The impact of climate variability on recruitment, life history, and physiology of sympatric pairs of ciscoes (Teleostei: Coregonus spp.) in lakes

最近，有人推测全球变暖趋势可能有利于春季产卵的鱼类，而不是秋季产卵的鱼类。其背后的机制被认为是鱼类孵化的不同时间和浮游动物作为小鱼食物的春季高峰，以及由于生命周期对温度敏感的适应而产生的可变招募。在这里，我们比较了一种在深湖中同域的一对西斯科的孵化时间和早期招募，其中一种在秋天产卵，另一种在春天产卵。在这个冰期后的湖泊中，物种形成和分化发生在过去的1万年里。这两个物种之间的生态、行为和生理差异（产卵时间除外）被认为很低。通过跟踪这两个物种的生长、摄食、分布和早期生命阶段的生理表现，我们想测试春季产卵的物种是否确实更好地适应全球变暖导致的预期的更早的破冰和更高的泉水温度。此外，通过检查沿海掠食性鱼类的胃内容物，估计了两种鱼类对鱼食性鱼类的捕食风险。在未来，我们还将分析这两个物种和潜在杂交品种对冷暖温度的生理适应性。

Recently, it has been speculated that global warming trends may favor year-class strengths of spring-spawning in opposition to autumn-spawning fish species. The mechanisms behind were assumed to be a differential timing of the hatching of fish and the spring peak of the zooplankton as food for the small fish, and a variable recruitment due to temperature-sensitive adaptations of the life cycle. Here, we compare the timing of hatch and early recruitment of a sympatric pair species of ciscoes in a deep lake whereby one species spawns in autumn, and the other in spring. In this postglacial lake, speciation and divergence have occurred during the last 10,000 years. The ecological, behavioural and physiological differences between both species (except for the spawning time) are assumed to be low. By following the growth, feeding, distribution and physiological performance of the early life stages of both species, we want to test whether the spring-spawning species is indeed better adapted to the anticipated earlier ice break and higher spring water temperatures due to global warming. Furthermore, the predation risk against piscivorous fish is estimated for both species by inspecting the stomach content of littoral predatory fish. In the future, the physiological adaptation of both species and potential hybrids to cold and warm temperatures shall be analysed in addition.