Scientia Marina, Vol 79, No 1 (2015)

Spatial distribution and population structure of fiddler crabs in an Indian Sundarban mangrove

Shilpa Sen
Aquatic Bioresource Research Laboratory, Department of Zoology, University of Calcutta, India

Sumit Homechaudhuri
Aquatic Bioresource Research Laboratory, Department of Zoology, University of Calcutta, India


Brachyuran crabs constitute the most abundant faunal component of mangrove ecosystems and support a wide range of ecosystem services. In the present study, seasonal variation of population density and biomass along with demographic categories and sex ratios of four species of fiddler crabs (Uca rosea, Uca triangularis, Uca dussumieri and Uca vocans) from Jhorkhali Island in the Sundarban mangrove were studied in relation to some major environmental parameters (salinity, nutrient content, soil organic carbon, dissolved oxygen, total dissolved solute, etc.) during bimonthly sampling for three consecutive years (2010-2012). Maximum population density and biomass of the ocypodid crabs were recorded during the pre-monsoonal month and minimum values during the monsoon. Different peaks in reproductive activity were observed among seasonal breeders (U. triangularis, U. dussumieri). For U. vocans, the sex ratio peaks declined during the ovigerous period. All four populations were characterized by significantly more males than females. Multiple regression analysis suggested a cumulative effect of several ecological parameters on seasonal fluctuations of the crab population. Breeding periodicity might be controlled by a combination of factors, including temperature, quality of the substratum, food availability for the adult and larval stages, and intertidal zonations.


fiddler crabs; multiple regression analysis; population size structure; Sundarban mangrove; temporal variation

Full Text:



APHA 1998. Standard methods for the examination of water and wastewater (20th ed.). Washington, DC: American Public Health Association, American Water Works Association and Water Pollution Control Federation.

Bezerra L.E.A., Dias C.B., Santana G.X., et al. 2006. Spatial distribution of fiddler crabs (genus Uca) in a tropical mangrove of northeast Brazil. Sci. Mar. 70(4): 759-766.

Binelli A., Sarkar S.K., Chatterjee M., et al. 2007. Concentration of polybrominated diphenyl ethers (PBDEs) in Sundarban mangrove wetland, north eastern part of Bay of Bengal (India). Mar. Pollut. Bull. 54: 1220-1229. PMid:17512955

Botto F., Iribarne O. 2000. Contrasting effects of two burrowing crabs (Chasmagnathus granulate and Uca uruguayensis) on sediment composition and transport in estuarine environments. Estuar. Coast. Shelf Sci. 51: 141-151.

Brower J.E., Zar J.H., von Ende C.N. 1997. Field and laboratory methods for general ecology, 4th edn., McGraw-Hill, New York.

Chakraborty S.K., Choudhury A. 1985. Distribution of fiddler crabs in Sundarbans mangrove esutarine complex, India. In: Bhosale, L.J. (ed.), Proceedings of National Symposium on Biology, Utilization and Conservation of Mangroves, Kolhapur, Shivaji Univ. Press. pp. 467-472.

Chakraborty S.K., Choudhury A. 1992. Population ecology of fiddler crabs (Uca spp.) of the mangrove estuarine complex of Sundarbans, India. Trop. Ecol. 33(1):78-88.

Coelho P.A., Coelho-Filho P.A. 1993. Chave para identificação dos crustáceos decápodos braquiúros encontrados nos biótopos de água salobra do litoral oriental do Nordeste do Brasil. B. Técn. Cient. Cepene 1: 29-56.

Colby D.R., Fonseca M.S. 1984. Population dynamics and somatic growth of the sand fiddler crab Uca pugilator. Mar. Ecol. Prog. Ser. 16(3): 269-279.

Colpo K.D., Negreiros-Fransozo M.L. 2003. Reproductive output of Uca vocator (Herbst, 1804) (Brachyura, Ocypodidae) from three subtropical mangroves in Brazil. Crustaceana 76: 1-11.

Costa T.M., Silva S.M.J., Negreiros-Fransozo M.L. 2006. Reproductive pattern comparison of Uca thayeri Rathbun, 1900 and U. uruguayensis Nobili, 1901 (Crustacea, Decapoda, Ocypodidae). Braz. Arch. Biol. Technol. 49 (1): 117-123.

Crane J. 1975. Fiddler crabs of the world (Ocypodidae: genus Uca). Princeton University Press, Princeton, New Jersey. 736 pp.

Daleo P., Ribeiro P., Iribarne O. 2003. The SW Atlantic burrowing crab Chasmagnathus granulatus Dana affects the distribution and survival of the fiddler crab Uca uruguayensis Nobili. J. Exp. Mar. Biol. Ecol. 291: 255-267.

Diele K., Koch V., Abrunhosa F.A., et al. 2010. The Mangrove Crab Community of the Caeté Estuary, North Brazil: Species Richness, Zonation and Abundance. In: Saint-Paul U., Schneider H. (eds), Mangrove Dynamics and Management in North Brazil. Ecological Studies 211: 251-271.

Drake P., Arias A.M., Rodriguez A. 1998. Seasonal and tidal abundance patterns of decapod crustacean larvae in a shallow inlet (SW Spain). J. Plankton Res. 20(3): 585-601.

Emmerson W.D. 1994. Seasonal breeding cycles and sex ratios of eight species of crabs from Mgazana, a mangrove estuary in Transkei, South Africa. J. Crustac. Biol. 14: 158-168.

FAO (Food and Agriculture Organization of the United Nations) 2007. The world's mangroves 1980-2005. FAO Forestry Paper 153. FAO, Rome.

Ferreira J.G., Bricker S.B., Simas T.C. 2007. Application and sensitivity testing of an eutrophication assessment method on coastal systems in the United States and European Union. J. Environ. Manage. 82: 433-445. PMid:16580121

Frusher S.D., Giddins R.L., Smith III T.J. 1994. Distribution and abundance of grapsid crabs in a mangrove estuary: effects of sediment characteristics, salinity tolerances and osmoregulatory ability. Estuaries. 17(3): 647-654.

Furukawa K., Wolanski E., Mueller H. 1997. Currents and sediment transport in mangrove forests. Estuar. Coast. Shelf Sci. 44: 301-310.

Genoni G.P. 1991. Food limitation in salt marsh fiddler crabs Uca rapax (Smith) (Decapoda: Ocypodidae). J. Exp. Mar. Biol. Ecol. 87: 97-110.

Goodman L.A. 1965. Simultaneous confidence intervals for contrasts among multidimentional proportions. Technometrics 7(2): 247-254.

Grasshoff K., Ehrhardt M., Kremling K. 1983. Methods of sea water analysis. New York: Verlag Chemie Weinheim.

Hartnoll R.G., Bryant A.D. 1990. Size-frequency distributions in decapods crustacea - the quick, the dead, and the cast-offs. J. Crustac. Biol. 10: 14-19.

Hartnoll R.G., Gould P. 1988. Brachyuran life history strategies and the optimization of egg production. In: Fincham A.A., Rainbow P.S. (eds), Aspects of decapod crustacean biology, Symp. Zool. Soc. London 59: 1-9.

Icely J.D., Jones D.A. 1978. Factors affecting the distribution of the genus Uca (Crustacea: Ocypodidae) on an East African shore. Estuar. Coast. Mar. Sci. 6(3): 315-325.

Johnson P.T.J. 2003. Biased sex ratios in fiddler crabs (Brachyura, Ocypodidae): A review and evaluation of the influence of sampling method, size class, and sex-specific mortality. Crustaceana. 76(5): 559-580.

Koch V., Wolff M. 2002. Energy budget and ecological role of mangrove epibenthos in the Caeté estuary, North Brazil. Mar. Ecol. Prog. Ser. 22: 119-130.

Koch V., Wolff M., Diele K. 2005. Comparative population dynamics of four fiddler crabs (Ocypodidae, genus Uca) from a North Brazilian mangrove ecosystem. Mar. Ecol. Prog. Ser. 291: 177-188.

Kristensen E. 2008. Mangrove crabs as ecosystem engineers; with emphasis on sediment processes. J. Sea Res. 59: 30-43.

Leme M. H. A., Negreiros-Fransozo, M. L. 1998. Reproductive patterns of Aratus pisonii (Decapoda: Grapsidae) from an estuarine area of São Paulo northern coast, Brazil. Rev. Biol. Trop. 46: 673-678.

Litulo C. 2004. Reproductive aspects of a tropical population of the fiddler crab Uca annulipes (H. Milne Edwards, 1837) (Brachyura: Ocypodidae) at Costa do Sol Mangrove, Maputo Bay, southern Mozambique. Hydrobiol. 525: 167-173.

Litulo C. 2005. Population biology of the fiddler crab Uca annulipes (Brachyura: Ocypodidae) in a tropical East African mangrove (Mozambique). Estuar. Coast. Shelf Sci. 62: 283-290.

MacIntosh D.J. 1988. The ecology and physiology of decapods of mangrove swamps. In: Fincham A.A., Rainbow P.S. (eds), Aspectsv of Decapod Crustacean Biology. Oxford Clarendon Press, pp. 315-341.

Manna S., Chaudhuri K., Bhattacharyya S., et al. 2010. Dynamics of Sundarban estuarine ecosystem: eutrophication induced threat to mangroves. Saline Systems 6: 8-24. PMid:20699005 PMCid:PMC2928246

Mantelatto F.L., O'Brien J.J., Biagi R. 2003. Parasites and symbionts of crabs from Ubatuba Bay, São Paulo State, Brazil. Comp. Parasitol. 70: 211-214.

Masunari S. 2006. Distribuição e abundância dos caranguejos Uca Leach (Crustacea, Decapoda,Ocypodidae) na Baía de Guaratuba, Paraná, Brasil. Rev. Bras. Zool. 23 (4): 901-914.

Montague C.L. 1980. A natural history of temperate western Atlantic fiddler crabs (genus Uca) with reference to their impact on the salt marsh. Contr. Mar. Sci. 23: 25-55.

Moura O.D., Lamparelli C.C., Rodrigues F.O., et al. 1998. Decomposição de folhas em manguezais da região de Bertioga, São Paulo, Brasil. Proceedings of the IV Simpósio de Escossistemas Brasileiros 1: 130-148.

Mouton E.C., Felder D.L. 1996. Burrow distribution and population estimates for thefiddler crabs Uca spinicarpa and Uca longisignalis in a Gulf of Mexico salt marsh. Estuaries 19: 51-61.

Murai M., Goshima S., Kawai K., Yong H-S. 1996. Pair formation in the burrows of the fiddler crab Uca rosea (Decapoda: Ocypodidae). J. Crustac. Biol. 16: 522-528.

Naskar K. 1993. Plant wealth of the lower ganga delta: An Eco-taxonomical approach (Vols. I and II). New Delhi 110035, Daya Publishing House.

Nelson D.W., Sommers L.E. 1996. Total carbon, organic carbon, and organic matter. In: A.L. Page et al., (ed.) Methods of Soil Analysis, Part 2, 2nd ed. Agronomy. 9: 961-1010. Am. Soc. of Agron., Inc. Madison, WI.

Nobbs M. 2003. Effects of vegetation differamong three species of fiddler crabs (Uca spp). J. Exp. Mar. Biol. Ecol. 284: 41-50.

O'Connor N.J. 1993. Settlement and recruitment of the fiddler crabs Uca pugnax and U. pugilator in a North Carolina, USA, salt marsh. Mar. Ecol. Prog. Ser. 93: 227-234.

Penha-Lopes G., Bartolini F., Limbu S., et al. 2009. Are fiddler crabs potentially useful ecosystem engineers in mangrove wastewater wetlands? Mar. Pollut. Bull. 58: 1694-1703. PMid:19643448

Pinheiro M.A.A., Fransozo A. 2002. Reproduction of the speckled swimming crab Arenaeus cribrarius (Brachyura: Portunidae) on the Brazilian coast near 23°30'S. J. Crustac. Biol. 22: 416-428.

Pinheiro M.A.A., Franzoso A., Negreiros-Franzoso M.L. 1997. Dimensionamento e sobreposiçao de nichos ecológicos dos potunidéos (Decapoda, Brachyura) na Enseada da Fortaleza, Ubatuba, São Paulo, Brasil. Rev. Bras. Zool. 14: 371-378.

Robertson A.I. 1986. Leaf-burying crabs: their influence on energy flow and export from mixed mangrove forests (Rhizophora spp.) in northeastern Australia. J. Exp. Mar. Biol. Ecol. 102: 237-248.

Rodriguez A., Drake P., Arias A.M. 1997. Reproductive periods and larval abundance patterns of the crabs Panopeus africanus and Uca tangeri in a shallow inlet (SW Spain). Mar. Ecol. Prog. Ser. 149: 133-142.

Rosenberg M.S. 2001. The systematics and taxonomy of fiddler crabs: A phylogeny of the genus Uca. J. Crustac. Biol. 21(3): 839-869.

Santos M.A.C., Coelho P.A. 2001. Crustacea Decapoda of the Paripe River Estuary, Pernambuco, Brazil. Hydrobiology 449: 77-79.

Sarkar S.K., Saha M., Takada H., Bhattacharya A., Mishra P., Bhattacharya B. 2007. Water quality management in the lower stretch of the river Ganges, east coast of India: An approach through environmental education. J. Cleaner Production. 15(16): 1459-1467.

Sastry A.N. 1983. Ecological aspects of reproduction. In: Bliss D.E. (ed.), The biology of crustaceans, vol 8. Academic Press, New York, pp. 179-270.

Sokal R.R., Rohlf F.J. 1995. Biometry, 3rd edn. WH Freeman, New York.

Strickland J.D.H., Parsons T.R. 1972. A practical handbook of sea-water analysis. J. Fish. Res. Board Can. 167: 1-311.

Takeda S. 2010. Habitat partitioning between prey soldier crab Mictyris brevidactylus andpredator fiddler crab Uca perplexa. J. Exp. Mar. Biol. Ecol. 390:160-168.

Tam N.F.Y.,Wong W.S. 2000. Spatial variation of heavy metals in surface sediments of Hong Kong mangrove swamps. Environ. Pollut. 110: 195-205.

Wenner A.M. 1972. Sex ratio as a function of size in marine Crustacea. Am. Nat. 106, 321-350.

Wolanski E., King B., Galloway D. 1995 Dynamics of the turbidity maximum in the Fly River estuary, Papua New Guinea. Estuar. Coast. Shelf Sci. 40: 321-337.

Wolff M., Koch V., Isaac V. 2000. A trophic flow model of the Caete mangrove estuary, North Brazil, with considerations of the sustainable use of its resources. Estuar. Coast. Shelf Sci. 50: 789-803.

Wolfrath B. 1992. Burrowing of the fiddler crab Uca tangeri in the Ria Formosa in Portugal and its influence on sediment structure. Mar. Ecol. Prog. Ser. 85: 237-243.

Zar J.H. 1999. Biostatistical Analysis (4th ed.). New Jersey: Prentice Hall, Upper Saddle River.

Copyright (c) 2015 Consejo Superior de Investigaciones Científicas (CSIC)

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Contact us

Technical support