Current Status of the Long-Spined Sea Urchin Diadema Antillarum Puerto Rico
Rodríguez Barreras, Ruber
Sabat, Alberto M. (Consejero)
MetadataShow full item record
Among the key species that contribute to the stability of Caribbean coral reefs is the long spined sea urchin Diadema antillarum (Philippi, 1845), which together with herbivore fishes control macroalgae communities. The sea urchin D. antillarum suffered a mass mortality event in 1983 in the Western Atlantic, and three decades later causes of its slow recover are not evident Here, I answer for questions regarding the biology of the species: i) current status of this species in Puerto Rico Archipelago, ii) the contribution of food items in the diet of Diadema, iii) examine the apparent lack of population recovery of D. antillarum following the demographic modeling approach, and iv) the effect of two wrasses fishes in the population dynamic of this sea urchin. Changes in population structured were addressed by monitoring different populations in the northeastern coast of the Puerto Rico and Culebra. The population vital rates were evaluated using a matrix population model with size/abundance data. The contribution of algal food resources was evaluated using a stable isotope approach, whereas the impact of predators was estimated by removal of Thalassoma bifasciatum and Halichoeres bivittatus at one locality. Results indicated that i) the observed abundances of D. antillarum has not yet returned to pre-mortality levels. However, population densities of the species showed some degree of recovery when we compare with previous studies, ii) local recovery requires the spatial and temporal co-occurrence of high recruitment and survival rates, iii) results support that D. antillarum must be considered an omnivore in terms of assimilation. Further studies, where invertebrate samples were included, may help to clarify and quantify the real contribution of food resources in the diet of D. antillarum, and iv) the two wrasses had a strong effect in size structure and the abundance of smaller size classes.