Studies have demonstrated adverse effects of global warming on aquatic ecosystems. However, the effects of increased water temperature (IWT) on fish reproduction are still doubtful in species spawning at low or high temperatures. In this meta‐analysis, we elucidated the effects of global warming on spermatozoa functions, key determinants of male fertility. We recruited 245 data records from 20 studies spanning 20 cold‐ and warm‐water fishes to identify the effects of IWT on sperm quality. Data were re‐processed and re‐analyzed to determine the overall effects of IWT on sperm kinetics such as percentage of motile spermatozoa (MOT), duration of spermatozoa motility (DSM), curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), as well as on enzymatic activities for energy supply (EAES) and antioxidant enzyme activity (ANEA). The standardized mean difference was calculated for each study, with positive values indicating higher performance under IWT. Results showed that (a) the overall effect size for MOT was larger negative in cold‐water fishes (−1.22) than in warm‐water fishes (−0.95). (b) Each 1°C increase in the activation medium reduced MOT by 1.30% (cold‐water fishes) and 3.47% (warm‐water fishes). (c) IWT negatively affected DSM, decreasing it by 10 s (cold‐water species) and 5.64 s (warm‐water species) per degree of IWT. (d) Spermatozoa velocity (VCL and VSL) increased by IWT in warm‐water species. (e) In cold‐water species, IWT‐induced detrimental effects on EAES were associated with adverse impacts on sperm motility kinetics. In conclusion, IWT negatively affects sperm motility kinetics, suggesting an impact of global warming on fish reproduction.

中文翻译：

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全球变暖对雄性鱼类质量的影响：温度对精子活力运动学影响的荟萃分析证据


研究表明全球变暖对水生生态系统产生不利影响。然而，在低温或高温下产卵的物种中，水温升高（IWT）对鱼类繁殖的影响仍然值得怀疑。在这项荟萃分析中，我们阐明了全球变暖对精子功能的影响，精子功能是男性生育能力的关键决定因素。我们从涉及 20 种冷水和温水鱼的 20 项研究中收集了 245 条数据记录，以确定内河运输对精子质量的影响。对数据进行重新处理和重新分析，以确定 IWT 对精子动力学的总体影响，例如活动精子百分比 (MOT)、精子活动持续时间 (DSM)、曲线速度 (VCL)、直线速度 (VSL)、平均路径速度（VAP），以及能量供应酶活性（EAES）和抗氧化酶活性（ANEA）。计算每项研究的标准化平均差异，正值表明内河运输中的表现较高。结果表明，(a) MOT 的总体效应大小在冷水鱼 (-1.22) 中比在温水鱼 (-0.95) 中更大。 (b) 活化介质每升高 1°C，MOT 就会减少 1.30%（冷水鱼）和 3.47%（温水鱼）。 (c) 内河运输对 DSM 产生负面影响，内河运输每度减少 10 秒（冷水物种）和 5.64 秒（温水物种）。 (d) 温水物种的精子速度（VCL 和 VSL）通过 IWT 增加。 (e) 在冷水物种中，IWT 引起的对 EAES 的有害影响与对精子运动动力学的不利影响有关。总之，内河运输对精子活力动力学产生负面影响，表明全球变暖对鱼类繁殖的影响。