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）的设立通常会引发保护区与捕捞区间的环境异质性。为明确保护区与捕捞区的环境差异对海洋扩散过程的影响，我们通过野外调查与遗传亲权分析，对栖息于不同管理区域（即1处海洋保护区与2处捕捞区）海葵宿主的两种海葵鱼——公子小丑鱼（Amphiprion frenatus）与粉红海葵鱼（A. perideraion）——的种群丰度与补充模式展开了研究。研究结果显示，相较于捕捞区，两种海葵鱼在保护区内每株海葵宿主的个体丰度均更低（样本量n=1525株海葵，显著性p=0.032）。亲权分析结果同样表明，保护区内每株海葵宿主所接收的补充个体中，源自捕捞区及研究区域外的个体数量均低于捕捞区内的海葵宿主（样本量n=1525株海葵，显著性p<0.017）。但每头雌性海葵鱼的自身补充繁殖量在保护区与捕捞区间并无显著差异（样本量n=384头雌性个体，显著性p=0.516）。由于研究区域周边的海流不太可能导致保护区内幼体定居强度下降，因此海洋环流并非造成上述丰度与补充模式的关键驱动因素。取而代之的是，保护区内更强的下行控制（top-down control）以及/或宿主海葵密度更低，或是造成该研究结果的潜在影响因素。本研究结果凸显了海洋环境异质性作为影响种群连通性的关键因素的重要性。