As marine environments are influenced by global warming there is a need to thoroughly understand the relationship between physiological limits and temperature in fish. One quick screening method of a physiological thermal tipping point is the temperature at which maximum heart rate (ƒHmax) can no longer scale predictably with warming and is referred to as the Arrhenius break temperature (TAB). The use of this method has been successful for freshwater fish by using external electrodes to detect an electrocardiogram (ECG), however, the properties of this equipment pose challenges in salt water when evaluating marine fish. To overcome these challenges, this study aimed to explore the potential use of implantable heart rate loggers to quantify the TAB of Chrysoblephus laticeps, a marine Sparid, following the ECG method protocols where ƒHmax is monitored over an acute warming event and the TAB is subsequently identified using a piece-wise linear regression model. Of the nine experimental fish, only five (56%) returned accurate ƒHmax data. The TAB of successful trials was identified each time and ranged from 18.09 to 20.10 °C. This study therefore provides evidence that implantable heart rate loggers can estimate TAB of fish which can be applied to many marine species.

中文翻译：

---

使用内部心率记录器确定鱼的心脏断点

由于海洋环境受全球变暖的影响，因此有必要彻底了解鱼类的生理极限与温度之间的关系。生理热临界点的一种快速筛选方法是最大心率 (ƒHmax) 不再随变暖而变化的温度，称为阿伦尼乌斯断裂温度 (TAB)。这种方法通过使用外部电极检测心电图 (ECG) 已成功用于淡水鱼，但是，在评估海水鱼时，该设备的特性对盐水提出了挑战。为克服这些挑战，本研究旨在探索植入式心率记录器的潜在用途，以量化 Chrysoblephus laticeps（一种海洋鲷科动物）的 TAB，遵循 ECG 方法协议，其中在急性变暖事件中监测 ƒHmax，随后使用分段线性回归模型识别 TAB。在九条实验鱼中，只有五条 (56%) 返回了准确的 ƒHmax 数据。每次确定成功试验的 TAB，范围为 18.09 至 20.10 °C。因此，这项研究提供的证据表明，植入式心率记录器可以估计可应用于许多海洋物种的鱼类的 TAB。