Abstract

In the Turks and Caicos Islands (TCI), discarded queen conch shells are important shelter for juveniles of spiny lobster (Panulirus argus), Nassau grouper (Epinephelus striatus), and red hind (Epinephelus gutattus), all species important to local fisheries. Small scale artificial enhancement of conch shells is known to increase the abundance of these species, but use of this strategy on a scale significant for fisheries had not previously been tested. In January 2009, 1,800 conch shells were placed in three plots in a contiguous 600 m long stretch of seagrass in Cockburn Harbour, South Caicos, TCI. Plots were spaced at increasing distance from the reef and were subsequently surveyed 8 times between May 2009 and April 2010. Juvenile spiny lobster, Nassau grouper, and red hind were observed in all three plots. Spiny lobsters were almost 10 times more abundant than groupers. Densities of lobsters peaked in January 2010 at 1 lobster in every 10 to 16 conch shells and densities remained high throughout the study period. Densities of the groupers were substantially lower with a maximum density of 1 Nassau grouper every 75 shells and 1 red hind every 150 shells. Despite being congeners, Nassau grouper were more abundant with increasing distance from the reef and red hind displayed decreasing abundance with distance from the reef. A strategy to enhance nursery function of seagrass with discarded conch shells appears to be most effective for spiny lobsters rather than groupers.

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