Coral Reef Management for Carriacou

Carriacou is the southernmost and largest island in the Grenadines. It has an area of 13 square miles and is populated with about 7,000 people. Carriacou was settled by the French, but in 1763 was ceded with Grenada to the British. The majority of the inhabitants today are of African descent, with the influence in the island mainly British, such as driving on the left, though French names are still noticed, especially in the L’Esterre area. The village of Windward was home to a group of Scottish boatbuilders who settled here in the 19th century. The Scottish names and boatbuilding skills have been passed down through the generations. Many locally built boats from small fishing sloops to large trading schooners are seen in the Carriacou waters. Boat building is still carried out in the traditional way on the beaches but fewer have been built in recent years. The Carriacou Regatta in August is a major event, when yachts from all over the Caribbean compete amid a profusion of carnival activities and fun.

Located at Sanctuary, in the uninhabited northern part of the island, the KIDO PROJECT Bio/Environmental Research Station is directly adjacent to High-North National Park, the most diverse nature reserve of Carriacou and the Grenadines. The KIDO Foundation are promoting the Sandy Island reef restoration project and collaborating with the Committee for Preservation of Carriacou Cays (a Carriacou based citizen’s group) and the Bellairs Research Institute in Barbados. The project developed out of Carriacouans’ concern over increasingly large erosional losses of Sandy Island cay during storms and general degradation of the cay and its living reefs.

The cay is a traditional recreational and fishing site for Carriacouans but more recently it has become a popular anchorage for yachts and for visits by shore parties from cruise ships. In June 1996, a one day survey of the adjacent reefs was conducted by Prof. David Patriquin, who had also visited the site in 1969. The reef crest zone, which consisted of dense living thickets of elkhorn coral in 1969, is today mostly dead and overgrown with seaweed. The die-off of elkhorn coral is attributed to white band disease which caused close to 100% mortality of elkhorn coral through most of the Caribbean in the late 1970s/early 80s.

Similarly, excessive growth of algae is attributed to the epidemic that caused mass mortalities of the herbivorous, long spined black sea urchin, Diadema antillarum on Caribbean reefs in 1982/83. Nutrient pollution from yachts and shore parties at Sandy Island may be contributing to excessive algal growth especially towards the downstream end of the island where it is heaviest. Excessive algal growth seems to have prevented re-establishment of elkhorn coral at Sandy Island through larval settlement. Corals in deeper zones are in generally good condition except for some anchor damage since it is a popular site for divers.

There are encouraging signs of recovery of elkhorn coral on the upstream flank of the island. There, black sea urchins - which are apparently new populations - are maintaining the surfaces of old coral relatively clear of seaweed. Young colonies of elkhorn coral were observed in this area in densities to 6 individuals per 2 x 2 m quadrat. Individual colonies are up to to 75 cm in maximum linear dimension. Sea urchins occur in high densities without elkhorn coral, but elkhorn corals are found only where there are sea urchins, suggesting that recolonization by sea urchins and grazing down of seaweeds was a necessary precursor to settlement and growth of new elkhorn coral.

It is proposed that the re-establishment of elkhorn coral at Sandy Island could be accelerated by establishing “recovery centres”. This would involve manually scraping algae from patches of old elkhorn coral in areas where sea urchins have not re-established, introducing sea urchins to the patches, and once they have proved to be stable and to maintain algal cover at low levels, transplanting pieces of elkhorn coral into the patches.

Carriacou lies south of the main hurricane belt, increasing the odds that new populations would not be decimated by hurricanes, It would also be necessary to minimize potential negative human impacts on the system including physical damage from anchors and boats, disturbance by snorkellers, nutrient/organic pollution from yachts and shore parties, overfishing of herbivorous fishes, and activities that increase the load of sediment, nutrients or toxins in water flowing onto elkhorn coral. Even bringing the algae under control without re-establishing elkhorn coral could be beneficial by allowing more growth of coralline algae which would better stabilize the old elkhorn coral framework in areas where algal growth is now heavy (and cementation by coralline algae minimal).

Coral reef researchers have emphasized that the support and involvement of communities is required for sustainable coral reef management. In the eastern Caribbean, tourists as well as local residents must be sensitized to the needs of coral reefs. Carriacou, in Carib means “land surrounded by reef”, and its people have a long tradition as seafarers and fishermen. Sandy Island has already focused attention of Carriacouans on the issue of coral reef health, it is readily accessible, presents the major types of problems of exotic and local origin that have caused degradation of Caribbean reefs, as well as healthy reefs, and offers an opportunity for testing/developing some novel approaches to coral reef restoration.

A six step program is proposed which will include obtaining baseline scientific data on the status of reefs at Sandy Island and elsewhere in Carriacou, trials of the accelerated reef recovery technique, training local personnel in coral reef ecology, and workshops to stimulate community involvement in coral reef management and ecotourism.

For further information contact:

Dr Marina Fastigi, Director,
YWF-KIDO Foundation,
Sanctuary, Carriacou,
Grenada, West Indies
Tel/Fax: (809) 443 7936. E-mail: kido-ywf@caribsurf.com
URL: http://members.aol.com/ywf/home/kido.html