Department of Ocean Sciences, University of California, Santa Cruz, California.
Southwest Fisheries Science Center, Santa Cruz, California.
Mol Ecol. 2019 Apr;28(7):1611-1623. doi: 10.1111/mec.15044. Epub 2019 Apr 13.
Marine species with pelagic larvae typically exhibit little population structure, suggesting long-distance dispersal and high gene flow. Directly quantifying dispersal of marine fishes is challenging but important, particularly for the design of marine protected areas (MPAs). Here, we studied kelp rockfish (Sebastes atrovirens) sampled along ~25 km of coastline in a boundary current-dominated ecosystem and used genetic parentage analysis to identify dispersal events and characterize them, because the distance between sedentary parents and their settled offspring is the lifetime dispersal distance. Large sample sizes and intensive sampling are critical for increasing the likelihood of detecting parent-offspring matches in such systems and we sampled more than 6,000 kelp rockfish and analysed them with a powerful set of 96 microhaplotype markers. We identified eight parent-offspring pairs with high confidence, including two juvenile fish that were born inside MPAs and dispersed to areas outside MPAs, and four fish born in MPAs that dispersed to nearby MPAs. Additionally, we identified 25 full-sibling pairs, which occurred throughout the sampling area and included all possible combinations of inferred dispersal trajectories. Intriguingly, these included two pairs of young-of-the-year siblings with one member each sampled in consecutive years. These sibling pairs suggest monogamy, either intentional or accidental, which has not been previously demonstrated in rockfishes. This study provides the first direct observation of larval dispersal events in a current-dominated ecosystem and direct evidence that larvae produced within MPAs are exported both to neighbouring MPAs and to proximate areas where harvest is allowed.
海洋浮游幼虫物种通常表现出很少的种群结构，表明存在长距离扩散和高基因流。直接量化海洋鱼类的扩散是具有挑战性的，但很重要，特别是对于海洋保护区（MPA）的设计。在这里，我们研究了在一个边界流主导的生态系统中沿着约 25 公里海岸线采样的海带岩鱼（Sebastes atrovirens），并使用遗传亲子分析来识别扩散事件并对其进行特征描述，因为静止父母与其定居后代之间的距离是其一生中的扩散距离。大样本量和密集采样对于增加在这些系统中检测到亲子匹配的可能性至关重要，我们采样了超过 6000 条海带岩鱼，并使用一组强大的 96 个微单倍型标记进行了分析。我们确定了 8 对亲子关系，其中包括 2 条在 MPA 内出生并扩散到 MPA 外的幼鱼，以及 4 条在 MPA 内出生并扩散到附近 MPA 的鱼。此外，我们还确定了 25 对全同胞对，它们分布在整个采样区域内，包括推断的扩散轨迹的所有可能组合。有趣的是，其中包括 2 对当年幼鱼，它们的一个成员在连续两年中被采样。这些兄弟姐妹对表明了单配制，无论是有意还是无意的，这在岩鱼中以前没有被证明过。这项研究提供了在边界流主导的生态系统中首次直接观察到幼虫扩散事件的证据，并且直接证明了在 MPA 内产生的幼虫既可以输出到附近的 MPA，也可以输出到允许捕捞的邻近区域。
