In the last decade, there has been an increase in the study of the ecology of deep-sea organisms. One way to understand an organism's ecology is the study of its metabolism. According to literature, deep-sea sharks possess a lower anaerobic enzyme activity than their shallow-water counterparts, but no difference has been observed regarding their aerobic enzyme activities. These studies have suggested deep-sea sharks should be slow and listless swimmers. However, other studies based on video observations have revealed differences in cruise swimming speed between different species. The present study examined muscles of squaliform sharks, including both luminous and non-luminous species. We combined measurements of the relative amounts of red and white muscle with assays of enzymes that are used as markers for aerobic (citrate synthase, malate dehydrogenase) and anaerobic (lactate dehydrogenase) metabolism, searching for a relationship with cruising speeds. Non-luminous deep-sea species displayed lower aerobic enzymes activities but similar anaerobic enzymes activities than the benthic shallow-water counterpart (Squalus acanthias). Conversely, luminous Etmopteridae species were found to have similar aerobic enzymes activities to S. acanthias but displayed lower anaerobic enzymes activities. Analyses revealed that red muscle proportion and aerobic enzyme activities were positively related to the cruise swimming speed. In contrast, Dalatias licha, which swims at the slowest cruise swimming speed ever recorded, presented a very low aerobic metabolic phenotype (lower aerobic marker enzymes and less red muscle). Finally, the values obtained for white muscle proportion and anaerobic metabolic phenotype suggested a high burst capacity for D. licha and non-luminous sharks.

在过去十年中，对深海生物生态学的研究有所增加。了解生物体生态的一种方法是研究其新陈代谢。根据文献，深海鲨鱼的厌氧酶活性低于浅水鲨鱼，但它们的需氧酶活性没有差异。这些研究表明，深海鲨鱼应该是缓慢而无精打采的游泳者。然而，基于视频观察的其他研究揭示了不同物种之间巡航游泳速度的差异。本研究检查了鳞状鲨鱼的肌肉，包括发光和非发光物种。我们将红肌和白肌相对量的测量值与用作有氧运动标志物的酶（柠檬酸合酶、苹果酸脱氢酶）和厌氧（乳酸脱氢酶）代谢，寻找与巡航速度的关系。与底栖浅水物种相比，不发光的深海物种的需氧酶活性较低，但厌氧酶活性相似。Squalus acanthias )。相反，发现发光的 Etmopteridae 物种具有与S. acanthias相似的需氧酶活性，但显示出较低的厌氧酶活性。分析表明，红肌比例和有氧酶活性与巡航游泳速度呈正相关。相比之下，以有史以来最慢的巡航游泳速度游泳的Dalatias licha呈现出非常低的有氧代谢表型（较低的有氧标记酶和较少的红肌）。最后，获得的白肌比例和厌氧代谢表型的值表明D. licha和不发光的鲨鱼具有高爆发能力。