Davis William T, Drymon J Marcus, Powers Sean P
Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, 08544, United States of America.
Department of Marine Sciences, University of South Alabama, LSCB Room 25, Mobile, Alabama, 36688, United States of America.
PLoS One. 2015 Dec 2;10(12):e0144051. doi: 10.1371/journal.pone.0144051. eCollection 2015.
Understanding the complex nature of direct and indirect species interactions is a critical precursor to successful resource management. In the northern Gulf of Mexico fisheries ecosystem, red snapper (Lutjanus campechanus) and vermilion snapper (Rhomboplites aurorubens) are two commercially harvested species within a larger reef fish complex. These two species share similar habitats and diets; however, little is known about how these species partition habitat and dietary resources. In this study we examined the extent of spatial and dietary overlap between red snapper and vermilion snapper, and experimentally compared their feeding behavior. Field data from multiple gear types demonstrates that red snapper and vermilion snapper frequently cohabited reefs in the northern Gulf of Mexico, and Pianka's niche overlap indices suggest significantly overlapping diets. Experimental manipulations show that red snapper are the dominant forager of the two species, as red snapper foraging alone ate more shrimp per fish than vermilion snapper in both the single species (p = 0.003) and mixed species (p = 0.02) treatments. In addition, red snapper ate significantly more shrimp per fish in the mixed species treatment than in the single species treatment (p = 0.04). Vermilion snapper shrimp consumption per fish did not differ significantly between mixed and single species treatments. Cumulatively, our results suggest that spatial and dietary overlap could lead to competition between red and vermilion snapper in the study area; however, conclusively determining the existence of such competition would require further research.
了解直接和间接物种相互作用的复杂本质是成功进行资源管理的关键前提。在墨西哥湾北部渔业生态系统中，红鲷（Lutjanus campechanus）和朱红笛鲷（Rhomboplites aurorubens）是较大礁鱼群落中的两种商业捕捞物种。这两个物种具有相似的栖息地和饮食；然而，对于这些物种如何划分栖息地和饮食资源却知之甚少。在本研究中，我们考察了红鲷和朱红笛鲷在空间和饮食上的重叠程度，并通过实验比较了它们的摄食行为。来自多种渔具类型的实地数据表明，红鲷和朱红笛鲷经常共同栖息在墨西哥湾北部的珊瑚礁中，并且 Pianka 的生态位重叠指数表明它们的饮食存在显著重叠。实验操作表明，红鲷是这两个物种中的主要觅食者，因为在单物种处理（p = 0.003）和混合物种处理（p = 0.02）中，单独觅食的红鲷每条鱼吃掉的虾都比朱红笛鲷多。此外，在混合物种处理中，红鲷每条鱼吃掉的虾显著多于单物种处理（p = 0.04）。在混合和单物种处理之间，朱红笛鲷每条鱼的虾消费量没有显著差异。总体而言，我们的结果表明，空间和饮食重叠可能导致研究区域内红鲷和朱红笛鲷之间的竞争；然而，要最终确定这种竞争的存在还需要进一步研究。
