An assessment of the effects of environment and Human interference on the coral reefs of palk bay and gulf of mannar along the Indian coast

Abstract

The environmental and man-made changes that affects the coral growth and associated animals and fishery in Palk Bay and Gulf of Mannar along the Ind~anc oast are discussed. Quarrying of corals for industrial use has turned out to be a serious threat to the reefs. Removal of corals In several places has caused settlement of sand and growth of sea-grass and algae at former sites of well developed reefs. This is preventing the settlement of planulae and recolonisation of corals. In some of the islands in Gulf of Mannar, there is clear indication of sea erosion due to higher degrees of wave action caused by the removal of reefs that fringed the shores. The reefs of Palk Bay along the Mandapam Peninsula show signs of recolonisation of corals after intensive quarrying coupled with the catastrophic damages caused by the Cyclone of December 1964. Though, there is notable improvement in the number and size of all types of corals, it is the ramose species that are gaining better foothold on the reefs. This visible improvement towards recolonisation was effected within 7 to 10 years after major mortality to corals. It is suggested that prospects of recovery of the reefs in Gulf of Mannar where destruction is significant, is rather bleak since the prevailing environmental conditions are unfavourable for settlement of planulae. Attention is drawn to the necessity of chalking out measures of conservation toprotect what is left of our reefs.