Breeding Season and Molt Cycle of the Fiddler Crab Uca rapax (Brachyura, Ocypodidae) in a Subtropical Estuary, Brazil, South America

Abstract

This is the first account of the breeding season and molt cycle of Uca rapax on the Brazilian coast during a one-year period (April 2001-March 2002). At 2 sites, the Itamambuca and Ubatumirim mangrove forests, 2 collectors captured crabs once a month at low tide for 15 minutes by the catch-per-unit-effort procedure, digging into the sediment and removing the crabs. The gonad-development stages of crabs of both sexes were determined by direct observation, and the molt stage was estimated from the hardness of the tegument. Crabs with developed gonads were found mostly in warmer seasons, with ovigerous females occurring mainly in summer and autumn. The reproductive cycle is seasonal. Recently molted individuals were collected in relatively higher numbers for juveniles than for adult crabs.