响。鱼类的低氧耐受种内差异已有充分的文献记载，但造成该差异的潜在因素仍未明确。本研究以欧洲海鲈（Dicentrarchus labrax）为研究对象，探讨心脏在其个体低氧耐受能力中的作用。研究发现，在超过18个月的实验周期内，欧洲海鲈的个体整体低氧耐受能力是一种稳定的性状。随后我们开展了体外心脏性能检测，结果显示：在低氧暴露过程中，相较于低氧敏感个体，低氧耐受个体的心肌可产生更强的收缩力，且收缩与舒张速率更高。综上，个体整体低氧耐受能力与心脏的低氧耐受能力密切相关。鉴于海洋生态系统中水生低氧事件的发生频率预计将持续上升，本实验数据表明，心脏功能或可影响鱼类的存活与分布。