Condition of Rock-boring sea urchin (Echinometra lucunter) in Puerto Rico

Puerto Rico is an island with one of the highest human population densities (414.78 persons/km²), and its coastal ecosystems are highly impacted by pollutants, coastal development and overfishing. In this study, we use the echinoid Echinometra lucunter as a model organism to assess the effect of pollutants by contrasting density, size structure and body condition among sites that vary in water quality. The objectives of the research are (1) compare the density and size structure of E. lucunter among four sites that vary in anthropogenic impacts and (2) contrast body condition of E. lucunter among these sites. The selected localities in Puerto Rico was Isla de Cabras, Condado Lagoon, Cibuco and Escambrón Beach. Density of E. lucunter was estimated using transect/quadrant methodology. Body condition was estimated by measuring length, width, height and weight of some of the urchins per square meter. Size structure was determinate using the length of urchins measured and these were divided in three classes (small, medium and large). Rock-boring urchins were significantly more abundant in Escambrón Beach than Condado Lagoon with 70.80 ± 30.33 and 3.31 ± 2.86 individuals per m², respectively. Population size structure is indicative of more recruitment occurring at Cibuco. Body condition was highest at Cibuco and lowest at Condado Lagoon. Density, size structure and body condition indicate that the Condado Lagoon is sub optimal, possibly related to higher concentration of contaminants at this site. The next step will be analyzing sea urchin’s tissue to detect heavy metals and contrast with the data collected.