Coral Reef Resources of East Africa: Kenya, Tanzania and the Seychelles

Abstract

Coral reefs are a prominent feature of the East African coastline and associated islands. The Kenya-Tanzania coastline stretches from 1°30'S, at the Somali border to approximately 10°S at the Mozambique border. The Seychelle Islands extend from 5°S to 10°S and 45°E to 56°E (Fig. 1). The climate along the East African coast is dominated by seasonal monsoon winds (northeast monsoon from November to February and southeast monsoon from March to October) and the equatorial currents dictated by the intertropical convergence zone. The narrow East African continental shelf supports fringing and patch reefs which lie 0.5 to 2 km offshore. General profiles of East African coasts are given in Table 1. Gaps in the reefs occur near river mouths notably Tana, Athi and Rufiji, where extensive mangrove stands occur. The islands in the Seychelles group are geologically divided into two groups: the inner granitic islands to the northeast, and the outer coral islands to the south and west. The southern islands lie in the west-flowing South Equatorial Current, whereas the Seychelle Bank Islands lie in the path of the east-flowing South Equatorial Counter Current resulting in differences in climatic and hydrographic conditions. The function of coral reef communities is of-ten underestimated; they build islands and offer coastal protection. The majority of isolated is-lands and island archipelagos of the Indian Ocean are made exclusively of coral deposits. Fifty-one of the ninety-one Seychelle Islands owe their existence to coral growth. Reefs provideprotection to beaches and provide calm boating and diving sites for recreation. Seagrass beds are often associated with clear shallow lagoons. The seagrass beds provide a habitat for economically important juveni1e organisms.