The endangered and range-restricted Maugean skate (Zearaja maugeana) is subjected to large environmental variability coupled with anthropogenic stressors in its endemic habitat, Macquarie Harbour, Tasmania. However, little is known about the basic biology/physiology of this skate, or how it may respond to future environmental challenges predicted from climate change and/or increases in human activities such as aquaculture. These skate live at a preferred depth of 5-15 m where the dissolved oxygen (DO) levels are moderate (~55% air saturation), but can be found in areas of the Harbour where DO can range from 100% saturation to anoxia. Given that the water at their preferred depth is already hypoxic, we sought to investigate their response to further decreases in DO that may arise from potential increases in anthropogenic stress. We measured oxygen consumption, haematological parameters, tissue-enzyme capacity and heat shock protein (HSP) levels in skate exposed to 55% dissolved O2 saturation (control) and 20% dissolved O2 saturation (hypoxic) for 48 h. We conclude that the Maugean skate appears to be an oxyconformer, with a decrease in the rate of O2 consumption with increasing hypoxia. Increases in blood glucose and lactate at 20% O2 suggest that skate are relying more on anaerobic metabolism to tolerate periods of very low oxygen. Despite these metabolic shifts, there was no difference in HSP70 levels between groups, suggesting this short-term exposure did not elicit a cellular stress response. The metabolic state of the skate suggests that low oxygen stress for longer periods of time (i.e. >48 h) may not be tolerable and could potentially result in loss of habitat or shifts in their preferred habitat. Given its endemic distribution and limited life-history information, it will be critical to understand its tolerance to environmental challenges to create robust conservation strategies.

中文翻译：

---

特有且濒临灭绝的毛金鳐鱼（Zearaja maugeana）表现出短期严重缺氧耐受性。


濒临灭绝且活动范围受限的毛吉亚鳐鱼（Zearaja maugeana）在塔斯马尼亚州麦格理港的特有栖息地，受到巨大的环境变化和人为压力的影响。然而，人们对这种鳐鱼的基本生物学/生理学，或者它如何应对气候变化和/或水产养殖等人类活动增加所预测的未来环境挑战知之甚少。这些鳐鱼喜欢生活在 5-15 m 的深度，那里的溶解氧 (DO) 水平适中（约 55% 空气饱和度），但也可以在 DO 范围从 100% 饱和度到缺氧的港口区域找到。鉴于它们喜欢的深度的水已经缺氧，我们试图研究它们对可能因人为压力的潜在增加而导致的溶解氧进一步减少的反应。我们测量了暴露于 55% 溶解氧饱和度（对照）和 20% 溶解氧饱和度（缺氧）48 小时的鳐鱼的耗氧量、血液学参数、组织酶容量和热休克蛋白 (HSP) 水平。我们得出的结论是，莫吉安鳐鱼似乎是一种氧构体，随着缺氧的增加，氧气消耗率降低。 20% O2 时血糖和乳酸的增加表明滑冰者更多地依赖无氧代谢来忍受极低氧的时期。尽管存在这些代谢变化，但各组之间的 HSP70 水平没有差异，这表明这种短期暴露不会引起细胞应激反应。鳐鱼的代谢状态表明，较长时间（即>48小时）的低氧应激可能是无法忍受的，并且可能导致栖息地的丧失或首选栖息地的改变。 鉴于其特有分布和有限的生活史信息，了解其对环境挑战的耐受性以制定强有力的保护策略至关重要。