Theses and Dissertations

Defense Date

5-2014

Document Type

Thesis

Degree Name

M.S. Marine Biology

Department

Oceanographic Center

First Advisor

Brian K. Walker

Second Advisor

David S. Gilliam

Third Advisor

Ronald L. Hill

Abstract

The queen conch (Strombus gigas) is a large marine gastropod found throughout the tropical western Atlantic including Florida. Overfishing and habitat loss have led to Caribbean-wide population declines requiring regional protections. On Florida’s east coast, aggregations of conch were previously reported just south of a major shipping port near Ft. Lauderdale, unusually high latitude for the species. This study was designed to investigate the spatial extent and population demographics of the Ft. Lauderdale conch. In summer 2012, broad-scale population surveys were conducted to document benthic cover and conch distribution and size data along 72 random transects stratified across four habitats within 2 km north and south of the inlet. Younger conchs were found throughout the study area, but mostly in the colonized pavement west (CPW) habitat while old conchs were found exclusively at one CPW site south of the inlet. Significantly more conch were found on the CPW south habitat than any other. Benthic cover data suggests that CPW south may have a unique community composition dominated by macroalgae and sand. In summer 2013, the CPW south habitat was surveyed using cross-shelf transects measuring aggregation extent and demographics. Five hundred and twenty five conch were found, at a density of 495 conch per hectare. Confirmed mating sightings, females with eggs, and solitary egg masses were found indicating mating in this nearshore habitat is successful. Future research should include expanded broad-scale surveys to determine if other aggregations exist and monitoring to examine the effects of environmental change on this vulnerable species.

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