Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, Melbourne, Florida, United States of America.
Department of Biological Sciences, Florida International University, Miami, Florida, United States of America.
PLoS One. 2020 Sep 28;15(9):e0239842. doi: 10.1371/journal.pone.0239842. eCollection 2020.
Quantitative assessments of the capacity of marine reserves to restore historical fish body-size distributions require extensive repeated sampling to map the phenotypic responses of target populations to protection. However, the "no take" status of marine reserves oftentimes precludes repeated sampling within their borders and, as a result, our current understanding of the capacity of marine reserves to restore historical body-size distributions remains almost entirely reliant on independent, static visual surveys. To overcome this challenge, we promote the application of a traditional fisheries tool known as a "back-calculation", which allows for the estimation of fish body lengths from otolith annuli distances. This practical application was pursued in this study, using data collected in five marine reserves and adjacent fished reefs in the Philippines, to investigate spatiotemporal disparities in length-at-age of the brown surgeonfish, Acanthurus nigrofuscus. The spatial component of our analyses revealed that 1) A. nigrofuscus were phenotypically similar between marine reserves and fished reefs during their early life history; 2) marine reserve and fished reef populations diverged into significantly different length-at-age morphs between ages three and six, in which protected fish were predominantly larger than conspecifics in fished reefs; and 3) A. nigrofuscus returned to a state of general phenotypic similarity during later life. The temporal component of our analyses revealed that younger generations of A. nigrofuscus exhibited significant, positive year effects that were maintained until age eight, indicating that, within the significant age cohorts, younger generations were significantly larger than older generations.
海洋保护区恢复历史鱼类体型分布的能力的定量评估需要广泛的重复采样，以绘制目标种群对保护的表型响应图。然而，海洋保护区的“无捕捞”状态通常禁止在其边界内进行重复采样，因此，我们对海洋保护区恢复历史体型分布能力的理解几乎完全依赖于独立的、静态的视觉调查。为了克服这一挑战，我们提倡应用一种称为“回溯”的传统渔业工具，该工具允许根据耳石环的距离来估计鱼类的体长。本研究采用了这一实用方法，利用在菲律宾五个海洋保护区和相邻的捕捞礁采集的数据，调查了黑星石斑鱼（Acanthurus nigrofuscus）体长的时空差异。我们的分析的空间部分显示：1）在早期生活史中，A. nigrofuscus 在海洋保护区和捕捞礁之间表现出表型相似；2）在 3 至 6 岁之间，海洋保护区和捕捞礁的种群分化为明显不同的体长形态，其中受保护的鱼类比捕捞礁中的同种鱼明显更大；3）A. nigrofuscus 在后期生活中又恢复到普遍相似的表型状态。我们的分析的时间部分显示，年轻一代的 A. nigrofuscus 表现出显著的正年效应，一直持续到 8 岁，这表明在显著的年龄群体中，年轻一代比老年一代明显更大。
