Juvenile Coral Abundance Has Decreased by More Than 50% in Only Three Decades on a Small Caribbean Island

A comparison of the community structure of juvenile hermatypic corals of 2 to 37 m depth at the fringing reefs of Curacao between 1975 and 2005 shows a decline of 54.7% in juvenile coral abundance and a shift in species composition. Agaricia species and Helioseris cucullata, the most common juveniles in 1975, showed the largest decline in juvenile abundance (a 9 and 120 fold decrease in density respectively) with Helioseris cucullata being nearly extirpated locally. In 2005, Porites astreoides contributed most colonies to the juvenile coral community, increasing from 8.2% (in 1975) to 19.9% of the total juvenile community. Between 1975 and 2005, juveniles of brooding species decreased in relative abundance while the abundance of juveniles of broadcast spawning species increased or remained the same. These data illustrate the magnitude of the changes that have occurred in only three decades in the composition of juvenile coral communities.