Center for Ocean Observing Leadership, Department of Marine and Coastal Sciences, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ, United States of America.
College of Marine Science, University of South Florida, St. Petersburg, FL, United States of America.
PLoS One. 2019 Jun 13;14(6):e0218390. doi: 10.1371/journal.pone.0218390. eCollection 2019.
Over the last decade, ocean temperature on the U.S. Northeast Continental Shelf (U.S. NES) has warmed faster than the global average and is associated with observed distribution changes of the northern stock of black sea bass (Centropristis striata). Mechanistic models based on physiological responses to environmental conditions can improve future habitat suitability projections. We measured maximum, standard metabolic rate, and hypoxia tolerance (Scrit) of the northern adult black sea bass stock to assess performance across the known temperature range of the species. Two methods, chase and swim-flume, were employed to obtain maximum metabolic rate to examine whether the methods varied, and if so, the impact on absolute aerobic scope. A subset of individuals was held at 30°C for one month (30chronic°C) prior to experiments to test acclimation potential. Absolute aerobic scope (maximum-standard metabolic rate) reached a maximum of 367.21 mgO2 kg-1 hr-1 at 24.4°C while Scrit continued to increase in proportion to standard metabolic rate up to 30°C. The 30chronic°C group exhibited a significantly lower maximum metabolic rate and absolute aerobic scope in relation to the short-term acclimated group, but standard metabolic rate or Scrit were not affected. This suggests a decline in performance of oxygen demand processes (e.g. muscle contraction) beyond 24°C despite maintenance of oxygen supply. The Metabolic Index, calculated from Scrit as an estimate of potential aerobic scope, closely matched the measured factorial aerobic scope (maximum / standard metabolic rate) and declined with increasing temperature to a minimum below 3. This may represent a critical threshold value for the species. With temperatures on the U.S. NES projected to increase above 24°C in the next 80-years in the southern portion of the northern stock's range, it is likely black sea bass range will continue to shift poleward as the ocean continues to warm.
在过去的十年中，美国东北大陆架（美国 NES）的海洋温度比全球平均温度上升得更快，并且与黑鲈（Centropristis striata）北部种群的观察到的分布变化有关。基于对环境条件的生理反应的机械模型可以提高未来栖息地适宜性的预测。我们测量了北方成年黑鲈种群的最大、标准代谢率和缺氧耐受（Scrit），以评估该物种已知温度范围内的表现。采用两种方法，追逐和游泳槽，来获得最大代谢率，以检查两种方法是否存在差异，如果存在差异，对绝对有氧范围的影响。一部分个体在实验前在 30°C 下保持一个月（30chronic°C），以测试适应能力。在 24.4°C 时，绝对有氧范围（最大-标准代谢率）达到最大值 367.21 mgO2 kg-1 hr-1，而 Scrit 继续按比例增加到 30°C。与短期适应组相比，30chronic°C 组的最大代谢率和绝对有氧范围显著降低，但标准代谢率或 Scrit 不受影响。这表明尽管氧气供应得以维持，但在 24°C 以上，氧气需求过程（例如肌肉收缩）的性能下降。代谢指数，根据 Scrit 计算，作为潜在有氧范围的估计值，与实测的因子有氧范围（最大/标准代谢率）非常匹配，并随着温度的升高而下降到 3 以下的最小值。这可能代表该物种的一个临界阈值。随着美国 NES 的温度预计在未来 80 年内南部地区将上升到 24°C 以上，随着海洋继续变暖，黑鲈的范围很可能会继续向极地转移。
