Shallow-water hake (Merluccius capensis) is a valuable demersal resource distributed throughout the Benguela Current region, from southern Angola to eastern South Africa. Previous molecular work revealed distinct populations confined to the northern and southern Benguela sub-systems, with asymmetrical migratory patterns. Here, we re-evaluated the geographic position of the genetic break in shallow-water hake for two seasonal sampling events: summer (February - March) and winter (June – August) with the intention of exploring the hypothesis of seasonal migration patterns across the geo-political boundary between Namibia and South Africa. A total of 503 samples were obtained between northern Namibia and the Cape Peninsula, South Africa, and amplified for nine microsatellite markers. Results suggest the presence of small seasonal differences in population composition, with “northern” individuals occurring in the southern Benguela samples in both summer and winter (9% and 3.3% overall, respectively), but “southern” individuals only being found in samples from north of the Orange River collected during the winter (~5% overall). Seascape genetic analyses suggest that the two populations are isolated by environment and that depth and sea surface temperatures might be important drivers in shaping the observed patterns. These results refined the asymmetrical migration patterns previously reported and further suggest that shallow-water hake migration patterns appear to fluctuate moderately with the seasons. We recommend that future stock assessments should be used to evaluate the likely consequences of these migration patterns under various fishery management scenarios.

浅水无须鳕 ( Merluccius capensis )) 是一种宝贵的底层资源，分布在从安哥拉南部到南非东部的本格拉海流地区。以前的分子研究揭示了局限于北部和南部本格拉子系统的不同种群，具有不对称的迁徙模式。在这里，我们重新评估了两个季节性采样事件：夏季（2 月至 3 月）和冬季（6 月至 8 月）的浅水无须鳕遗传断裂的地理位置，旨在探索季节性迁移模式的假设。纳米比亚和南非之间的地缘政治边界。在纳米比亚北部和南非开普半岛之间共获得了 503 个样本，并针对 9 个微卫星标记进行了扩增。结果表明人口组成存在小的季节性差异，“北方”个体在夏季和冬季都出现在本格拉南部的样本中（分别为 9% 和 3.3%），但“南方”个体仅在冬季收集的奥兰治河以北的样本中发现（~5 ％ 全面的）。海景遗传分析表明，这两个种群被环境隔离，深度和海面温度可能是形成观察到的模式的重要驱动因素。这些结果改进了先前报道的不对称迁移模式，并进一步表明浅水无须鳕迁移模式似乎随季节适度波动。我们建议应使用未来的种群评估来评估这些迁移模式在各种渔业管理情景下的可能后果。