Relative growth of the fiddler crab, Uca sindensis(Crustacea: Ocypodidae) in a subtropical mangrove in Pohl Port, Iran

Abstract

The relative growth of the fiddler crab Uca sindensis in Pohl Port was studied. Ten 0.5 m2 quadrates were randomly sampled monthly during low tide periods from October 2009 to September 2010. A total of 840 crabs, 449 (53.45%) males and 391(46.5%) ‌ females, were sampled. The Carapace width of males ranged from 5.5 to13.5 mm (mean ± SD) (8.92 ± 2.04), and of females from 5.0 to 11.5 mm (mean ± SD) (7.95 ± 1.34). Carapace height (CH) and Carapace length(CL), height of the major cheliped (HMC) of males, abdomen width of females (AW), major cheliped length (LMC), dactiluse (D), feeding cheliped (CHF) and merouse (M) were employed as dependent variables and carapace width(CW) as independent variable. The relationship between CW × CH was positive in males and females. The equation (Log CH=Log-4.881+4.681LogCW) for males (P < 0.05) and Log CH=Log-1.882+3.299LogCW for females (P < 0.05). The females showed allometric positive growth for CW × AW relation to male (Log AW= Log0.784+1.217Log CW) (P < 0.05). Also four male crabs were found with two major cheliped in this study. Remarkable ontogenetic changes were observed in the allometric growth of the male major cheliped and the female abdomen, indicating that these structures are closely connected to the timing of sexual maturity. The allometric growth of U. sindensis in Pohl Port mangrove differed from other Uca populations so far studied, indicating that growth could have been influenced by environment variables such as food availability, population density, distribution of vegetation, sex ratio, soil temperature , organic matter, different of surface and sediment.