A dendrophylliid coral found in the deep seas of India.Special Arrangement  

India is home to 4,371 species of deep-sea fauna, including 1,032 species under kingdom Protista and 3,339 species under kingdom Animalia, a recent publication by the Zoological Survey of India (ZSI) has revealed.

The deep-sea ecosystem is considered to be below a depth of 200 metres, where solar energy cannot support primary productivity through photosynthesis. This publication is the first detailed work on deep-sea organisms of the country.

Published by Ministry of Environment, Forest and Climate Change, the book ‘Deep Sea Faunal Diversity in India’ is the work of five authors and several contributors. India is surrounded by the Arabian Sea, the Bay of Bengal, the Andaman Sea and the Laccadive Sea. Of the 4,371 species, the maximum of 2,766 species has been reported from deep sea areas of the Arabian Sea, followed by 1,964 species from the Bay of Bengal, 1,396 species from the Andaman Sea, and only 253 species from the Laccadive Sea.

RIMS ship investigator

The authors behind the book point out that India is one of the countries that made a pioneering exploration in the deep Indian Ocean region in 1874 by commissioning a RIMS (Royal Indian Marine Survey) ship investigator, which conducted enormous studies in seas around India. “This RIMS investigator continued to work till 1926. After that, several other vessels, including vessels of the Indian Navy and scientists from the ZSI and other institutions, conducted deep sea explorations, gathering information about the fauna. This publication is a result of the work put together by several scientists across three centuries,” C. Raghunathan, ZSI Acting Director, one of the authors of the publication, said.

The marine biologist said deep sea fauna had a vast diversity, starting from unicellular eukaryotes, sponges, corals, echinoderms and fishes, and also mammals.

Kailash Chandra, former ZSI director, said that the deep sea ecosystem was the most unexplored ecosystem across the world. It included hydrothermal vents, submarine canyons, deep sea trenches, sea mounts, cold seeps, and mud volcanoes.