Open AccessSpatial distribution and population structure of fiddler crabs in an Indian Sundarban mangrove
Author(s) -
S. K. Sen,
Sumit Homechaudhuri
Publication year - 2015
Publication title -
scientia marina
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 68
eISSN - 1886-8134
pISSN - 0214-8358
DOI - 10.3989/scimar.04121.15a
Subject(s) - mangrove , fiddler crab , biology , biomass (ecology) , intertidal zone , ecology , population , population density , salinity , range (aeronautics) , ocypodidae , ecosystem , crustacean , decapoda , materials science , composite material , demography , sociology
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