Recruitment pattern of Diadema antillarum in La Parguera, Puerto Rico

Recruitment success is one of the factors that may be influencing the slow population recovery of Diadema antillarum at many locations in the Caribbean. D. antillarum recruitment was measured with recruitment plates at monthly intervals from September 2005 to September 2006 at three reefs along an inshore-offshore gradient in La Parguera, Puerto Rico. A total of 275 recruits of D. antillarum were collected at the shelf-edge reef during this 13-month study. Two recruits were collected at the mid-shelf reef and no recruits were collected at the inner shelf reef. Recruitment varied among months at the shelf-edge, with the highest value (1,067 ind/m²) occurring in July 2006. Previous benthic surveys in the La Parguera region have demonstrated higher densities of adult D. antillarum at inshore reefs. The higher recruitment at the shelf-edge suggests that recruitment is not a major determinant of the spatial distribution of the adult population. Recruitment occurring in this study is indicative that sources of larvae were available upstream and larval survival was occurring.