Senior Theses 2006
Lauren Ann Yeager (2006). Habitat utilization by reef fishes in three shallow-water biotopes in Manzanillo, Costa Rica
Faculty Advisor: Dr. William Szelistowski
Identifying nursery areas used by reef fishes is important for fisheries management and for understanding fish community dynamics. Reef fish communities were surveyed using underwater visual censuses in 10m x 2m belt transects at three shallow water habitats (seagrass, mixed seagrass/coral rubble, and reef crest) in Manzanillo, Caribbean coast of Costa Rica. At each site, abundance, estimated length, and life stage for all fish species were recorded along with benthic composition, depth, and visibility. Distinct fish communities were found among habitat types with mixed seagrass/coral rubble and reef crest sites being the most similar and having the highest abundances, species richness, and Shannon-Weiner diversity. The percent cover of seagrass was the most important habitat variable explaining fish community composition, and habitats grouped distinctly by environmental variables. There was no difference in mean fish length among habitats, and all habitats supported greater abundances of juveniles than adults. Reef crest and mixed seagrass/coral rubble habitat had greatest densities of juveniles of reef species attractive to tourists while seagrass habitat had greatest densities of species valued locally for food. These results indicate that these three habitats function differently in their support of reef fishes. These findings have important implications for management and conservation, highlighting the special need to monitor and preserve all three of these habitats.