PARENT SESSION
Poster Session 4: Marine Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Study of epifaunal colonization and community development using settlement panels in Veracruz reef system, Gulf of Mexico.

Diaz-Castañeda, Victoria^*,, de León, Angel,

ABSTRACT- Coral reefs are among the most complex and diverse biological communities. By providing substrata for sedentary organisms and food or shelter for mobile organisms, living corals create a rich series of habitats for a great diversity of species. The mechanisms through which benthic invertebrates respond to environmental perturbations are still relatively unknown. This work contributes to the knowledge of epibenthic colonization and particularly polychaete colonization patterns in VRS (Veracruz Reef System). The VRS is located at the western limit of the coral reef distribution in the Atlantic, which confers to it particular characteristics that make it different from other reef areas in the Caribbean biogeographic area. An experiment was designed to assess colonization patterns in three reefs subjected to different anthropogenic effects: Hornos, Pajaros and Blanca. Macrofauna colonization was studied analyzing 88 terracota panels. Panels (121 cm2) were attached in a vertical position, in areas dominated by live coral. Scuba was used for the attachment and removal. Individuals of ten phyla were collected: Bryozoa, Annelida, Arthropoda, Mollusca, Echinodermata, Sipuncula, Nemertea, Chordata, Cnidaria, Porifera. Polychaetes and peracarid crustaceans were the most abundant and diverse zoological groups. A total of 6,493 polychaete specimens belonging to 132 species was collected. The lag period (time of immersion which preceded macrofauna colonization) was of 3-4 days. The first colonizers were green filamentous algae, followed by red algae. Polychaetes, amphipods and young bivalves were the first to colonize in Pajaros and Blanca; in Hornos reef cirripeds and an unidentified species of ostracod were the first species to settle, followed by syllids and nereidids. Best represented families were Syllidae, Eunicidae, Nereididae, Cirratulidae, Terebellidae, Serpulidae and Sabellidae. MDS analysis revealed a separation of samples from each site. Polychaete communities established in each reef are not exactly the same, they differ in species composition and abundances although they share an important group of species. Results confirm the importance and colonizing success of polychaetes, especially syllids, serpulids and eunicids, in reef environments.

Key words: epibenthic colonization, polychaetes, Gulf of Mexico, coral reefs