Nature Environment and Pollution Technology

C. Raghunathan ¹, K. Venkataraman ², P. T. Rajan ¹

Affiliations
1 Zoological Survey of India, Andaman and Nicobar Regional Centre, Port Blair-744 102, Andaman & Nicobar Islands, IN
2 Zoological Survey of India, M-Block, New Alipore, Kolkata-700 053, IN

Abstract

Sea cow (Dugong dugon) is the only extant species in the Family Dugongidae and true herbivorous marine mammal. It is listed as vulnerable to extinction at a global scale by the World Conservation Union (IUCN). The present paper documents the status of dugong in Andaman and Nicobar Islands by collating the published data as well as investigation through undersea surveys in selected places of this archipelago. Based on the existing data on dugong in Andaman and Nicobar Islands, it is observed that over the period of 51 years since 1959, a total of 76 dugongs were recorded either in the form of live or dead. Among them 47 dugongs were from Andaman Islands, whereas 29 encountered from Nicobar Islands. The distribution of this mammal is comparatively high in north Andaman, Ritchie's Archipelago and Great Nicobar Island. Potential threats and managerial strategies for the effective conservation of dugongs in Andaman and Nicobar Islands have also been discussed in the paper.

Keywords

Dugong dugong, Andaman & Nicobar Islands, Extinction.

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C. Raghunathan ¹, C. Sivaperuman ¹, Ch. Satyanarayana ², P. T. Rajan ¹

Affiliations
1 Zoological Survey of India, Andaman and Nicobar Regional Station, Port Blair-744 102, Andaman & Nicobar Islands, IN
2 Zoological Survey of India, 2nd Floor, Fireproof Spirit Building, IndianMuseum Complex, 27, JawaharlalNehru Road, Kolkata-700 016,W. B., IN

Abstract

The density and diversity of corals and their associated faunal communities were investigated by underwater survey in Katchal and Teressa Islands of Andaman and Nicobar Archipelago in order to assess the post-tsunami status of corals. The density of scleractinian corals in Katchal Island is 1-13 colonies/10m², and in Teressa Island it ranged from1 to 18 colonies/10m². Fifteen species of scleractinian corals belonging to 13 genera and 6 families with the species diversity of 0.98 were identified during the survey in Katchal Island. Whereas in Teressa Islands 25 species of corals under 14 genera and 7 families with the species diversity of 1.17 have been reported. The density and diversity of coral associated faunal communities such as zooplankton, octocorals, sponges, molluscs and echinoderms were also studied at both the islands.

Keywords

Corals, Post-Tsunami, Katchal & Teressa Islands, Coral Associated Fauna.

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C. Raghunathan ¹, B. Mehmuna ², C. Sivaperuman ¹, R. Kirubagaran ³

Affiliations
1 Zoological Survey of India, Andaman and Nicobar Regional Station, Haddo, Port Blair-744 102, Andaman & Nicobar Islands, IN
2 National Institute of Ocean Technology, Andaman and Nicobar Centre for Ocean Science and Technology, Port Blair-744 103, Andaman & Nicobar Islands, IN
3 National Institute of Ocean Technology, Pallikaranai, Chennai-600 100, T.N., IN

Abstract

Andaman Sea is partially isolated portion of the northeastern Indian Ocean which lies enclosed between the coast of Burma, Thailand and Malaysia on the east and the chain of Andaman and Nicobar Islands and Sumatra Islands of Indonesia on the west. The biomass, density, diversity and distribution of oceanic zooplankton were studied from 10 stations along the continental slope of Andaman Sea during September 10-20, 2008 by onboard research vessel ORV Sagar Manjusha. A total of 96 species of zooplankton belonging to 19 groups and 74 genera were recorded during the study. Copepods were the dominant group at all the stations and their composition of occurrence ranged from 30.39% at station 4 to 44.30% at station 7. The volume of zooplankton ranged between 4.7mL/100m³ and 12.7mL/100m³ at stations 6 and 3 respectively. However, the numerical density of zooplankton along the study area showed minimum as 17300 No./100m³ and maximum as 31620 No./100m³ at these stations. The data pertaining to physicochemical parameters of seawater were also collected and the results discussed.

Keywords

Oceanic Zooplankton, Diversity, Density, Biomass, Andaman Sea.

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C. Stella ¹, C. Raghunathan ²

Affiliations
1 Department of Oceanography and Coastal Area Studies, Alagappa University, Thondi Campus, Thondi-623 409, T. N., IN
2 Zoological Survey of India, Andaman and Nicobar Regional Station, Haddo, Port Blair-744 102, Andaman & Nicobar Islands, IN

Abstract

Age and growth of the Chicoreus virgineus (Roading 1798) and Muricanthus virgineus (Roading 1798) species were determined using different methods such as size frequency method, probability plot method and Von Bertalanffy's growth equation. Using Peterson's method, male of Chicoreus virgineus was found to attain a maximum length of 7.25cm and the female a length of 10.2cm in the 4^th year. In Muricanthus virgineus male and female attained a length of 8.5cm and 11.4cm respectively in 4^th year. The results of probability plot method revealed that the male of Chicoreus virgineus reached a maximum length of 8.55cm, and the female 10.35cm in the 4^th year. However, in Muricanthus virgineus, the maximum length of 9.4cm in male and 11.00cm in female were found in 4^th year. Using Von Bertalanffy's equation, Chicoreus virgineus male was found to attain a length of 8.85cm, and the female a length of 10.35cm while the male of Muricanthus virgineus calculated as 9.4cm, and the female 11.00cm of lengths in 4^th year.

Keywords

Muricid gastropods, Chicoreus virgineus, Muricanthus virgineus, Palk bay.

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C. Stella ¹, C. Raghunathan ²

Affiliations
1 Department of Oceanography and Coastal Area Studies, Alagappa University, Thondi-623 409, Ramnad district, Tamil Nadu, IN
2 Zoological Survey of India, Andaman and Nicobar Regional Station, Haddo, Port Blair-744 102, Andaman & Nicobar Iclands, IN

Abstract

The present study reported the occurrence of Muricanthus kuesterianus in the Palk Strait region of southeast coast of India as a first hand record. The detailed description of this species has been given with the comparison of its close resembled species Chicoreus virgineus.

Keywords

Gastropoda, Muricidae, Muricanthus kuesterianus, Chicoreus virgineus.

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C. Raghunathan ¹

Affiliations
1 Zoological Survey of India, Andaman and Nicobar Regional Station, Haddo, Port Blair-744 102, Andaman & Nicobar Islands, IN

Abstract

The biomass, density, diversity and distribution of oceanic zooplankton were studied from 25 stations along the continental slope of Andaman waters of Bay of Bengal during February to March 2007. A total of 68 species of zooplankton belonging to 56 genera and 16 groups were recorded from the waters of the continental slope. The biomass of zooplankton in terms of dry weight ranged from 792-2828mg/100m³ while volume and numerical density varied from 8.1-16.2 mL/100m³ and 19240-47223 Nos./100m³ respectively. Copepods were the dominant group in all the stations of study. The results obtained for the physico-chemical parameters of seawater are also discussed in the paper.

Keywords

Oceanic Zooplankton, Zooplankton Volume, Zooplankton Biomass, Species Diversity, Continental Slope, Andaman Waters.

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C. Raghunathan ¹

Affiliations
1 Zoological Survey of India, Andaman and Nicobar Regional Station Haddo, Port Blair-744 102, Andaman & Nicobar Islands, IN

Abstract

Holothurians are commercially important echinoderms, included under Schedule- I category of Wildlife Protection Act 1972. The present status of their density, biomass, diversity, distribution and standing stock has been studied from 18 stations along Palk Bay and Gulf of Mannar region. Apart from that the primary and secondary productivities of these regions were also estimated. It is revealed that the population of holothurians was drastically reduced especially Holothuria scabra and Holothuria spinifera as they give high-quality Beche-de-mer. Holothuria atra is the only species predominantly found at all the stations of study. This paper also discusses the overexploitation of these resources and possible measures to conserve them.

Keywords

Holothurians, Sea Cucumbers, Sea Urchin, Palk Bay, Gulf of Mannar, Beche-de-mer.

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C. Stella ¹, C. Raghunathan ²

Affiliations
1 Department of Oceanography and Coastal Area Studies, Alagappa University, Thondi-623 409, Ramnad District, Tamil Nadu, IN
2 Zoological Survey of India, Andaman and Nicobar Regional Station, Haddo, Port Blair-744 102, Andaman & Nicobar Islands, IN

Abstract

Length-weight and various allometric relationships between different morphological parameters in two muricid gastropods of Chicoreus virgineus and Muricanthus virgineus were studied. The correlation coefficient of the two species was found to be significant (P < 0.001). Significant difference was observed in the analysis of variance for various morphological measurements in males and females of Muricanthus virgineus. Highly significant results were also obtained for both the species in allometry and its correlation coefficient.

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C. Raghunathan ¹, A. Tewari ², Y. Khambhaty ², J. T. Jothinayagam ¹

Affiliations
1 Marine Biological Station, Zoological Survey of India, 130, Santhome High Road, Chennai-600 028,Tamil Nadu, IN
2 Central Salt and Marine Chemicals Research Institute, Bhavnagar-364 002, Gujarat, IN

Abstract

The range as well as mean values for numerical density, fresh weight and dry weight of the epiphytic fauna were lowest on Padina tetrastomatica from Okha and highest on Acrosiphonia orientalis from Diu. High species diversity of epiphytic fauna (>8.0) was observed on Caulerpa recemosa, Acrosiphonia orientalis, Padina gymnospora and Sargassum johnstonii. Some of the species of epiphytic fauna showed host specificity as they were recorded only on particular species of seaweeds. The maximum epiphytic fauna (27 species) was recorded on Caulerpa peltata and Veloniopsis pachynema. The similarity index between stations showed close resemblance for epiphytic fauna. Very high number of epiphytic faunal groups (15) were observed on Halimeda tuna, Caulerpa recemosa and Cystoseira indica. The foraminiferan, gastropod, polychaete, ostrocod and bivalve formed very high proportion (12.39-34.75%) of epiphytic fauna on these seaweeds. The minimum numerical density, and fresh and dry weight of seawater zooplankton were observed at Diu, and the maximum at Veraval. None of the species of zooplankton were common to all four places of study. The maximum percentage of numerical density was constituted by Hyperia medusarum, Conchoecia indica and Amhistegina lessonii at different stations. The species diversity of zooplankton ranged from 1.26 at Diu to 4.12 at Veraval whereas, similarity index ranged from 27.27 at Veraval to 41.67 at Okha. Most or all (at Dwarka) species of zooplankton were found in epiphytic form also. The epiphytic form at four stations were quite similar. However, the reverse trend was observed for zooplankton. The species diversity for epiphytic fauna at 4 stations of study varied in a narrow range while it varied widely for zooplankton. All the groups of zooplankton except Mysid were found in epiphytic form. The group diversity of zooplankton ranged from 0.95 at Diu to 3.90 at Veraval. The fresh and dry weights as well as numerical density of benthic fauna ranged from 4.37g.m^-2, 0.97g.m^-2 and 1387 per m^-2 at Veraval to 10.36 g.m^-2, 3.22 g.m^-2 and 5478 per m^-2 at Dwarka respectively. The Neries versicolar, Tubiculous polychaete, Amhistegina lessonii and Elphidium crispum showed maximum numerical density. The species diversity of benthic fauna was low as it ranged from 0.54 at Veraval to 1.63 at Dwarka. However, the similarity index showed nearly close resemblance between different stations. All the species of benthic fauna recorded from Okha and Veraval were also found in epiphytic form in these places. However, 18.75 and 22.22% benthic fauna at Diu and Dwarka respectively were not found in epiphytic form. The similarity index for plankton and benthic fauna indicated near close resemblance at all the stations except Okha. The species diversity of benthic form was significantly less than planktonic form at different places of study. Some of the species of epiphytic, seawater zooplankton and benthic fauna were specific for a particular station. However, quite a number of a species of fauna were common to all four stations of study. It may be concluded that the zooplankton from seawater and benthic (micro and meio) fauna had significantly influenced the composition of epiphytic fauna of seaweeds. Similarly benthic fauna has also influenced the composition of planktonic fauna of seawater and vice-versa.

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C. Raghunathan ¹, A. Tewari ², Y. Khambhaty ³, J. T. Jothinayagam ¹

Affiliations
1 Marine Biological Station, Zoological Survey of India, 130, Santhome High Road, Chennai-600 028, Tamil Nadu, IN
2 Central Salt and Marine Chemicals Research Institute, Bhavnagar-364 002, Gujarat, IN
3 Central Salt andMarine Chemicals Research Institute, Bhavnagar-364 002, Gujarat, IN

Abstract

The soda ash industry effluent has significantly reduced the species diversity of epiphytic fauna and planktonic fauna of seawater, their numerical density, fresh and dry weight, total number of groups and group diversity as compared to control. However, the reverse trend was shown by benthos. Therefore, considerable degradation in the water quality of seawater as well as epiphytic and planktonic fauna has been observed due to discharge of effluent. Some of the species of epiphytic fauna were specific to effluent affected as well as control sites. The epiphytic molluscan larvae and fish eggs were observed only from effluent affected and control sites respectively. Quite a number of species showed host specificity under effluent affected as well as control conditions. The maximum numerical density on seaweeds under effluent affected and control conditions was shown by Copepods and Foraminiferans respectively. Most of the species of seawater zooplankton as well as benthos from effluent affected as well as control sites were also present as epiphytic forms on different seaweeds. The epiphytic fauna contained significantly higher number of groups and species diversity compared to zooplanktonic and benthic fauna. The Decapods were observed only in benthos whereas Cladocerans, Coelenterate larvae, Cyclopoids, Ostracods and Molluscan larvae were found only in epiphytic fauna. In general, most of the physicochemical parameters of effluent, diluted effluent as well as effluent affected seawaters were many magnitude to considerably high as compared to control seawater. However, magnesium in effluent as well as sulphate and phosphate in the effluent affected seawater showed reverse trend. In general, the effluent has significantly affected the species diversity and biomass production of epiphytic and planktonic fauna. The reduction in growth of epiphytic fauna and zooplankton in the effluent affected region is inhibited due to high concentration of different salts present in effluent affected seawater. However, such salts promoted growth and species diversity of benthos.

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