Guo Yongyao, Li Tong, Liu Li, Li Tiancai, Deng Longjun, Zhu Siyi, Zhong Shun, Wang Qingjie, Wang Dongjie, Luo Wei, Du Zongjun
College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
Yalong River Hydropower Development Co., Ltd., Chengdu, 610051, China.
J Therm Biol. 2025 Aug;132:104233. doi: 10.1016/j.jtherbio.2025.104233. Epub 2025 Aug 18.
This study assessed the thermal limits of Percocypris pingi, initially reared at 9.86 °C. Fish were short-term acclimated to 12 °C, 18 °C, and 24 °C for two weeks, and their CT and CT were determined. A separate group underwent long-term acclimation in outdoor conditions, where water temperatures averaged 2.66 °C higher than the species' natural habitat. In September, when temperatures reached 28.91 °C, their CT was re-evaluated. Behavioral indicators-swimming speed, shoal cohesion, and temperature preference-were used to support thermal tolerance assessments. Our findings indicate that P. pingi exhibits a narrow thermal tolerance range. Specifically, fish acclimated at 12 °C, 18 °C, 24 °C and long-term acclimation of 28.91 °C showed CT values of 33.11 °C, 34.26 °C, 34.55 °C and 35.01 °C. Although CT increases only slightly with higher acclimation temperatures, recovery after the CT measurement was significantly impaired in the group acclimated at 24 °C for a short term. Only 13.33 % of individuals recovered within 30 min compared to 100 % in other groups. Behavioral analyses showed stable swimming speeds near CT in the 18 °C and 24 °C groups, but heightened activity in the 12 °C group. Additionally, shoaling behavior became more dispersed during CT testing. Temperature preference tests indicated a consistent inclination toward cooler zones (12-18 °C), suggesting that P. pingi may actively seek thermal refuges in natural environments to mitigate thermal stress. Habitat temperatures (19.5-27.6 °C) remain below the species' thermal tolerance (>33 °C), according to WorldClim data. Our temperature and behavioral data provide a reliable assessment of thermal risks for P. pingi and offer guidance for its conservation under climate change.
本研究评估了最初在9.86°C水温下饲养的平鳍鳅鮀的热极限。将鱼短期驯化至12°C、18°C和24°C，为期两周，并测定其临界高温（CTmax）和临界低温（CTmin）。另一组在室外条件下进行长期驯化，室外水温平均比该物种的自然栖息地高2.66°C。在9月水温达到28.91°C时，重新评估其CTmax。使用行为指标——游泳速度、鱼群凝聚力和温度偏好——来辅助热耐受性评估。我们的研究结果表明，平鳍鳅鮀的热耐受范围较窄。具体而言，在12°C、18°C、24°C驯化的鱼以及在28.91°C长期驯化的鱼，其CTmax值分别为33.11°C、34.26°C、34.55°C和35.01°C。尽管随着驯化温度升高CTmax仅略有增加，但在24°C短期驯化的组中，CTmax测量后的恢复能力显著受损。与其他组100%的恢复率相比，该组在30分钟内只有13.33%的个体恢复。行为分析表明，18°C和24°C组在接近CTmax时游泳速度稳定，但12°C组活动增强。此外，在CTmax测试期间，聚群行为变得更加分散。温度偏好测试表明，平鳍鳅鮀始终倾向于较凉爽的区域（12 - 18°C），这表明平鳍鳅鮀可能在自然环境中积极寻找热避难所以减轻热应激。根据WorldClim数据，其栖息地温度（19.5 - 27.6°C）仍低于该物种的热耐受温度（>33°C）。我们的温度和行为数据为平鳍鳅鮀的热风险提供了可靠评估，并为其在气候变化下的保护提供了指导。
