Abstract:  Habitat selection of coral-dwelling fish by the end of their pelagic stage can have a major effect on their survival and distribution in the reef. While many studies focused on habitat preference based on the coral characteristics such as identity, complexity and location, few studies have dealt with the preference of this stage and with the effect of “roommates” – other fish that already inhabit the corals. My study dealt with habitat selection of the coral-dwelling fish Dascyllus marginatus, a common species in the Red Sea. After settlement, the home range of this species is extremely limited, encompassing only one or a few adjacent corals; therefore the question of the “roommates” in the range who may compete for food and space or may provide security is critical. To assess D. marginatus habitat selection, I performed a series of settlement-choice experiments in aquaria: (1) With empty corals – to determine basic preference patterns, (2) With juveniles of the common species Chromis viridis that have similar ecological requirements and hence are potential competitors, (3) With adult conspecifics and adult heterospecifics. The experiments were executed with varying inter and intra-specific densities, as well as with computer simulations to test for visual effects of body patterns of different fish species on D. marginatus habitat selection. The results of the experiments were compared with distribution patterns observed in the reef. The study shows that D. marginatus habitat selection follows predictable, density-dependent patterns, albeit the pattern of the species distribution in the reef is seemingly generalist. When alone, their habitat preference can be explained by the Ideal Free Distribution (IFD) model. However, the basic preference is changed and modified by the presence of other fish in the corals with relation to their identity, life stage and density: presence of young C. viridis has a negative effect on D. marginatus habitat preference that can be explained by competition for food and space. Adult conspecifics and adult C. virids have a positive effect, as their presence may provide some safety from predation. The results of the computer simulations indicate that young D. marginatus have the ability to recognize and distinguish between body patterns of different fish species and may use this information while selecting their settlement site.

Biography:  Ben completed his Masters degree in Biology and Ecology at the Ben Gurion University and the Interuniversity Institute for Marine Sciences in Eilat, Israel. His thesis researched coral dwelling fish habitat selection in relation to corals characteristics and in response to other fish inhabiting the corals. This was followed by a study in the Northern Red Sea to examine how political boundaries and marine management regimes can influence coral reef status in neighboring countries. In recent years, Ben has worked as an environmental consultant for various large-scale infrastructure projects in Israel and in eco-tourism projects initiatives in Nepal and Central America. Ben is interested in conservation planning both in marine and terrestrial ecosystems and in ways to promote conservation by economic means and education.