Volume 66

Using Fishery-independent Surveys to Estimate Densities of Queen Conch, Strombus gigas, Populations in St. Croix, U.S. Virgin Islands

Doerr, J.C. and R.L. Hill
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Date: November, 2013

Pages: 469 – 470

Event: Proceedings of the Sixty six Annual Gulf and Caribbean Fisheries Institute

City: Corpus Christy

Country: USA


Conventional stock assessment methods have been ineffective for determining the population status of queen conch throughout the Caribbean, mainly due to the lack of fishery-independent data. We examined queen conch populations on the northeastern coast of St. Croix, U.S. Virgin Islands, using a radial survey sampling technique with sample sites stratified by depth, habitat type, and management regime, encompassing both open and closed fishing areas. We completed 503 radial surveys and located 4773 conch, representing a cumulative density of approximately 302 conch per hectare. Densities of juvenile conch were highest in open fishing areas outside of Buck Island Reef National Monument (BIRNM) due to larger areas of available seagrass habitat. Densities of adult conch were highest inside the BIRNM on macroalgae and sand where many were observed mating and laying egg masses. Overall length frequencies showed a bimodal distribution, driven largely by conch found within the BIRNM. Length distributions by habitat were variable but showed a trend toward larger conch in reef, macroalgae, and sand habitats compared to a more even distribution in seagrass.

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