Influence of protogynous sex change on recovery of fish populations within marine protected areas
Influence of protogynous sex change on recovery of fish populations within marine protected areas
复制标题
先雌性变性对海洋保护区内鱼类种群恢复的影响
DOI：
10.1002/eap.2070
复制
发表时间：
2020
影响因子：
5
通讯作者：
White, J. W.
中科院分区：
文献类型：
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作者：
Easter, E. E.;Adreani, M. S.;Hamilton, S. L.;Steele, M. A.;Pang, S.;White, J. W.
海洋保护区（MPAs）越来越多地被用作全球范围内的保护工具。在许多情况下，它们是自适应管理的：监测目标物种的丰度，并将观察结果与基于模型的种群恢复轨迹预期进行比较，以确保MPA实现其目标。以前对海洋保护区内种群对停止捕捞的瞬时（短期）反应的大多数分析只涉及生殖器（固定性别）物种。然而，许多重要的渔业物种是雌雄同体（雌性到雄性的性别变化）。由于大小选择性收获将主要针对这些物种中的雄性，收获不仅减少了丰度，而且使性别比例偏向雌性。因此，对MPA实施的反应将涉及生存率和性别比例的变化，并最终涉及生殖产出。我们使用了一个年龄结构模型的通用性别改变鱼类种群比较MPA实施后的瞬时种群动态，否则类似的gonochore种群，并研究如何改变性别的生活史的不同功能影响这些动态。我们研究了人口统计学开放（大多数幼虫招聘来自MPA以外）和人口统计学封闭（大多数幼虫招聘是本地生产）的动态。在这两种情况下，当MPA之前的捕捞强度更大时（如生殖器），原始雌核物种的种群恢复需要更长的时间，但也在很大程度上取决于交配功能，即性别比例影响繁殖的程度。如果只需要很少的雄性，并且生殖不受高度女性偏见的性别比例的影响，那么人口恢复要快得多;如果雄性是一种有限的资源，那么MPA实施后丰度的增加要比生殖器慢得多。不幸的是，鱼类的交配功能在很大程度上是未知的。一般来说，我们预计大多数具有雌雄同体交配系统的雌性先熟物种将属于第一类（需要很少的雄性），尽管至少有一个鱼类物种（尽管不是变性物种）的雄性是限制性的。因此，需要更好地了解雄鱼的重要性，以适应性管理的海洋保护区的人口动态。
Marine protected areas (MPAs) are increasingly implemented as a conservation tool worldwide. In many cases, they are managed adaptively: the abundance of target species is monitored, and observations are compared to some model‐based expectation for the trajectory of population recovery to ensure that the MPA is achieving its goals. Most previous analyses of the transient (short‐term) response of populations to the cessation of fishing inside MPAs have dealt only with gonochore (fixed‐sex) species. However, many important fishery species are protogynous hermaphrodites (female‐to‐male sex‐changing). Because size‐selective harvest will predominantly target males in these species, harvesting not only reduces abundance but also skews the sex ratio toward females. Thus the response to MPA implementation will involve changes in both survival and sex ratio, and ultimately reproductive output. We used an age‐structured model of a generic sex‐changing fish population to compare transient population dynamics after MPA implementation to those of an otherwise similar gonochore population and examine how different features of sex‐changing life history affect those dynamics. We examined both demographically open (most larval recruitment comes from outside the MPA) and demographically closed (most larval recruitment is locally produced) dynamics. Under both scenarios, population recovery of protogynous species takes longer when fishing was more intense pre‐MPA (as in gonochores), but also depends heavily on the mating function, the degree to which the sex ratio affects reproduction. If few males are needed and reproduction is not affected by a highly female‐biased sex ratio, then population recovery is much faster; if males are a limiting resource, then increases in abundance after MPA implementation are much slower than for gonochores. Unfortunately, the mating function is largely unknown for fishes. In general, we expect that most protogynous species with haremic mating systems will be in the first category (few males needed), though there is at least one example of a fish species (though not a sex‐changing species) for which males are limiting. Thus a better understanding of the importance of male fish to population dynamics is needed for the adaptive management of MPAs.