Ichthyofaunal diversity in Great Nicobar Biosphere Reserve , Bay of Bengal

Ichthyofauna were studied in the inshore waters around Great Nicobar Island; 258 species of fin fishes belonging to 141 genera, 84 families and 18 orders were recorded. New distributional ranges for 147 species, including 3 new of record to the Bay of Bengal, are reported

The Andaman and Nicobar Islands are well known for their rich variety of fish.Rao et al. (2000) reported 539 fish species from the freshwater and marine habitats of the islands.A wide variety of fish species occur in Great Nicobar waters owing to the diversity of marine habitats, including mangroves, creeks, lagoons, estuaries, muddy shores and coral reefs; Dhandapani & Mishra (1998) recorded 88 species belonging to 55 genera, 33 families and seven orders, with Perciformes being the dominant order.Local fisheries provide important food and commercial resources (Kumaran 1973;Marichamy 1974;Sivaprakasam 1976a,b;Menon 1977;Sudarsan 1978;Talwar et al. 1982;Dorairaj & Soundararajan 1985, 1987;Mehta & Devi 1990;Talwar 1990;Rajan et al. 1992;Rao et al. 1992;Dhandapani & Mishra 1993;Rajan et al. 1993;Rao & Devi 1996;Devi & Rao 1997;Dhandapani & Mishra 1998;Devaraj et al. 1999;Rao et al. 2000;Ghosh 2001;Rajaram et al. 2007).The marine fishery resources of the Andaman and Nicobar Islands are estimated to be around 0.244 million tonnes, representing over 6% of the estimated marine fishery potential of India.Annual marine fish landing in these waters is about 27000 tonnes, accounting for 11% of the Indian total (Ghosh 2001).

Materials and Methods
The Andaman and Nicobar islands, located in the Bay of Bengal, include 524 islands of which 30 are inhabited.The 24-island Nicobar island group includes Great Nicobar, which is covered by thick forest (70%) and has a coastal system of reefs, mangroves, estuaries and wetlands (Fig 1).Collections were conducted in three-month periods over three years from August 2000 to July 2003 in primary fishing locations around Great Nicobar (Campbell Bay, Lashman Beach, Jawahal Nullah, Gandhi Nagar, Vijaya Nagar, Laful Bay, Kondul, Pillobhabi, Galathea Bay and River, Kopen Heat) using a variety of fishing gear including shore seines, gillnets, cast nets, hook and line, and scoop nets.Scoop net collections were also made in all the low tide collection stations on both the east and west coasts.Specimens were also procured from Zero Point fish market at Campbell Bay, and landing centers including Gandhi Nagar and Vijaya Nagar.The specimens were fixed in 10% formalin.

Results and Discussion
In the second year of collection, 75 species of new record belonging to 55 genera, 75 species, 40 families and 13 orders were reported.Among these, Perciformes topped the list with 24 families, 34 genera and 50 species followed by Anguilliformes (2 families with 5 genera and 7 species), Scorpaeniformes (2 families with 3 genera and 5 species), Tetraodontiformes and Cyprinodontiformes (2 families with 2 genera and 2 species each), Laminiformes (single family with single genus and species).The orders Clupeiformes, Pleuronectiformes, Syngnathiformes, Siluriformes, Aulopiformes, Elopiformes and Rajiformes were represented by a single family with single genus and species each.In Perciformes, the families Carangidae with six species, Haemulidae and Mullidae with three species each and Lutjanidae with two species are the major families showing new distribution records.
In Anguilliformes, 10 species of muraenid eel including the two species Rhinomuraena quaesita and Moringua bicolor and Neoniphon aurolineatus, belonging to the Holocentridae family under the order Beryciformes, are new distribution records to the Bay of Bengal.In Perciformes, Carangidae with 17 species, Serranidae with 12 species, Lutjanidae, Clupeidae and Pomocentridae with nine species each, Haemulidae with seven species, Apogonidae with four species, Chaetodontidae with five species, Pomacanthidae with two species, Scaridae with three species are the major families which include the commercially

Acknowledgements:
The authors are thankful to the Ministry of Environment and Forests, Government of India for providing financial support; to Shri D.R.K. Sastri, Officer-In-Charge, Andaman and Nicobar Regional Station, Zoological Survey of India, Port Blair for permitting us to make use of the library and laboratory facilities; to Shri.N. Yesu Rathnam, Divisional Forest Officer and Shri B. Chatterjee, Wildlife Warden of Campbell Bay, Great Nicobar Islands for the encouragement and facilities and to the Indian Coast Guard for the logistic support.From the entire survey, 147 species of new distribution records in the study area belonging to 15 orders, 97 genera and 59 families are reported.Among these, Perciformes topped the list with 33 families, 57 genera and 99 species followed by Anguilliformes (3 families with 7 genera and 11 species), Tetraodontiformes (4 families with 6 genera and 7 species), Scorpaeniformes (3 families with 5 genera and 8 species), Clupeiformes (2 families with 4 genera and 4 species).Rhinomuraena quaesita (Muraenidae), Moringua bicolor (Moringuedae) belonging to Anguilliformes and Neoniphon aurolineatus (Holocentridae) of Beryciformes, upon their collection from Great Nicobar Islands form new distributional records to the Bay of Bengal.

Figure 1 .
Figure 1.Map of Great Nicobar Island with fish catch sites in the study.

Table 1 . Lists of new distributional records in the Great Nicobar Biosphere Reserve and
ornamentally important species.