Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
Temperate zone winters are experiencing greater rates of warming relative to other seasons and latitudinal regions globally. Spring-spawning fishes native to northern environments rely on both increasing temperature and lengthening photoperiod to cue reproduction and may thus be particularly sensitive to rapid warming earlier in the year while day lengths remain short. We investigated the reproductive response of pumpkinseed sunfish (Lepomis gibbosus) to spring warming commencing at a range of day lengths (9–15 hours), corresponding to various calendar days (10 January – 22 May). In both the laboratory and field, both male and female fish that experienced early warming while day lengths were <11 hours (1) failed to initiate reproductive preparation in the liver before gonad development began and (2) had reduced reproductive allocation. Analysis of published data on temperate fishes suggested that liver development prior to gonad development is widespread across warm-, cool-, and cold-water thermal guilds, though the precise phenology of liver relative to gonad development appears to vary widely among species. Together, our results point toward dampened reproductive preparation as a novel mechanism mediating reduced reproductive output in both warm- and cool-water fish following earlier spring warming.

中文翻译：

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春季变暖的时间决定了温水鱼的繁殖能力：肝脏和性腺过程不匹配的作用

加拿大渔业和水生科学杂志，印刷前。
相对于全球其他季节和纬度地区，温带冬季正在经历更大的变暖速度。原产于北方环境的春季产卵鱼依赖于温度升高和光周期延长来提示繁殖，因此可能对今年早些时候的快速变暖特别敏感，而白天的长度仍然很短。我们调查了南瓜籽翻车鱼 (Lepomis gibbosus) 对春季变暖的繁殖反应，这些反应在不同的日历日（1 月 10 日至 5 月 22 日）对应的一系列日长（9-15 小时）开始。在实验室和野外，雄性和雌性鱼在日长小于 11 小时时经历了早期变暖（1）未能在性腺发育开始之前在肝脏中启动生殖准备，（2）生殖分配减少。对已发表的温带鱼类数据的分析表明，性腺发育之前的肝脏发育在暖水、冷水和冷水热行会中普遍存在，尽管与性腺发育相关的肝脏的精确物候似乎在物种之间差异很大。总之，我们的研究结果表明抑制生殖准备是一种新的机制，在春季变暖后，温水和冷水鱼的生殖产量都会降低。