Fecundity of the mangrove crab Ucides cordatus (Linnaeus, 1763) (Brachyura, Ocypodidae)

Abstract

Females of the mangrove crab Ucides cordatus were collected in a monthly basis along a 2-year period at the mangrove areas of Iguape, SP, Brazil. Ovigerous individuals were measured (CW, carapace width) and weighed (WW, wet weight). Each brood was weighed (WWE, wet weight of eggs), dried (DWE, dry weight of eggs) and the number of eggs (EN) was recorded. Scatter plots for the relationships EN/CW, EN/WW and EN/WWE were produced, and the data were subjected to regression analysis. Relative average fecundity (F 1) was calculated in different seasons and compared to verify if there were any temporal variation of reproductive intensity. Fecundity in U. cordatus varied from 36.081 to 250.566 eggs according to the size-dependent relationship EN = 15.27CW 2.24 (N = 66; R 2 = 0.69; p<0.001). The other expressions obtained for the relationships were: EN = 3797.6WW 0.813 (N = 56; R 2 = 0.72; p<0.001); EN = 29226WWE 0.775 (N = 54; R 2 = 0.70; p<0.001); and EN = 1093586DWE 0.769 (N = 66; R 2 = 0.86; p<0.001). Ovigerous females were found only during spring and summer, and relative average fecundity differed between these seasons. Relative average fecundity was higher in spring and relative frequency of ovigerous females was higher during summer. Overall reproductive intensity was similar between these seasons. The observed trends are regarded to be related to temperature and photoperiod variations.