Behavioral interactions such as dominance are critical components of animal social lives, competitive abilities, and resulting distribution patterns with coexisting species. Strong interference competition can drive habitat separation, but less is known of the role of interference if agonistic interactions are weak. While most theoretical models assume interference abilities to be constant in an environment, few consider that the extent of interference can vary by habitat and change model predictions. Using baited underwater cameras, we show a consistent dominance status between two sympatric reef sharks at an uninhabited Pacific atoll. Blacktip reef shark (Carcharhinus melanopterus) and gray reef shark (Carcharhinus amblyrhyncos) relative abundance showed an inverse relationship to each other but the strength of this relationship varied by habitat. Reef shark relative abundance declined more rapidly in the presence of heterospecifics on forereef habitats as opposed to backreefs. In all habitats, gray reef sharks were more likely to bite bait cages than blacktips when both species were present, and appeared to be the dominant species. Intraspecific interactions were also apparent, with individual willingness to bite bait decreasing as the number of conspecifics increased. Gray reef sharks may exert differential control over blacktip foraging success in different habitats. Habitat-specific behavioral interactions may partially explain patterns of spatial separation between competing species where interference is weak.

支配地位等行为互动是动物社会生活，竞争能力以及与其他物种共存的分布模式的重要组成部分。强烈的干扰竞争可以推动生境分离，但是如果激动性相互作用较弱，则对干扰的作用知之甚少。虽然大多数理论模型都假定干扰能力在环境中是恒定的，但很少有人认为干扰程度会随生境和模型预测的变化而变化。使用诱饵的水下摄像机，我们在一个无人居住的太平洋环礁显示了两个同伴礁鲨之间的一致优势地位。黑鳍礁鲨（Carcharhinus melanopterus）和灰礁鲨（Carcharhinus amblyrhyncos）相对丰度彼此呈反比关系，但这种关系的强度因生境而异。与前礁相比，在前礁生境中存在异种物种时，礁鲨相对丰度下降得更快。在所有生境中，当两种物种都存在时，灰礁鲨比黑鳍鲨更容易咬住饵笼，并且似乎是优势种。种内相互作用也很明显，随着同种异型数量的增加，个体咬诱饵的意愿降低。灰礁鲨可能会在不同生境中成功控制黑梢觅食。生境特定的行为相互作用可能部分解释了干扰较弱的竞争物种之间空间分隔的模式。