Offshore dispersal of Caribbean reef fish larvae:: How far is it?

The taxonomic structure, abundance, and horizontal distribution patterns of larval fishes were examined across a neritic-oceanic gradient off La Parguera, southwest coast of Puerto Rico during three cruises in February 1995, December 1995 and May 1996. Sampling distance contours positioned at 6, 10, 13, 17, 29 and 46 kin from the coastline were occupied along three transects for a total of 18 stations sampled each cruise. A total of 35,024 larval fishes, representing 81 families was collected. Larval fish abundance declined across the neritic-oceanic gradient in each of the three sampling cruises. Coral reef fish larvae were the numerically dominant assemblage as far as 29 kin (OC-29), but declined to less than 5 ind/100m(3) at OC-46, where oceanic type larvae represented more than 85% of the total individuals. This data suggests that the distribution of coral reef fish larvae is mostly restricted to a fringe of less than 46 kin from the coastline off La Parguera, in the northern Caribbean. Larval taxonomic structure at neritic contours (N-6 and N-10) was dominated by Clupeiformes, Gobiidae, Pomacentridae, Blennioidae, and Lutjanidae. The shelf-edge (SE-13) and oceanic contours down to OC-29 presented a mixed taxonomic assemblage of reef and oceanic larvae. Contour OC-46 formed a distinct cluster of 'oceanic type' larvae numerically dominated by Myctophidae (59.5%), Scombridae (7%) and Gonostomatidae (6%). Three basic dispersion patterns of Caribbean coral reef fish larvae can be discerned from this study, one mostly neritic, a widespread oceanic, and one associated with the outer shelf and the shelf-edge. Clupeiformes (sardines and anchovies), Labridae (wrasses) and Lutjanidae (snappers) are presented as model populations for the different dispersion patterns of coral reef fish larvae off La Parguera.