We assessed the relative abundance of reef fishes and ita relation with physical   parameters and habitat at four sites in Culebra Bay, a human disturbed arca in Gulf of   Papagayo, Costa Rica (eastem Pacific) from March to October 1997. Based on 64   visual counts, we recorded 75 species of 28 families of reef fishes. Four   pomacentrids, Iwo labrids and one haemulid comprised the top seven most abundant   species, ranked as foliows: Chromis agrilobata, Thalassoma lucasanum, Abudefduf   troschelii, Haemulon steindaclineri, Halichoeres dispilus, Stegastes acapulcoensis,   and Stegastesflavilazus. Densities of many of the species varied significantly with   variable site depth. Our resulta reflect higher Beta diversity than other studies,   altough only 22% of the species were found at alI the study sites. The type of   substrate, the complexity, and the exposure of the reef may have a strong influence en   the distribution of many of the species of reef fishes in the Gulf of Papagayo. Four   possible groups of fish species were observed suggesting that spatial pattems were   stronger iban seasonal trends. The shallowest site was characterized by   Ophioblennius steindachneri, Microspathodon bairdii, M dorsalis and Abudefduf   lroschelii. An intennediate site with a more heterogeneous substrate, was composed   by S. acapulcoensis, Canihigaster punc:atissima, H. nicholsi, H chierchiae, 7'.   lucasanum, Sufflamen yerres and Serranus psittacinus. A slightly deeper site than   the previous was represented by Ji dispilus, Johnrandallia nigrirostris,   Pomacanthus zonipectus, Holacanthus passer, and S. flavilatus. Finally the deepest   site habitat, had a distinctive assemblage composed by C. atrilobata, Chaetodon humeralis, Diodon holocanthus, H. steindachneri, and H. maculicauda. In terms of   trophic groups, our resulis shows trends have more affinities to ternperate regions   were planktívores and invertebrates feeders are the most abundant than herbivores.