Demographics of a Nearshore Mating Queen Conch (Lobatus gigas) Aggregation on the Southeast Florida Reef Tract

The queen conch, Lobatus gigas (Linnaeus, 1758), is a large gastropod found throughout the Caribbean region, including off Florida. The extent, habitat association, and population demographics of an aggregation were investigated off southeast Florida near a major shipping port. Population surveys were conducted over 4 km ² of hard-bottom habitats to document benthic cover, conch distribution, and size data within 2 km north and south of the shipping inlet. In total, 122 conch were recorded for the entire surveyed area, equating to 70.6 conch ha ^–1 . Mean density was highest south of the inlet. Juvenile and subadult conch were found throughout the study area, but mostly in the westernmost, shallowest hard-bottom habitats. The highest density of adult conch was found in the CPW south of the inlet. Analyses showed that CPW south has a unique community composition dominated by macroalgae and sand. This area was surveyed further using cross-shelf transects measuring conch extent and demographics. Five-hundred-and-twenty-five conch were found, resulting in a density of 495 ha ^–1 . Confirmed mating sightings, females with eggs, and solitary egg masses were found indicating reproduction in this nearshore habitat is successful. The ratio of females with eggs to those without indicated that, although 21.2% of the females with eggs had a thinner lip, the majority had a lip thickness >12 mm. Nearshore mating conch should be a consideration in beach construction projects. Future research should include reconnaissance for other aggregations, monitoring, and comparisons among other nearshore populations.