Department of Biological Sciences, Florida Institute of Technology, Melbourne, Florida, United States of America.
Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, Florida, United States of America.
PLoS One. 2018 Feb 22;13(2):e0193426. doi: 10.1371/journal.pone.0193426. eCollection 2018.
Human fishing effort is size-selective, preferentially removing the largest individuals from harvested stocks. Intensive, size-specific fishing mortality induces directional shifts in phenotypic frequencies towards the predominance of smaller and earlier-maturing individuals, which are among the primary causes of declining fish biomass. Fish that reproduce at smaller size and younger age produce fewer, smaller, and less viable larvae, severely reducing the reproductive capacity of harvested populations. Marine protected areas (MPAs) are extensively utilized in coral reefs for fisheries management, and are thought to mitigate the impacts of size-selective fishing mortality and supplement fished stocks through larval export. However, empirical evidence of disparities in fitness-relevant phenotypes between MPAs and adjacent fished reefs is necessary to validate this assertion. Here, we compare key life-history traits in three coral-reef fishes (Acanthurus nigrofuscus, Ctenochaetus striatus, and Parupeneus multifasciatus) between MPAs and fished reefs in the Philippines. Results of our analyses support previous hypotheses regarding the impacts of MPAs on phenotypic traits. Asymptotic length (Linf) and growth rates (K) differed between conspecifics in MPAs and fished reefs, with protected populations exhibiting phenotypes that are known to confer higher fecundity. Additionally, populations demonstrated increases in length at 50% maturity (L50) inside MPAs compared to adjacent areas, although age at 50% maturity (A50) did not appear to be impacted by MPA establishment. Shifts toward advantageous phenotypes were most common in the oldest and largest MPAs, but occurred in all of the MPAs examined. These results suggest that MPAs may provide protection against the impacts of size-selective harvest on life-history traits in coral-reef fishes.
人类捕捞活动具有大小选择性，优先捕捞收获种群中最大的个体。密集的、有针对性大小的捕捞死亡率会导致表型频率朝着较小和更早成熟个体的优势方向发生定向变化，这是鱼类生物量下降的主要原因之一。体型较小、年龄较小的鱼类繁殖产生的幼鱼数量较少、体型较小且生存能力较弱，严重降低了被捕捞种群的繁殖能力。海洋保护区（MPAs）在珊瑚礁中被广泛用于渔业管理，被认为可以减轻大小选择性捕捞死亡率的影响，并通过幼虫输出补充捕捞种群。然而，需要有实证证据来证明保护区和相邻捕捞礁之间在与适应度相关的表型方面存在差异，以验证这一说法。在这里，我们比较了菲律宾的三个珊瑚礁鱼类（Acanthurus nigrofuscus、Ctenochaetus striatus 和 Parupeneus multifasciatus）在保护区和捕捞礁之间的三个关键生活史特征。我们的分析结果支持了先前关于保护区对表型特征影响的假说。保护区和捕捞礁中的同种个体的渐近体长（Linf）和生长率（K）存在差异，受保护的种群表现出已知能提高繁殖力的表型特征。此外，与相邻区域相比，保护区内的个体达到 50%成熟时的体长（L50）有所增加，尽管 50%成熟时的年龄（A50）似乎不受 MPA 建立的影响。向有利表型的转变在最古老和最大的 MPA 中最为常见，但在所有受检的 MPA 中都发生了这种转变。这些结果表明，MPA 可能为珊瑚礁鱼类的生活史特征提供免受大小选择性捕捞影响的保护。
