Abstract Reproductive rates of copepods are temperature-dependent, but poorly known for small copepods at low temperatures, hindering the predictions of population dynamics and secondary production in high-latitude ecosystems. We investigated egg hatching rates, hatching success and egg production of the small copepods Oithona similis and Microsetella norvegica (sac spawners) and Microcalanus pusillus (broadcast spawner) between March and August. Incubations were performed at ecologically relevant temperatures between 1.3 and 13.2°C, and egg production rates were calculated. All egg hatching rates were positively correlated to temperature, although with large species-specific differences. At the lowest temperatures, M. pusillus eggs hatched within 4 days, whereas the eggs from sac spawners took 3–8 weeks to hatch. The egg hatching success was ≤25% for M. pusillus, >75% for O. similis and variable for M. norvegica. The maximum weight-specific egg production rate (μg C μg−1 C d−1) of M. pusillus was higher (0.22) than O. similis (0.12) and M. norvegica (0.06). M. norvegica reproduction peaked at 6–8°C, the prevailing in situ temperatures during its reproductive period. The difference in reproductive rates indicates species-specific thermal plasticity for the three copepods, which could have implications for present and future population dynamics of the species in arctic fjords.

中文翻译：

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小型携带卵和散播产卵桡足类 Oithona similis、Microsetella norvegica 和 Microcalanus pusillus 的温度依赖性产蛋率和卵孵化率

摘要 桡足类的繁殖率与温度有关，但对低温下的小型桡足类知之甚少，阻碍了对高纬度生态系统种群动态和二次生产的预测。我们调查了 3 月至 8 月间小型桡足类 Oithona similis 和 Microsetella norvegica（囊产卵动物）和 Microcalanus pusillus（广播产卵动物）的卵孵化率、孵化成功率和产蛋量。在 1.3 到 13.2°C 之间的生态相关温度下进行孵化，并计算产蛋率。尽管存在较大的物种特异性差异，但所有卵孵化率都与温度呈正相关。在最低温度下，M. pusillus 卵在 4 天内孵化，而来自囊状产卵器的卵需要 3-8 周才能孵化。M. pusillus 的卵孵化成功率 ≤ 25%，O. similis 的 >75% 和 M. norvegica 的可变性。M. pusillus 的最大重量特定产蛋率 (μg C μg-1 C d-1) 高于 (0.22) 比 O. similis (0.12) 和 M. norvegica (0.06)。M. norvegica 繁殖在 6-8°C 达到峰值，这是其繁殖期间的主要原位温度。繁殖率的差异表明三种桡足类具有物种特异性的热可塑性，这可能对北极峡湾物种当前和未来的种群动态产生影响。繁殖期的主要原地温度。繁殖率的差异表明三种桡足类具有物种特异性的热可塑性，这可能对北极峡湾物种当前和未来的种群动态产生影响。繁殖期的主要原地温度。繁殖率的差异表明三种桡足类具有物种特异性的热可塑性，这可能对北极峡湾物种当前和未来的种群动态产生影响。