Ramirez, J. T.. University of Puerto Rico, Mareja@aol.com
Garcia, J. T.. University of Puerto Rico, email@example.com
SPATIAL DISTRIBUTION AND TAXONOMIC STRUCTURE OF LARVAL REEF FISHES ACROSS A NERITIC-OCEANIC GRADIENT, AT SOUTHWEST PUERTO RICO
This ongoing study is examining spatial distribution and taxonomic structure of reef fish larvae across a neritic-oceanic gradient at Southwest Puerto Rico, in order to identify taxa with self-recruitment potential. Samples were obtained during three cruises (Feb/95, Dec/95 and May,96) along three parallel transects (67 00'; 67 03'; and 67 06' W) running perpendicular to the coastline. Six stations, positioned at 6, 10, 13, 17, 29 and 46 Km from the coastline were occupied along each transect for a total of 18 stations per cruise. A total of 34,626 larval fishes were collected representing 81 families of which 56 were from coral reef fishes. Coral reef larval abundance displayed pronounced neritic-oceanic gradients during all three cruises. Conversely, oceanic larval fish abundance was relatively higher offshore. Taxonomic structure at neritic stations (6 and 10 Km) was dominated by larvae of Clupeiformes, Lutjanidae, Pomacentridae, and Gobiidae. The shelf-edge station (13 Km) presented a mixed taxonomic assemblage of reef and oceanic fish larva. Myctophidae were the most abundant larvae at this station followed by reef taxa, such as, Gobiidae, Pomacentridae, Scaridae, Lutjanidae Clupeiformes and Carangidae. Beyond the shelf-edge, total fish larval abundance, particularly of coral reef fishes declined abruptly, while oceanic taxa (Mytophidae, Scombridae, Gonostomatidae, Paralepididae, and Nomeidae increased in relative abundance, representing more than 50% of the total larvae in most samplings. In general , larvae of fishes characterized as small demersal spawners observed neritic distributions. Reef fishes that are pelagic spawners with relatively longer larval duration had oceanic distributions. Nevertheless, important exceptions to this generalized pattern emerge from this study.
Day: Tuesday, Feb. 2
Location: Sweeney Center