Chapter 8 - Marine Ecosystems of Andaman and Nicobar Islands – Species Abundance and Distribution

Abstract

The marine environment of Andaman and Nicobar Islands is diverse in terms of ecosystems and its biodiversity. The location of Andaman and Nicobar Islands in Bay of Bengal, isolated from surrounding land masses by a long distance, remote for long time evolved into unique, uncontaminated and mostly untouched marine ecosystems. Therefore the endemism in organisms is an inherent property of these islands. The tropical climate with tropical evergreen forest and long rainy seasons influences the water quality of surrounding marine ecosystem which intern define the biodiversity of coastal and offshore water ecosystems. The species abundance and distribution in the marine ecosystems such as mangroves, coral reefs, seaweed beds, seagrass meadows, benthic and offshore pelagic environment are discussed with reference to India and Andaman and Nicobar Islands. Further the major flora and fauna available and their distribution in these islands are also discussed. There are about 6400 marine organisms were reported from Andaman and Nicobar Islands. Eventhough the biodiversity of marine ecosystems of these are studied for many decades, most of the areas are largely unexplored. The abundance and distribution of various species of mangroves, seagrass, seaweed, plankton, invertebrates, fishes, reptiles and mammals in both groups of islands are discussed. Further, the fishery of offshore fishes especially tuna resources are also provided in detail. The biodiversity and distribution is a broad topic and hence major ecosystems and organisms abundance are discussed.