Effects of two different habitats on Stegastes diencaeus (Longfin) damselfish population dynamics at Discovery Bay, Jamaica

The distribution of shallow water coral reef organisms is often a function of competition for limited resources (Connell, 1983). Coral reefs are intrinsically patchy, and the spatial distribution of benthic habitats can have important consequences for populations of motile site-attached species (Foster, 1987; Connell and Slatyer, 1977). An abundant herbivore on the shallow forereef community of Discovery Bay, Jamaica is the damselfish Stegastes diencaeus that is extremely territorially aggressive in behavior, with males defending algal gardens against conspecific and heterospecific competitors (Itzkowitz, 1977). Information regarding spawning and territorial behavior of S. diencaeus is limited, as are the distributions and potential interactions between this damselfish and different habitat types on Caribbean coral reefs. In the past, this damselfish species has been described as preferring habitat of sizeable (> 40 cm) rock and rubble on backreefs (Itzkowitz, 1977). The habitat of Discovery Bay has significantly changed since the 1970s, with coral communities now much less dominant on the forereef (Andres and Whitman, 1995) and S. diencaeus occupying a significantly large proportion of the forereef of Discovery Bay, Jamaica.It is the aim of this study to investigate the population of S. diencaeus within the narrow band of the shallow forereef of Discovery Bay, Jamaica, and how patterns of microhabitat on this narrow zone influence the distribution of this damselfish. Consequently, more detailed analysis of S. diencaeus populations dynamics such as total size and breeding behavior will be compared between two key habitats on the shallow Discovery Bay forereef.