Fecundity of the arrow crab Stenorhynchus seticornis in the southern Brazilian coast

Abstract

The arrow crab Stenorhynchus seticornis (Brachyura, Majidae), is a common inhabitant of the rocky subtidal along the Brazilian coast. Fecundity and the influence of environmental variables on egg production are investigated in this study. Information on egg size and egg loss through incubation are also provided. Monthly samples were conducted using SCUBA diving, from January to December 1998 in the Ubatuba region (23degrees25'25"S-44degrees52'03"W), south-eastern Brazilian coast. Early broods were used for the estimation of size-specific relationships of fecundity Egg loss was assessed by comparing average egg numbers of early and late broods. The fecundity was estimated in 621.1 +/-339.6 eggs, with an average diameter of 0.48 +/-0.1 and 0.57 +/-0.1 unit for early and late eggs, respectively The number of eggs produced was apparently constant year-round. No significant differences were recorded among monthly fecundity values. The variation of abiotic factors did not show arty relationship with temporal variability of fecundity, suggesting that the environmental effect in egg production is slight at best.