Sandy Island Carriacou

In front of Paradise Beach , Carriacou in the West Indies lies a tiny island with bright white sand. Uninhabited and with sparse vegetation, it features an interior lagoon where you can snorkle in knee deep waters. Around Sandy Island you will find some beautiful diving conditions. Sandy Island is a beloved spot for sailing boats to pass the night in the sheltered waters of the interior. A word of caution for sailors: Please protect the corals and dont just drop your anchor on the precious coral formations that still exist there. Protect the environment and keep it all tidy and clean. That way others will be able to enjoy it too.

by D.G. Patriquin(1) and W. Hunte(2)(1)Professor of Biology, Dalhousie University, Canada, & Research Associate, Bellairs Research Institute, Barbados; (2)Director, Bellairs Research Institute, St. James, Barbados & Professor of Ecology and Environmental Sciences, Marine Resource and Environmental Management Program, University of the West Indies, Barbados

Sandy Island is an uninhabited cay lying off the west coast of Carriacou. Surrounded by clear waters and coral reefs, with an extensive white sand beach and quiet water on its south side and a palm canopy on the island, it has long been a treasured spot for Carriacouans. More recently, it has become a favored site for yachters, shore parties from cruise boats and SCUBA divers.

Photos of the island are often used as centerpieces of advertisements for the region. Carriacouans have expressed concern about increasingly large losses of the island to erosion during severe storms, and about degradation of the island and the surrounding reefs believed to be associated with the intensified tourist traffic. Proposals have been made to implement a number of conservation measures. A preliminary survey of the nature and health of the shallow water (0-4 m) coral communities, which are the most important in relation to erosion of the island, was conducted on June 20, 1996 by David Patriquin. He had previously visited the island and taken underwater photos there in 1969. Dr. Wayne Hunte reviewed a draft of the report. The work was conducted as a volunteer activity.

The sea bottom on the south protected side of the island where yachts anchor is sand and rock with some beds of finger coral. These beds have been completely destroyed by anchors. Heavy growth of algae in the area is suggestive of nutrient and organic pollution.

The east, north and west flanks of the island have been built up by growth of the elkhorn coral, Acropora palmata , in the reef crest zone (0.5-3.5 m). Covered by living thickets of this species when Prof. Patriquin visited the site in 1969, today this zone consists of a now dead, algal covered "elkhorn coral framework".

The highly degraded condition of the elkhorn coral is attributable primarily to two diseases which were not of local origin, however, local factors (overfishing and nutrient pollution) may have exacerbated the problem.

The elkhorn coral suffered near 100% mortality at many locales in the Caribbean (including Sandy Island) due to an outbreak of "White Band Disease" in the late 70's/early 80's; it has not since recovered, nor have other species filled its niche.

Unexpectedly, the survey revealed a new population of healthy, living elkhorn coral, probably not more than a few years old, on the east flank of the island. Colonies up to 75 cm maximum linear dimension were observed, in densities of 1-6 colonies per 4 sq meter area. Also in that region, long spined, black sea urchins are abundant, and there is low algal cover of dead coral. Density of living elkhorn coral and of sea urchins in the reef crest zone decline in a gradient from east to west on the north side of the island; correspondingly, algal cover increases, forming thick mats over the old elkhorn coral, towards the west of the island. No living elkhorn coral was observed on the northwest and west flanks. Black sea urchins were observed in only one patch on the west flank; they were maintaining the patch largely free of algae, in marked contrast to the adjacent areas which bore thick algal mats and had no sea urchins. These patterns suggest that re-establishment of elkhorn coral on the east flank was dependent on prior re-establishment of black sea urchins and their grazing down of algae on the old coral. This situation is of considerable interest scientifically, and is especially encouraging in regard to Sandy Island, because if offers the possibility that elkhorn coral is "on its way back". We suggest that the recovery process could be accelerated by establishing " recovery centres" in areas now covered by thick algal mats. This would involve scraping to remove the algal mat, introducing sea urchins to maintain a low cover, and once the urchins have stabilized and algal cover remains low, transplanting elkhorn coral into the sites. Once established, it would be critical that the potential for physical damage to the new colonies by swimmers and boats is reduced to an absolute minimum. Reducing nutrient and organic pollution from yachts and shore parties, and allowing larger standing stocks of herbivorous fishes to develop would further increase the chances of success.

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