Data from: Marine protected area restricts demographic connectivity: dissimilarity in a marine environment can function as a biological barrier

The establishment of marine protected areas (MPAs) can often lead to environmental differences between MPAs and fishing zones. To determine the effects on marine dispersal of environmental dissimilarity between an MPA and fishing zone, we examined the abundance and recruitment patterns of two anemonefishes (Amphiprion frenatus and A. perideraion) that inhabit sea anemones in different management zones (i.e., an MPA and two fishing zones) by performing a field survey and a genetic parentage analysis. We found lower levels of abundance per anemone in the MPA compared to the fishing zones for both species (n = 1,525 anemones, p = .032). The parentage analysis also showed that lower numbers of fishes were recruited from the fishing zones and outside of the study area into each anemone in the MPA than into each anemone in the fishing zones (n = 1,525 anemones, p < .017). However, the number of self-recruit production per female did not differ between the MPA and fishing zones (n = 384 females, p = .516). Because the ocean currents around the study site were unlikely to cause a lower settlement intensity of larvae in the MPA, the ocean circulation was not considered crucial to the observed abundance and recruitment patterns. Instead, stronger top-down control and/or a lower density of host anemones in the MPA were potential factors for such patterns. Our results highlight the importance of dissimilarity in a marine environment as a factor that affects connectivity.

海洋保护区（Marine Protected Areas, MPAs）的设立往往会导致其与捕捞区间产生环境差异。为明确海洋保护区与捕捞区间的环境差异对海洋扩散过程的影响，我们针对栖息于不同管理区域（即1处海洋保护区与2处捕捞区）的海葵宿主中的两种海葵鱼（Amphiprion frenatus与A. perideraion），通过野外调查与遗传亲权分析，探究其种群丰度与补充模式。研究发现，相较于捕捞区，两种海葵鱼在海洋保护区内的单海葵种群丰度均更低（样本量n=1525株海葵，p=0.032）。亲权分析结果同样显示，相较于捕捞区内的海葵，海洋保护区内的海葵所接收的、源自捕捞区及研究区外的补充个体数量更少（样本量n=1525株海葵，p<0.017）。不过，单雌性个体的自补充繁殖数量在海洋保护区与捕捞区间并无显著差异（样本量n=384尾雌性个体，p=0.516）。由于研究区域周边的海流不太可能导致海洋保护区内的幼体定居强度降低，因此海洋环流并非造成本次观测到的丰度与补充模式的关键因素。取而代之的是，海洋保护区内更强的下行控制作用，以及宿主海葵较低的种群密度，是形成上述观测结果的潜在因素。本研究结果凸显了海洋环境差异作为影响种群连通性因素的重要性。