Division of Environment and Natural Resources, Norwegian Institute of Bioeconomy Research (NIBIO), Svanhovd, Norway.
Pasvik Strict Nature Reserve, 184424, Rajakoski, Murmansk Region, Russia.
Sci Rep. 2021 Aug 30;11(1):17396. doi: 10.1038/s41598-021-96681-1.
Maintaining standing genetic variation is a challenge in human-dominated landscapes. We used genetic (i.e., 16 short tandem repeats) and morphological (i.e., length and weight) measurements of 593 contemporary and historical brown trout (Salmo trutta) samples to study fine-scale and short-term impacts of different management practices. These had changed from traditional breeding practices, using the same broodstock for several years, to modern breeding practices, including annual broodstock replacement, in the transnational subarctic Pasvik River. Using population genetic structure analyses (i.e., Bayesian assignment tests, DAPCs, and PCAs), four historical genetic clusters (E2001A-D), likely representing family lineages resulting from different crosses, were found in zone E. These groups were characterized by consistently lower genetic diversity, higher within-group relatedness, lower effective population size, and significantly smaller body size than contemporary stocked (E2001E) and wild fish (E2001F). However, even current breeding practices are insufficient to prevent genetic diversity loss and morphological changes as demonstrated by on average smaller body sizes and recent genetic bottleneck signatures in the modern breeding stock compared to wild fish. Conservation management must evaluate breeding protocols for stocking programs and assess if these can preserve remaining natural genetic diversity and morphology in brown trout for long-term preservation of freshwater fauna.
维持人类主导景观中的遗传多样性是一个挑战。我们使用了 593 个当代和历史棕鳟（Salmo trutta）样本的遗传（即 16 个短串联重复）和形态（即长度和重量）测量值，研究了不同管理实践的微观和短期影响。这些管理实践已经从传统的繁殖实践（即多年使用相同的亲鱼）改变为现代的繁殖实践，包括在跨国的北极帕斯维克河（Pasvik River）中每年更换亲鱼。通过种群遗传结构分析（即贝叶斯分配测试、DAPC 和 PCA），在 E 区发现了四个历史遗传群（E2001A-D），可能代表了不同杂交产生的家族谱系。这些群体的特点是遗传多样性始终较低、群体内亲缘关系较高、有效种群规模较小，并且体型明显小于当代放养的（E2001E）和野生鱼类（E2001F）。然而，即使是当前的繁殖实践也不足以防止遗传多样性的丧失和形态变化，因为现代繁殖种群的平均体型较小，并且存在最近的遗传瓶颈迹象，与野生鱼类相比。保护管理必须评估放养计划的繁殖方案，并评估这些方案是否能够长期保护淡水动物区系中的剩余自然遗传多样性和形态。
