Recruitment and population recovery of Diadema antillarum (Echinodermata; Echinoidea) in Barbados

Abstract

Population recovery of Diadema antrllarum following the Canbbean-wide mass mortality of the urchin in 1983 is documented In Barbados. Recruitment (urchins 10 to 15 mm test diameter) occurred 3 to 4 mo after peak spawning Recruts settled near the front (offshore) of reefs and were aggregated nth adults Populahons grew rapidly on all Barbados reefs the reef with fastest recovery retulning to 57 4 % of t spre-mortality density by December 1985 Reefs nth the hlghest density at the start of the study recovered most rapidly This may suggest that larvae settle preferentially on reefs wlth higher adult densltles, and/or, that luvenile mortality is lower on reefs wlth higher adult densities Populahons of D. antillarum in Domlnica and St Lucia decreased dunng the study Moreover, recruitment strength to each island was posibvely correlated w t hadult denslty on that Island This may suggest that Island populations are dlscrete breeding units Alternatively, the correlation of recruitment strength with island populahon denslty may reflect settlement preference by regionally dispersed larvae for areas of high adult density.