Assessment of a nearshore and an offshore queen conch (Strombus gigas) habitat in the Florida Keys using field and laboratory techniques

Queen conch in the Florida Keys are slowly recovering from overfishing. This study assessed habitat characteristics, metamorphosis and postlarval growth of queen conch in a nearshore and an offshore habitat. The nearshore habitat was dominated by macroalgae while the offshore habitat was dominated by areas of open coarse sediment and seagrass. There was a significant difference among the top six diatom families at each habitat (p < 0.001). The diatom family Naviculaceae was dominant at both sites. No difference in microbial populations was observed (p>0.05). Larvae metamorphosed when exposed to sediment from nearshore and offshore locations (10-40%). Larvae exposed to offshore sediment at 27°C exhibited the highest metamorphic response (∼40%). There was no significant difference in growth rate of postlarvae fed the food present in the sediment from nearshore and offshore locations. This study may help explain aggregation differences between a nearshore and an offshore queen conch habitat.