Temperature is a key determinant that governs fish survival, reproduction, growth and metabolism. In freshwater ecosystems, anthropogenic influences have resulted in acute and prolonged temperature changes which lead to lethal and sub-lethal impacts on the biota that occupy these environments. We assessed the effects of temperature on somatic and otolith growth and development of three species of native Australian freshwater fish (silver perch Bidyanus bidyanus, trout cod Maccullochella macquariensis and golden perch Macquaria ambigua) to simulate how thermal pollution from the release of unseasonably cold water from thermally stratified dams in Australian freshwater ecosystems may impact fish at critical life-history stages. Fish (31 days post-hatch) were exposed to four temperature treatments (13, 16, 20, 24 °C) for 30 days. Low temperatures resulted in reduced somatic growth, with no growth observed in silver perch and golden perch held at 13 °C over 30 days. Somatic growth was highest at the upper temperature of 24 °C. Morphological assessment of fish size reiterated that low water temperatures resulted in reduced body size, particularly in terms of body width and head size. Low temperatures were associated with reduced otolith growth in all species, however a somatic-otolith size relationship was maintained for all species in measures of otolith weight, area, length and perimeter. The sub-lethal impacts observed in our study are likely to manifest at the population level through a reduced capacity of larvae and juveniles to avoid size-dependent predation, a narrower range of prey sources due to extended gape-limited feeding and, ultimately, poorer survival and recruitment.

中文翻译：

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次优温度对三种淡水鱼类幼体和幼体发育和耳石形态的影响：对河流冷水污染的影响

温度是决定鱼类生存、繁殖、生长和新陈代谢的关键决定因素。在淡水生态系统中，人为影响导致急剧和长期的温度变化，从而对占据这些环境的生物群造成致命和亚致命的影响。我们评估了温度对三种澳大利亚本土淡水鱼（银鲈 Bidyanus bidyanus、鳟鱼 Maccullochella macquariensis 和金鲈 Macquaria ambigua）的体细胞和耳石生长和发育的影响，以模拟从不合时宜的冷水中释放出的热污染。澳大利亚淡水生态系统中的热分层水坝可能会影响处于关键生命史阶段的鱼类。鱼（孵化后 31 天）接受四种温度处理（13、16、20、24 °C）30 天。低温导致体细胞生长减少，在 13 °C 下保持 30 天以上的银鲈和金鲈未观察到生长。体细胞生长在 24 °C 的高温下最高。鱼类尺寸的形态学评估重申，低水温导致体型减小，特别是在体宽和头部尺寸方面。低温与所有物种的耳石生长减少有关，但所有物种在耳石重量、面积、长度和周长的测量中都保持着体细胞-耳石大小关系。在我们的研究中观察到的亚致死影响可能会通过幼虫和幼鱼避免大小依赖性捕食的能力降低，由于扩大的张口限制进食而导致猎物来源范围变窄，从而在种群水平上表现出来，并最终，