DOMINICA REEF FISH STATUS 2002: An Assessment of the Abundance and Species Composition of Dominican Reef Fishes. ITME

Reef fishes were surveyed at eight sites along the western coast of Dominica using a combination of two different roving diver techniques. The purpose of the study was to establish a list of marine fish species found in Dominican waters as well as to rank those species according to abundance. The top five species most abundant species, from highest to lowest, were Brown Chromis (Chromis multilineata), Bicolor Damselfish (Pomacentrus partitus), Ocean Surgeonfish (Acanthurus bahianus), Sergeant Major (Abudefduf saxatilis), and Yellow Goatfish (Mulloidichthys martinicus). The top five most abundant families, from highest to lowest, were Pomacentridae, Acanthuridae, Mullidae, Haemulidae, and Aulostomidae. Species richness was also estimated at each of the eight survey sites. Introduction Reef fishes, as predators or grazers, play an important role in the community dynamics of coral reefs through their interactions with corals, algae, and other herbivores (AGRRA 1999). Fluctuations in fish populations, especially certain indicator species and guilds cause both direct and indirect shifts in the structures of fish communities as well as other components of coral communities (Hughes 1994). Disruption in the balance of reef fish assemblages can also decrease coral cover and increase algal abundances (Roberts 1995). Because of this importance, fishes are often a focus of monitoring and management programs to evaluate the condition of reef communities (Hatcher et al. 1989). The purpose of this study was to establish some baseline data on the abundance and species richness of reef fishes along the west coast of Dominica, a relatively young volcanic island in the Lesser Antilles chain. Dominica’s underwater topography is characterized by a narrow, rocky, steeply sloping shelf upon which a variety of coral assemblages, and some true reef formations, are found. These coral communities attract a variety of fish species that are a mainstay of the local diet and economy. Thus, baseline data on Dominica’s reef fish populations can be useful for fisheries management decisions as well as future scientific studies. Materials and Methods Fish surveys were conducted at eight study sites along the west coast of Dominica during the months of October and November 2002. Listing from the northernmost to the southernmost, these sites were Tabby Bay, Salisbury West, Salisbury East, Macoucherie, Tarou Point, Canefield, Champagne, and Scott’s Head. Descriptions of each site can be found in the introduction of Smith et al (2002). A total of ten one-hour-long surveys were completed using both SCUBA and snorkeling equipment, with SCUBA being used at Salisbury East and Macoucherie and snorkeling at all others. Champagne and Macoucherie were both surveyed twice, while all other sites were only surveyed once. Surveys were carried out by utilizing two different roving diver techniques that were conducted simultaneously during each hour-long survey. The use of these two techniques resulted in two distinct measures of species abundance: timed scoring and visual scoring. During the surveys, species with visibly different life stages, such as some parrotfishes, wrasses, and angelifishes, were separated according to those stages. In addition, a separate