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DIVERSITY AND DISTRIBUTION OF ECHINODERMS IN RUTLAND ISLAND

DIVERSITY AND DISTRIBUTION OF ECHINODERMS IN RUTLAND ISLAND. KOUSHIK SADHUKHAN ZOOLOGICAL SURVEY OF INDIA ANDAMAN AND NICOBAR REGIONAL CENTRE. INTRODUCTION.

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DIVERSITY AND DISTRIBUTION OF ECHINODERMS IN RUTLAND ISLAND

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  1. DIVERSITY AND DISTRIBUTION OF ECHINODERMS IN RUTLAND ISLAND KOUSHIK SADHUKHAN ZOOLOGICAL SURVEY OF INDIA ANDAMAN AND NICOBAR REGIONAL CENTRE

  2. INTRODUCTION The coastal habitats and the offshore benthic zone of Andaman and Nicobar Islands harbour a rich variety of echinoderms, which contributes half of the echinoderm fauna of the Indian subcontinent. Diversity of Echinoderms: In India: 800 species (Approx) In Andaman and Nicobar Island: 427 Species

  3. Objectives of the present study • Species diversity of echinoderms • Species composition • Abundance of echinoderms with their ecological habitat

  4. STUDY SITES • Rutland Island (South Andaman): Coastline area: 60 Km Island areas: 109.3 Km2 • Grass nali (Stn 1): 11027.307’N and 92036.098’E • Macheedera (Stn2): 11°24.233’N and 92°39.952’E • Meethanali (Stn 3): 11028.514'N and E92040.390'E

  5. MATERIALS AND METHODS:

  6. Results Species Composition: 57 species belong to 13 orders and 23 families Dominant Echinoderm Groups: Holothuroids (35.09%)and Echinoids (31.85%). Among 57 species of Echinoderms, Holothuroids represents 20 species and echinoids represents 18 species.

  7. SPECIES DIVERSITY Species diversity is Higher in Stn 2 than other two stations of Rutland Island. Species evenness index shows maximum distribution of echinoderms in Stn 1. Dominant species: Actinopyga mauritiana, Holothuria impatiens, Bohadschia marmorata, Culcita novaguineae , Linckia laevigata, Echinothrix calamaris.

  8. RELATIVE ABUNDANCE Actinopyga mauritiana (18%), Holothuria impatiens (15%) ,Bohadschia marmorata (15%) are most relatively abundant in Rutland Island. Crinoids are least abundant at different sites of Rutland Island. Echinoids species Echinometra mathaei and Echinothrix calamaris shows 6% and 9% of relative abundance respectively in Rutland Island

  9. General observation on ecological habitat of Echinoderms: • Both crinoids and Ophiuroids have preferred and congenial niches in the reefs and life habits suited to the arms. • They feed suspended food to be collected by the mucus secreted by the arms. • Asteroids are carnivorous or surface film scrapers. • Echinoids and holothurians are substrate feeders and mostly found under dead rocks and in sand or reef areas . Echinoids control the excessive growth of algae in a reef ecosystem by feeding on them. • Holothuroids disturb the natural stratification of the sediment and thus acts as a substrata re-workers.

  10. SUMMARY • A total of 57 species were reported from Rutland Island of which Holothuroidea is represented by highest number of species (20 species). • Species richness is higher in Stn2 than other two stations of Rutland island. • As per the relative abundance in the reef habitats, Actinopyga mauritiana (18%) are present in higher percentage of their diversity in the Rutland Island. • From time to time several workers recorded ecinoderms species from India and Indo-West Pacific regions. Those which at present appears to be restricted to A & N Islands are likely to be revealed, through intensive search, to occur on the coast of Indian subcontinent.

  11. THANK YOU

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