Department of Biology, McGill University, Montreal, Canada.
Department of Biology, Carleton Univeristy, Ottawa, Canada.
J Fish Biol. 2020 Jul;97(1):231-245. doi: 10.1111/jfb.14355. Epub 2020 May 12.
We tested whether thermal tolerance and aerobic performance differed between two populations of Nile perch (Lates niloticus) originating from the same source population six decades after their introduction into two lakes in the Lake Victoria basin in East Africa. We used short-term acclimation of juvenile fish to a range of temperatures from ambient to +6°C, and performed critical thermal maximum (CT ) and respirometry tests to measure upper thermal tolerance, resting and maximum metabolic rates, and aerobic scope (AS). Across acclimation temperatures, Nile perch from the cooler lake (Lake Nabugabo, Uganda) tended to have lower thermal tolerance (i.e., CT ) and lower aerobic performance (i.e., AS) than Nile perch from the warmer waters of Lake Victoria (Bugonga region, Uganda). Effects of temperature acclimation were more pronounced in the Lake Victoria population, with the Lake Nabugabo fish showing less thermal plasticity in most metabolic traits. Our results suggest phenotypic divergence in thermal tolerance between these two introduced populations in a direction consistent with an adaptive response to local thermal regimes.
我们测试了来自东非维多利亚湖流域两个湖泊的两种尼罗鲈鱼（Lates niloticus）种群，在引入 60 年后，其热耐受能力和有氧性能是否存在差异。我们使用短期驯化幼年鱼的方法，将其置于从环境温度到+6°C 的一系列温度下，并进行临界热最大值（CT）和呼吸测量试验，以测量上限热耐受能力、休息时和最大代谢率以及有氧范围（AS）。在整个驯化温度范围内，来自较冷湖泊（乌干达纳布瓜博湖）的尼罗河鲈鱼的热耐受能力（即 CT）和有氧性能（即 AS）往往低于来自维多利亚湖温暖水域（乌干达布贡加地区）的尼罗河鲈鱼。温度驯化的影响在维多利亚湖种群中更为明显，纳布瓜博湖的鱼类在大多数代谢特征上表现出较低的热可塑性。我们的研究结果表明，这两个引入种群在热耐受能力方面存在表型差异，这与对当地热环境的适应性反应一致。
