Data of morphological and trophic divergence of lake and stream minnows (Phoxinus phoxinus)

I studied the divergence pattern of the European minnow (Phoxinus phoxinus), a common freshwater fish that has received little attention despite its large distribution. In many Scandinavian mountain lakes, European minnows are considered as being invasive and were found to pose threats to the native fish populations due to resource competition. Minnows were recently found to show phenotypic adaptations in lake versus stream habitats, but the question remained if this divergence pattern is related to differences in resource use. I therefore studied the patterns of minnow divergence in morphology (i.e., using geometric morphometrics) and trophic niches (i.e., using stomach content analyses) in the lake Ånnsjön and its tributaries to link the changes in body morphology to the feeding on specific resources.

In August 2018, minnows were caught from three lake locations (L1, L2, L3; Figure 1) using gill nets (1 × 10 m with 6 mm mesh size), which were exposed for up to 12 hr. Furthermore, minnows were collected from three different slow-flowing tributaries that were less than two km away from the lake: downstream Stor Klockbäcken (location S1), downstream Sjöviksbäcken (location S2), and downstream Kvarnbäcken (location S3) (Figure 1). In the streams, minnows were caught using an electrofishing approach and killed with an overdose of benzocaine. Fish were frozen to −20°C and transported to the laboratory at Uppsala University.

In total, 279 minnows were analyzed, 158 from the lake locations (L1: 52, L2: 52, L3: 54), and 121 in the streams (S1: 50, S2: 50, S3:21). In the laboratory, fish were thawed and subsequently individual length (to the nearest mm) was taken.

See Morphological and trophic divergence of lake and stream minnows (Phoxinus phoxinus) by Scharnweber (2020) for furhter methodological information.

The dataset was originally published in DiVA and moved to SND in 2024.

本研究针对欧洲鲦鱼（European minnow，*Phoxinus phoxinus*）的分化模式展开探究。该物种为分布广泛的常见淡水鱼类，却长期未受到学界足够关注。在众多斯堪的纳维亚山地湖泊中，欧洲鲦鱼被视为入侵物种，且因资源竞争对本土鱼类种群构成威胁。近期研究发现，欧洲鲦鱼在湖泊与溪流生境中已表现出表型适应性，但学界仍未明确这种分化模式是否与资源利用差异相关。为此，本研究以安恩湖（Ånnsjön）及其支流中的欧洲鲦鱼为研究对象，采用几何形态测量法（geometric morphometrics）与胃含物分析（stomach content analyses）分别探究其形态与营养生态位（trophic niches）分化模式，以期将身体形态变化与特定资源摄食行为建立关联。

2018年8月，研究人员使用刺网（规格为1×10 m，网目尺寸6 mm）在3个湖泊采样点（L1、L2、L3，见图1）采集欧洲鲦鱼样本，刺网布设时长最长达12小时。此外，研究人员在距离湖泊不足2公里的3条缓流支流中采集样本：分别为斯托尔·克洛巴克溪下游（采样点S1）、舍维克溪下游（采样点S2）以及克凡巴克溪下游（采样点S3），采样点位分布见图1。在溪流采样中，采用电捕鱼法捕获欧洲鲦鱼，随后使用过量苯佐卡因将其安乐死。样本经冷冻至-20℃后，运至乌普萨拉大学实验室进行后续处理。

本研究共分析279尾欧洲鲦鱼样本，其中湖泊采样点共158尾（L1：52尾，L2：52尾，L3：54尾），溪流采样点共121尾（S1：50尾，S2：50尾，S3：21尾）。在实验室中，研究人员先将样本解冻，随后测量每尾鱼的体长（精确至1 mm）。

详细实验方法可参考Scharnweber（2020）发表的《湖泊与溪流欧洲鲦鱼的形态与营养分化》一文。

本数据集最初发布于DiVA平台，并于2024年迁移至SND平台。