Replication data for: Allochrony as a potential driver for reproductive isolation in adaptive radiations of European whitefish ecomorphs

The dataset contains biological, ecological and genetic data from European whitefish collected from 2 lake localities situated on the Finnmarksvidda highland plateau from 2016-2017. Fish sampling was carried out after standard protocols using multimesh gillnets in littoral, pelagic and profundal habitats. Parameters morphotype of whitefish, habitat, length, weight, sex, maturation and gonad weight. The prime focus is on reproductive isolation mechanisms.
In northern Fennoscandian lakes, monophylogenetic lineages of postglacial fishes are radiating into several adaptive forms, but the speciation process is still at an incipient stage. The speciation process has received increased attention over the years, but the underlying mechanisms and drivers are still debated and poorly understood. European whitefish (Coregonus lavaretus [L.]) is the most abundant fish species in these lakes and has evolved into several ecomorphs adapted to different trophic niches and habitats. Genetic divergence has been observed among these ecomorphs, but the mechanism(s) responsible for the ongoing build-up of reproductive isolation has still to be revealed. As these systems are young in evolutionary time (<10 kyr), pre- and post-zygotic extrinsic isolation mechanisms are thought to be more likely to contribute to the reproductive isolation than intrinsic isolation mechanisms. We determined the gonadosomatic index (GSI) of three ecomorphs in two replicated lake systems and used GSI as a proxy to investigate the pre-zygotic isolation mechanism, allochrony, as a driving factor of divergence in this adaptive radiation of whitefish. We found that the three ecomorphs differed in GSI-values within and between lakes, suggesting different spawning times of the ecomorphs. We also show that males of one ecomorph had equal onset of maturity as another ecomorph, giving novel insights into the ongoing gene flow observed between ecomorphs. The result supports allochrony as a driver for the divergence process of whitefish ecomorphs, but more evidence is still needed to rule out that the three ecomorphs make use of different spawning grounds.

该数据集收录了来自欧洲白鲑的生物、生态和遗传数据，这些数据采集自位于芬马克斯维达高原的两个湖泊区域，时间跨度为2016-2017年。鱼类样本的采集遵循标准流程，使用多网目鱼篓在沿岸、中层和底层生境中进行。数据包括白鲑的形态型、生境、长度、体重、性别、成熟度和卵巢重量等参数。研究的主要焦点在于繁殖隔离机制。在北欧斯堪的纳维亚湖泊中，冰川后鱼类单系谱系正在向多种适应性形态辐射，但物种形成过程仍处于初始阶段。近年来，物种形成过程受到了越来越多的关注，但其潜在机制和驱动力仍存在争议，理解不足。欧洲白鲑（Coregonus lavaretus [L.]）是这些湖泊中最丰富的鱼类物种，已进化出适应不同营养生态位和生境的多个生态形态。在这些生态形态之间观察到遗传分化，但导致持续繁殖隔离构建的机制尚待揭示。由于这些系统在进化时间上尚年轻（小于10千年前），因此认为在交配前和交配后的外源隔离机制比内源隔离机制更有可能对繁殖隔离作出贡献。我们确定了两个重复湖泊系统中三个生态形态的卵巢体指数（GSI），并利用GSI作为交配前隔离机制，即异时性，作为白鲑适应性辐射中分化过程的驱动因素的代理。我们发现，三个生态形态在湖泊内和湖泊间的GSI值存在差异，这表明生态形态的产卵时间不同。我们还展示了其中一个生态形态的雄性在成熟开始时间上与另一个生态形态相同，这为观察到的生态形态之间的持续基因流提供了新的见解。研究结果支持异时性作为白鲑生态形态分化过程的驱动因素，但仍需更多证据来排除三个生态形态使用不同产卵场的情况。