Iheringia, Sér. Zool., Porto Alegre, 96(1):47-52, 30 de março de 2006 Reproductive biology of the sesarmid crab Armases rubripes (Decapoda, Brachyura)... ABSTRACT. The aim of this work was to gain knowledge about reproductive biology of the crab Armases rubripes (Rathbun, 1897) from an estuarine area of the Sepetiba Bay. Samples were taken monthly from February 2003 to January 2004 in the Sahy River estuary (22º56'S; 44º01'W), Rio de Janeiro, Brazil. The crabs were collected by hand during 15-minute catch-effort sessions conducted by two people. In the laboratory, the specimens were separated by sex, carapace width was measured and gonadal stage was checked macroscopically. A total of 830 individuals were caught -304 males, 373 females (60 ovigerous females) and 153 juveniles. The ovigerous females were found almost year-round, except in November and April, showing a continuous reproductive period. They presented a size range from 8.2 to 15.0 mm carapace width (12.1 ± 1.7 mm). Color and macroscopical aspects determined five gonadal stages for males and females (immature, rudimentary, intermediary, developed and resting). First sexual maturity was estimated at 6.5 mm of carapace width for males and 8.1 mm for females. Individual fecundity varied from 200 to 11,460 eggs (4,458 ± 2,739 eggs). Mean egg size was 0.248 ± 0.026 mm, varying from 0.213 to 0.333 mm, while the volume ranged from 0.0051 to 0.0188 mm 3 (0.0082 ± 0.0029 mm 3 ).
Reproductive biology of the sesarmid crab
KEYWORDS.Crab, Sesarmidae, fecundity, reproduction, sexual maturity. Crustaceans exhibit various patterns of life history and reproductive strategies, mainly when habitat is considered. According to MANTELATTO & FRANSOZO (1997), fecundity is an important parameter in determining the reproductive potential of a crustacean species and/or of stock size of a population. GONZÁLEZ-GURRIARÁN & FREIRE (1985) related the importance of sexual maturity for estimating the puberty molt for the examination of external morphological modifications and gonads development.The sesarmid crab Armases rubripes (Rathbun, 1897) is a tropical and subtropical species usually found in salt marshes and estuaries of Central and South America (CAPÍTOLI et al., 1977), widely distributed from Nicaragua to Rio de la Plata, between Uruguay and Argentina (MELO, 1996).According to CAPÍTOLI et al. (1977), FISCHER et al. (1997) and TEIXEIRA & SÁ (1998), these small crabs feed on vegetable debris, mainly roots and stems of Spartina sp. (Poaceae), living inside self-built burrows in muddy substrates or between bromeliad axils. Aspects concerning to biology of this species are restricted to a few studies. CAPÍTOLI et al. (1977) studied this species in the estuarine region of Lagoa dos Patos, Rio Grande do Sul (Brazil); FISCHER et al. (1997) As a contribution to the knowledge of this crustacean, some aspects of the reproductive biology of A. rubripes from an estuarine area were examined (e.g. sexual maturity, breeding period, molting, fecundity and eggs size). After their collectio...
