Clam population ecology in relation to environmental characteristics: A comparative assessment of Tuticorin Bay and Pazhayakayal Estuary, south-east coast of India

Kavitha M; Asha P.S.; Ranjith L; Geetha  Sasikumar; Jamesammal  S.; Ramar Muniswaran B.; Usha Rani A.; Willington S.

doi:10.21077/ijf.2026.73.1.171639-05

Authors

Kavitha M Shellfish Fisheries DivisionCMFRI, Kochi-18
Asha, P.S. Vizhinjam Regional Centre of ICAR–Central Marine Fisheries Research Institute, Vizhinjam-695001, Kerala, India
Ranjith L ICAR-National Academy of Agricultural Research Management, Rajendranagar mandal, Hyderabad- 500 030, Telangana, India
Geetha Sasikumar ICAR–Central Marine Fisheries Research Institute, Kochi - 628 018, Kerala, India
Jamesammal, S. Tuticorin Regional Station of ICAR–Central Marine Fisheries Research Institute, Tuticorin - 620 001, Tamil Nadu, India
B. Ramar Muniswaran Tuticorin Regional Station of ICAR–Central Marine Fisheries Research Institute, Tuticorin - 620 001, Tamil Nadu, India
A. Usha Rani Tuticorin Regional Station of ICAR–Central Marine Fisheries Research Institute, Tuticorin - 620 001, Tamil Nadu, India
S. Willington Tuticorin Regional Station of ICAR–Central Marine Fisheries Research Institute, Tuticorin - 620 001, Tamil Nadu, India

https://doi.org/10.21077/ijf.2026.73.1.171639-05

Abstract

A study was undertaken to assess the population characteristics of clams and their relationship with physicochemical parameters in two ecosystems of Thoothukudi coast viz. Tuticorin Bay and Pazhayakayal Estuary, from July 2021 to May 2022. The study was based on monthly sampling of clam populations and associated physicochemical parameters at three stations (St. 1, St. 2 and St. 3 ) in each of the two locations. In Tuticorin Bay, the total clam density ranged from 16 (St. 3) to 148 nos. m-2 (at St. 2) with the mean density of 65±3.3 nos. m-2. Among the species, Meretix casta was dominant (33%) followed by Gafrarium pectinatum (24%), Marcia opima (22%), Paphia malabarica (21%), and Meretrix meretrix (<1%). The total clam density of Pazhayakayal Estuary ranged from 72 (St. 2) to 632 nos. m-2 (St. 3) with a mean of 311±38 nos. m-2. Both biomass and density of the clams significantly varied between the stations of Tuticorin Bay (p<0.01), whereas at Pazhayakayal Estuary, both parameters were not significantly different (p>0.05). The study further revealed that in Tuticorin Bay, characterised by fine sandy substrates (ranging from 35.01 to 81.62%) with relatively high organic carbon content (0.110 to 0.751%), supported greater species diversity but lower population density. In contrast, the Pazhayakayal Estuary, characterised by coarse sand (13.29 to 77.65%) and hyposaline conditions, supports a high population density dominated by a single species M. casta.

Keywords: Bivalve, Clam density, Physicochemical parameters, Salinity, Soil texture, Species diversity

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Author Biographies

Asha, P.S., Vizhinjam Regional Centre of ICAR–Central Marine Fisheries Research Institute, Vizhinjam-695001, Kerala, India

Principal Scientist
Ranjith L, ICAR-National Academy of Agricultural Research Management, Rajendranagar mandal, Hyderabad- 500 030, Telangana, India

Senior Scientist
Geetha Sasikumar, ICAR–Central Marine Fisheries Research Institute, Kochi - 628 018, Kerala, India

Principal Scientist
Jamesammal, S., Tuticorin Regional Station of ICAR–Central Marine Fisheries Research Institute, Tuticorin - 620 001, Tamil Nadu, India

8
A. Usha Rani, Tuticorin Regional Station of ICAR–Central Marine Fisheries Research Institute, Tuticorin - 620 001, Tamil Nadu, India

Senior Technician
S. Willington, Tuticorin Regional Station of ICAR–Central Marine Fisheries Research Institute, Tuticorin - 620 001, Tamil Nadu, India

Senior Technician

References

Albentosa, M., Fernández-Reiriz, M.J., Labarta, U. and Pérez-Camacho, A. 2007. Response of two species of clams, Ruditapes decussatus and Venerupis pullastra, to starvation: physiological and biochemical parameters. Comparative Biochemistry and Physiology Part B: Biochem. and Mol. Biol., 146(2): 241-249. https://doi.org/10.1016/j.cbpb.2006.10.109

Ampili, M. 2014. Adaptability, Distribution status and phylogeny of selected venerid clams. PhD Thesis, Mahatma Gandhi University, India.

Ampili, M. and Sreedhar, K. S. 2016. Hydrological and sediment parameters affecting the distribution of the venerid clam, Paphia malabarica in two estuaries. Int. J. Sci. Res. Publ. 6:15-30. http://www.ijsrp.org/research-paper-0316.php?rp=P515137

Appukuttan, K. K., Velayudhan, T. S., Laxmilatha, P., Kripa, V., Alloycious, P. S., Vinod, M., Gayatri, G. S. and Narasimham, K. A. 2002. Clam resource in the Astamudi Lake, a tropical estuary in southern India: management and conservation concerns. Mar. Fish. Info. Serv. T&E. Ser. 174:1-4.

APHA, 2005. American Public Health Association (APHA) Standard Methods for the Examination of Water and Wastewater (twenty-first ed.), American Public Health Association, Washington, D.C. p. 46.

Asmus, R. M. and Asmus, H. 1991. Mussel beds: limiting and promoting phytoplankton? J. Exp. Mar. Biol. Ecol. 148:215–232. https://doi.org/10.1016/0022-0981(91)90083-9

Aweng, E. R., Suhaimi, O., Nur Izzati, S., Suhaimi, E. and Nur Izzati, O. 2012. Benthic macroinvertebrate community structure and distribution in Sungai Pichong, Gunung Chamah, Kelantan, Malaysia. Am. Int. J. Contemp. Res. 2(1):163-167.

Balasubrahmanyam, K. and Natarajan, R. 1987. Distribution of Meretrix casta (Chemnitz) in Vellar estuary. J. Mar. Biol. Assoc. India. 29: 144 - 147.

Burd, B. J., Macdonald, R. W., Johannessen, S. C. and Van Roodselaar, A. 2008. Responses of subtidal benthos of the Strait of Georgia, British Columbia, Canada to ambient sediment conditions and natural and anthropogenic depositions. Mar. Environ. Res. 66:S62–S79. https://doi.org/10.1016/ j.marenvres. 2008.08.009

Cacabelos, E., Quintas, P. and Troncoso, J. S. 2008. Spatial distribution of soft-bottom molluscs in the Ensenada de San Simón (NW Spain). Am. Malacol. Bull. 25:9-19. http://dx.doi.org/10.4003/0740-2783-25.1.9

Cervetto, G., Gaudy, R. and Pagano, M. 1999. Influence of salinity on the distribution of Acartia tonsa (Copepoda, Calanoida). J. Exp. Mar. Biol. Ecol. 239:33-45. https://doi.org/10.1016/S0022-0981(99)00023-4

Chapman, M. G. and Tolhurst, T. J. 2004. The relationship between invertebrate assemblages and bio-dependant properties of sediment in urbanized temperate mangrove forests. J. Exp. Mar. Biol. Ecol. 304:51-73. https://doi.org/10.1016/j.jembe.2003.11.019

Clarke, K. R. and Gorley, R. N. 2001. PRIMER v5: User manual, PRIMER-E, Plymouth UK, 91 pp.

Currie, D. R. and Small, K. J. 2005. Macrobenthic community responses to long-term environmental change in an east Australian sub-tropical estuary. Estuar. Coast. Shelf. Sci. 63:315-331. https://doi.org/10.1016/j.ecss.2004.11.023

de Almeida, J. M. B., Gaspar, M. B., Castro, M. and Rufino, M. M. 2021. Influence of wind, rainfall, temperature, and primary productivity, on the biomass of the bivalves Spisula solida, Donax trunculus, Chamelea gallina and Ensis siliqua. Fish. Res. 242:106044. https://doi.org/10.1016/j.fishres.2021.106044

Dickson, A. G. 1998. Reference materials for oceanic carbon dioxide measurement. CDIAC Communication 25: 1-16.

Dharmaraj, S., Shanmugasundaram, K. and Suja, C. P. 2005. Observations on the exploitation of clams in Tuticorin. Mar. Fish. Info. Serv. T&E. Ser. 184:10-11.

Diaz RJ, Rosenberg R (1995) Marine benthic hypoxia: a review of its ecological effects and the behavioural responses of benthic macrofauna. Oceanogr Mar Biol 33:3.

Dunn RJK, Welsh DT, Teasdale PR, Lee SY, Lemckert CJ, Méziane T (2008) Investigating the distribution and sources of organic matter in surface sediment of Coombabah Lake (Australia) using elemental, isotopic and fatty acid biomarkers. Cont Shelf Res 28:2535-2549. https://doi.org/10.1016/j.csr.2008.04.009

Fuller, K. M., Fox, A. L., Jacoby, C. A. and Trefry, J. H. 2021. Biological abundance and diversity in organic-rich sediments from a Florida Barrier Island lagoon. Front. Mar. Sci. 8:768083. https://doi.org/10.3389/fmars.2021.768083

Gaspar, M. B., Pereira, A. M., Vasconcelos, P. and Monteiro, C. C. 2004. Age and growth of Chamelea gallina from the Algarve coast (southern Portugal): influence of seawater temperature and gametogenic cycle on growth rate. J. Molluscan. Stud. 70:371–377. http://dx.doi.org/10.1093/mollus/70.4.371

Gomathi, P., Anil, M. K., Raheem, P. K., Raju, B. and Sasikumar, G. 2017. Emerging clam fishery in Muthalapozhi Estuary. Mar. Fish. Info. Serv. T & E. Ser. 231:23-25.

Grasshoff, K., Ehrharft, M. and Kremling, K. 1983. Methods of Seawater Analysis, 2nd Edn. Verlag Chemie, Weinheim.

Grasshoff. K., Kremling, K. and Ehrhardt, M. 2009. Methods of seawater analysis, 3rd Edn. Wiley-VCH, Weinheim.

Gribben, P. E. 2005. Gametogenic development and spawning of the razor clam, Zenatia acinaces in northeastern New Zealand. N. Z. J. Mar. Freshwater. Res. 39:1287-1296. http://dx.doi.org/10.1080/00288330.2005.9517393

Harkantra, S. N. and Rodrigues, N. R. 2004. Environmental influences on the species diversity, biomass and population density of soft bottom macrofauna in the estuarine system of Goa, west coast of India. Indian J. Mar. Sci. 32:187-193.

Holland, A. F., Shaughnessy, A. T. and Hiegel, M. H. 1987. Long-term variation in mesohaline Chesapeake Bay macrobenthos: spatial and temporal patterns. Estuaries 10:227-245. https://doi.org/10.2307/1351851

Howe, R. W., Regal, R. R., Niemi, G. J., Danz, N. P. and Hanowski, J. M. 2007. A probability-based indicator of ecological condition. Ecol. Indic. 7:793-806. https://doi.org/10.1016/j.ecolind.2006.09.003

Hu, J., Zhang, H. and Peng, P. A. 2006. Fatty acid composition of surface sediments in the subtropical Pearl River estuary and adjacent shelf, Southern China. Estuar. Coast. Shelf. Sci. 66:346-356. https://doi.org/10.1016/j.ecss.2005.09.009

Iriarte, A., Villate, F., Uriarte, I., Alberdi, L. and Intxausti, L. 2015. Dissolved oxygen in a temperate estuary: the influence of hydro-climatic factors and eutrophication at seasonal and inter-annual time scales. Estuar. Coast. 38:1000-1015. http://dx.doi.org/10.1007/s12237-014-9870-x

Jayachandran, P. R., Nandan, S. B., Jima, M., Joseph, P., Xavier, N. D., Sreedevi, O. K., Prabhakaran, M. P. and Joseph, K. J. 2019. Macrobenthic functional feeding groups in a microtidal monsoonal estuary (Kodungallur–Azhikode estuary, India). Reg. Stud. Mar. Sci. 25:100444. https://doi.org/10.1016/j.rsma.2018.100444

Kavitha, M., Chhandaprajnadarsini, E. M., Sasikumar, G., Asha, P. S., Kalidas, C., Ranjith, L., Jamesammal, S. and Willington, S. 2021. Account of bivalve fishery of Tamil Nadu and Puducherry. Mar. Fish. Info. Serv. T&E. Ser. 250:36-37.

Konrad. C. P. 2014. Approaches for evaluating the effects of bivalve filter feeding on nutrient dynamics in Puget Sound, Washington (USGS series No. 2013-5237). US Geological Survey, VA. https://doi.org/10.3133/sir20135237

Kripa, V., Velayudhan, T. S., Joseph, S., Alloycious, P. S., Joseph, M., Radhakrishnan, P. and Jenni, B. 2004. Clam fisheries of Vembanad Lake, Kerala with observations on the socio economic conditions of the clam fisheries. Mar. Fish. Info. Serv. T & E. Ser. 179:14-16.

Kripa, V., Chinnadurai, S., Padmanathan, J., Athipandian, R., Sathakathullah, S. M. and Mohan, R. 2012. Restoration and natural revival of clam populations at Tuticorin Bay, Tamil Nadu after a mass mortality incident. Mar. Fish. Infor. Serv. T & E. Ser. 211:3-4.

Kurup, B.M., Sebastian, M.J., Sankaran, T.M. and Rabindranath, P. 1990. Exploited fishery resource of Vembanad Lake. Part III. Clam fisheries. Mahasagar 23:127–137.

La Valle, P., Nicoletti, L., Finoia, M.G. and Ardizzone, G.D. 2011. Donax trunculus (Bivalvia: Donacidae) as a potential biological indicator of grain-size variations in beach sediment. Ecol. Indic. 11:1426-1436. https://doi.org/10.1016/j.ecolind.2011.03.005

Lagade, V.M., Taware, S.S. and Muley, D.V. 2013. Commerical harvesting and economy of edible clam species in Bhatye estuary, Ratnagiri, India. Ind. J. Mar. Sci. 42:665- 669.

Lake, S. J. and Brush, M. J. 2015. Contribution of nutrient and organic matter sources to the development of periodic hypoxia in a tributary estuary. Estuar. Coast. 38:2149-2171. https://doi.org/10.1007/s12237-015-9954-2

Laxmilatha, P., Velayudhan, T.S., Mohamed, K.S., Kripa, V., Radhakrishnan, P., Jenny Sharma, C., 2006 a. The fishery and biology of Meretrix casta (Chemnitz) in the Moorad estuary, Kerala. Indian J. Fish. 53:109-113.

Laxmilatha, P., Velayudhan, T. S., Mohamed, K. S., Kripa, V., Joseph, M. and Jenni, B. 2006 b. Bivalve resources of the Chettuva estuary, Kerala. Indian J. Fish. 53:481-486.

Laxmilatha, P., Thomas, S., Surendranath, V. G., Sivadasan, M. P. and Ramachandran, N. P. 2011. Bivalve resources of Moorad Estuary, north Kerala. Mar. Fish. Info. Serv. T&E. Ser. 207: 24-25.

Laxmilatha, P. 2013. Population dynamics of the edible clam Meretrix casta (Chemnitz) (International Union for Conservation of Nature status: Vulnerable) from two estuaries of North Kerala, south west coast of India. Int. J. Fish. Aquac. 5:253-261.

Lewis, D. W. 1984. Practical Sedimentology. Hutchinson Ross Publishing Company, Pennsylvania.

Lin, T., Lai, Q., Yao, Z., Lu, J., Zhou, K. and Wang, H. 2013. Combined effects of carbonate alkalinity and pH on survival, growth and haemocyte parameters of the Venus clam Cyclina sinensis. Fish. Shellfish. Immunol. 35:525-531.

Lin, H., Liu, K., Wang, J., Huang, Y., Li, Z., Lin, J., He, X., Zhang, S., Mou, J., Wang, Y. and Xing, B. 2018. Spatial pattern of macrobenthic communities along a shelf-slope-basin transect across the Bering Sea. Acta. Oceanol. Sini. 37:72–81. doi: 10.1007/s13131-018-1192-6.

Liyana, S. H., Sari, L. A., Dewi, N. N., Masithah, E. D., Sahidu, A. M. and Pursetyo, K. T. 2019. Distribution patterns and the biomass of bivalves at SegoroTambak estuary, Sedati, Sidoarjo, East Java. In IOP Conference Series: Environ. Earth. Sci. 236: 012043. IOP Publishing, Bristol, UK. doi: 10.1088/1755-1315/236/1/012043

Macfarlane, G. R. and Booth, D. J. 2001. Estuarine macrobenthic community structure in the Hawkesbury River, Australia: Relationships with sediment physicochemical and anthropogenic parameters. Environ. Monit. Assess. 72:51-78.

Maes, J., Van Damme, P. A., Taillieu, A. and Ollevier, F. 1998. Fish communities along an oxygen poor salinity gradient (Zeeschelde Estuary, Belgium). J. Fish. Biol. 52:534-546.

Manzi, J. J. and Castagna, M. 1989. Clam mariculture in North America. Developments in aquaculture and fisheries science, Vol. 19. Elsevier publication, New York.

Maoxiao, P., Bo, Y., Xiaojun, L., Donghong, N., Tianyi, L., Zhiguo, D. and Jiale, L. 2018. Effects of alkalinity and pH on survival, growth, and enzyme activities in juveniles of the Razor Clam, Sinonovacula constricta. Front. Physiol. 9:552. doi: 10.3389/fphys.2018.00552.

Martins, R., Sampaio, L., Quintino, V. and Rodrigues, A.M. 2014. Diversity, distribution and ecology of benthic molluscan communities on the Portuguese continental shelf. J. Sea. Res. 93:75-89.

Matozzo, V., Chinellato, A., Munari, M., Bressan, M. and Marin, M.G. 2013. Can the combination of decreased pH and increased temperature values induce oxidative stress in the clam Chamelea gallina and the mussel Mytilus galloprovincialis?. Mar. Pollut. Bull. 72:34-40.

Maunder, M. N. and Deriso, R. B. 2013. A stock–recruitment model for highly fecund species based on temporal and spatial extent of spawning. Fish. Res. 146:96-101.

McLachlan, A., Jaramillo, E., Defeo, O., Dugan, J., de Ruyck, A. and Coetzee, P. 1995. Adaptations of bivalves to different beach types. J. Exp. Mar. Biol. Ecol. 187:147-160.

McLeod, R. J. and Wing, S. R. 2008. Influence of an altered salinity regime on the population structure of two infaunal bivalve species. Estuar. Coast. Shelf. Sci. 78:529-540.

McLusky, D. S. 1968. Some effects of salinity on the distribution and abundance of Corophium volutator in the Ythan estuary. J. Mar. Biol. Assoc. U. K. 48:443-454.

Meziane, T. and Tsuchiya, M. 2002. Organic matter in a subtropical mangrove-estuary subjected to wastewater discharge: origin and utilisation by two macrozoobenthic species. J. Sea. Res. 47, 1-11.

Morrisey, D.J., Turner, S.J., Mills, G.N., Williamson, R.B. and Wise, B.E. 2003. Factors affecting the distribution of benthic macrofauna in estuaries contaminated by urban runoff. Mar. Environ. Res. 55:113-136.

Murrell, M. C., Caffrey, J. M., Marcovich, D. T., Beck, M. W., Jarvis, B. M. and Hagy III, J. D. 2018. Seasonal oxygen dynamics in a warm temperate estuary: effects of hydrologic variability on measurements of primary production, respiration, and net metabolism. Estuar Coast 41:690-707.

Nagvenkar, S. S., Ansari, Z. A. and Jagtap, T. G. 2014. Population density, biomass and allometric relationship of shortneck clam Paphia malabarica (Chemnitz, 1782) from estuarine regions of Goa west coast of India. Indian J. Fish. 61:18-23. http://drs.nio.org/drs/handle/2264/5169

Nakamura, Y. and Kerciku, F. 2000. Effects of filter-feeding bivalves on the distribution of water quality and nutrient cycling in a eutrophic coastal lagoon. J. Mar. Syst. 26:209–221. https://doi.org/10.1016/S0924-7963(00)00055-5

Narasimham, K. A. 1991. Present status of clam fisheries of India. J. Mar. Biol. Ass. India 33:76-88.

Nayar, K. N., Mahadevan, S., Rao, K. S., Sivalingam, D. and Ramadoss, K. 1988. Exploitation of molluscan shell deposits in Vigai estuary at Athankarai. CMFRI Bulletin 42:35-39.

Nouri, J. Karbassi, A. R. and Mirkia, S. 2008. Environmental management of coastal regions in the Caspian Sea. Int. J. Environ. Sci. Technol. 5:43-52. https://doi.org/10.1007/BF03325996

Ojea, J., Pazos, A. J., Martınez, D., Novoa, S., Sanchez, J. L. and Abad, M. 2004. Seasonal variation in weight and biochemical composition of the tissues of Ruditapes decussatus in relation to the gametogenic cycle. Aquaculture 238:451–468. https://doi.org/10.1016/j.aquaculture.2004.05.022

Parsons, T. R., Maita, Y. and Lalli, C. M. 1984. A manual of chemical and biological methods for seawater analysis. Pergamon Press, Oxford, UK. DOI: http://dx.doi.org/10.25607/OBP-1830

Parulekar, A.H., Dwivedi, S.N. and Dhargalkar, V.K. 1973. Ecology of clam beds in Mandovi, Cumbarjua Canal and Zuari estuarine system of Goa. Indian J. Mar. Sci. 2:122-126. http://drs.nio.org/drs/handle/2264/5751

Parulekar, A. H., Nair, S. A., Ansari, Z. A., Harkantra, S. N., Chatterji, A., Ingole, B. S. and Roy, J. M. 1984. Ecology and culturing of edible bivalves in Goa. Indian J. Mar. Sci. 13:190-192.

Prandi-Rosa, G. A. and Farache Filho, A. 2002. Evaluation of quality parameters of superficial water in springs from Jales–sp. Holos. Environ. 2:36-51.

Prasanna, M. B. and Ranjan, P. C. 2010. Physico chemical properties of water collected from Dhamra estuary. Int. J. Environ. Sci. 1:334-342.

Queiroga, H., Cruz, T., dos Santos, A., Dubert, J., González-Gordillo, J. I., Paula, J., Peliz, A. and Santos, A. M. P. 2007. Oceanographic and behavioural processes affecting invertebrate larval dispersal and supply in the western Iberia upwelling ecosystem. Prog. Oceanogr. 74:174-191.

Ram Mohan, M. K. and Velayudhan, T. S. (1998). Studies on the salinity tolerance of the venerid clam, Paphia malabarica (Chemnitz). J. Mar. Biol. Assoc. India. 40:185-188.

Rao, K.S., Sivalingam, D., Nair, P.N. and Unnithan, K.A. 1987. Oyster resources of Athankarai estuary, southeast coast of India. CMFRI Bulletin 38:17-29.

Ravindran, K., Appukuttan, K. K., Pillai, V. S. and Boopendranath, M. R. 2006. Report of the committee of experts on ecological and environmental impact of dredging at Vaduthala Kayal and Vaikam Kayal, Kerala. Report submitted to the Government of Kerala, Thiruvananthapuram.

Sadhuram, Y., Sarma, V. V.., Murthy, T. R. and Rao, B.P. 2005. Seasonal variability of physico-chemical characteristics of the Haldia channel of Hooghly estuary. India J Earth. Syst. Sci. 114:37-49. https://doi.org/10.1007/BF02702007

Sivashankar, N., Chethan, N. and Bai, T. C. 2015. Distribution of benthos in relation to different environmental variables in Mulki Estuary. Int. J. Sci. Res. Innov. 2:43-47.

Soares-Gomes, A. and Pires-Vanin, A. M. S. 2005. Bivalve mollusk assemblages on São Paulo’s northern continental shelf, southeast Brazil. Braz. J. Biol. 65:717-727. https://doi.org/10.1590/S1519-69842005000400019

Solorzano. L. 1969. Determination of Ammonia in Natural Waters by the Phenolhypochlorite Method. Limnol. Oceanogr. 14:799-801. https://doi.org/10.4319/lo.1969.14.5.0799

Strickland, J. D. and Parsons, T. R. 1972. A Practical Handbook of Seawater Analysis, 2nd Edn. Fisheries Research Board of Canada, Ottawa, Canada. DOI: http://dx.doi.org/10.25607/OBP-1791

Suja, N. and Mohamed, K. S. 2010. The black clam, Villorita cyprinoides, fishery in the State of Kerala, India. Mar. Fish. Rev. 78:48–61.

Sun, L., Wang, J., Zhang, H. and Xu, M. 2020. Characteristics and Mechanism of the Environmental Capacity Changes in Haizhou Bay, Northern Jiangsu, China from 2006 to 2016. Water 12:2990. https://doi.org/10.3390/w12112990

Tanyaros, S. and Tongnunui, P. 2011. Influence of environmental variables on the abundance of estuarine clam Meretrix casta (Chemnitz, 1782) in Trang Province, Southern Thailand. Songklanakarin J. Sci. Technol. 33:107-115.

Thangavelu, R. and Sanjeevaraj, P. J. 1988. Distribution of molluscan fauna in Pulicat lake. CMFRI Bulletin 42:58-67.

Theresa Paul, T., George, G., Dennis, A., Athira, N. R., Biradar, R. S., Khandagale, R. and Padmakumar, K. G. 2017. Ecosystem responses in the distribution of black clam (Villorita cyprinoides) beds in Vembanad Estuary during environmental changes using GIS and RS. J. Geogr. Inf. Syst. 9:245-266. http://dx.doi.org/10.4236/jgis.2017.93015

Thomas, S. and Nasser, M. 2009. Growth and population dynamics of short-neck clam Paphia malabarica from Dharmadom estuary, North Kerala, southwest coast of India. J. Mar. Biol. Assoc. India. 51:87-92.

Tilburg, C. E., McCartney, M. A. and Yund, P. O. 2012. Across-shelf transport of bivalve larvae: can the interface between a coastal current and inshore waters act as an ecological barrier to larval dispersal?. PLoS One 7:e48960. doi: 10.1371/journal.pone.0048960

Vijaya-Krishna, A. and Ammini, P. 2018. Population characteristics of Villorita cyprinoides in Vembanad Lake, India. Lake Reserv. Manag. 34:130-140. https://doi.org/10.1080/10402381.2017.1394941

Wahid, S. M., Babel, M. S. and Bhuiyan, A. R. 2007. Hydrologic monitoring and analysis in the Sundarbans mangrove ecosystem, Bangladesh. J. Hydrol. 332:381-395. https://doi.org/10.1016/j.jhydrol.2006.07.016

Walkley, A. and Black, I. A. 1934. An examination of the Degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Sci. 37:29–38. http://dx.doi.org/10.1097/00010694-193401000-00003

Warwick, R. M. and Uncles, R. J. 1980. Distribution of benthic macrofauna associations in the Bristol Channel in relation to tidal stress. Mar. Ecol. Prog. Ser. 3:97-103. http://dx.doi.org/10.3354/meps003097

Wilson Jr, W.H. 1991. The foraging ecology of migratory shorebirds in marine soft-sediment communities: the effects of episodic predation on prey populations. Am. Zool. 31: 840-848. https://doi.org/10.1093/icb/31.6.840

Winkler, L. 1888. Methods for measurement of dissolved oxygen. Ber. Dtsch. Chem. Ges. 21:2843–2855.

Zimmerman, A. R. and Canuel, E. A. 2001. Bulk organic matter and lipid biomarker composition of Chesapeake Bay surficial sediments as indicators of environmental processes. Estuar. Coast. Shelf. Sci. 53:319-341. https://doi.org/10.1006/ecss.2001.0815