Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8528, Japan.
Hiroshima City Fisheries Promotion Center, Hiroshima, Hiroshima 733-0833, Japan.
J Therm Biol. 2021 Apr;97:102831. doi: 10.1016/j.jtherbio.2020.102831. Epub 2021 Jan 6.
Experienced thermal history often affects the temperature tolerance of fish; however, the effect of thermal history on growth performance is unclear. To contribute to effective stocking (release of hatchery-reared juveniles in the field), we conducted four laboratory experiments using juvenile marbled flounder (Pseudopleuronectes yokohamae, around 30 mm standard length and 0.3 g body wet weight) acclimated at 12 °C and 24 °C for approximately 2 weeks to investigate the effects of acclimation temperature on high-temperature tolerance, food consumption, and growth performance. The acclimation to 24 °C increased tolerance to high temperatures, as shown in a 24-h exposure experiment and in a temperature elevation experiment. The 50% lethal temperature (upper incipient lethal temperature) was estimated to be 25.9 °C and 29.0 °C for the 12 °C and 24 °C acclimation groups, respectively. In subsequent experiments, we tested the effects of high and low temperature acclimation on the food consumption and growth performance of two size groups of juveniles (28.7 ± 2.0 and 34.5 ± 2.9 mm, mean ± SD), that were reared at temperatures ranging from 14 °C to 23 °C. The optimal temperature for growth was 20 °C and did not differ between the acclimation temperatures or between the size groups. However, food consumption and growth performance were suppressed by acute temperature changes. Specifically, feeding and growth were lower in the 24 °C-acclimated group than in the 12 °C-acclimated group when exposed to 14 °C, which is close to the natural water temperature at release in the field. These results suggest that experienced thermal history does not affect the optimal temperature but can affect the growth performance of juveniles. To maximize the post-release growth of hatchery-reared juveniles, the influence of thermal history should be taken into consideration and acute thermal changes before release should be avoided.
经验性热历史通常会影响鱼类的温度耐受性；然而，热历史对生长性能的影响尚不清楚。为了有助于有效的放养（将养殖的幼鱼释放到野外），我们使用约 30 毫米标准长度和 0.3 克体重的幼鱼大理石斑（Pseudopleuronectes yokohamae）进行了四项实验室实验，这些幼鱼在 12°C 和 24°C 下适应了大约 2 周，以研究适应温度对高温耐受性、食物消耗和生长性能的影响。在 24°C 下适应会增加对高温的耐受性，如 24 小时暴露实验和温度升高实验所示。12°C 和 24°C 适应组的 50%致死温度（上初始致死温度）估计分别为 25.9°C 和 29.0°C。在随后的实验中，我们测试了高温和低温适应对两个大小组（28.7±2.0 和 34.5±2.9 毫米，平均值±标准差）幼鱼的食物消耗和生长性能的影响，这些幼鱼在 14°C 至 23°C 的温度下饲养。生长的最佳温度为 20°C，在适应温度或大小组之间没有差异。然而，急性温度变化会抑制食物消耗和生长性能。具体来说，在暴露于 14°C 时，24°C 适应组的摄食和生长低于 12°C 适应组，这接近于野外释放时的自然水温。这些结果表明，经验性热历史不会影响最佳温度，但会影响幼鱼的生长性能。为了最大限度地提高养殖幼鱼的放流后生长，应考虑热历史的影响，并避免放流前的急性热变化。
