Size at sexual maturity of female crabs Sesarma rectum Randall (Crustacea, Brachyura) and ontogenetic variations in the abdomen relative growth

Abstract

ABSTRACT. The aim of the present study was to ascertain the size at sexual maturity in females of the crab Sesarma rectum Randall, 1840 by comparing gonadal maturity to morphologic maturity (using abdomen-width data). The relative growth of the abdomen was analysed for all growth phases (for each 3-mm carapace width size class), and the slopes of the separate allometric relationships were compared through analysis of covariance (ANCOVA) from log e -transformed data to detect changes in the level of allometry during ontogeny. The physiological size at maturity (gonadal criteria) was determined through a logistic curve, indicating the size at which 50% of females presented mature gonads (M 50 = 17.4 mm CW). The highest allometric levels occurred in growth phases 2 and 3 (body sizes ranging from 15 to 21 mm CW), indicating faster growth of the abdomen during those phases. Phases 1 (< 15 mm CW) and 4 and 5 (size classes above 21 mm CW) showed isometric growth. In the study area, a mangrove on the northern coast of the state of São Paulo, Brazil, individuals of S. rectum began to reach sexual maturity from 15 mm CW onward, when the slopes of the relationship of abdomen width to carapace width became positively allometric, indicating a differential growth rate. A gradual decrease in the slope, tending to isometry, occurred during ontogeny, as the animals became larger (older).

Size at sexual maturity, breeding season and fecundity of three-spot swimming crab Portunus sanguinolentus (Herbst, 1783) (Decapoda, Brachyura, Portunidae) occurring in the coastal waters of Karachi, Pakistan

“…This finding agrees with that of Reeby et al (1990a) who studied sexual maturity in male P. pelagicus and P. sanguinolentus from Karwar, west coast of India and Leme (2005) who determined size at sexual maturity of female grapsid crab Sesarma rectum from Brazil.…”

Population dynamics ofSesarma rectum(Crustacea: Brachyura: Grapsidae) in the Ariquindá River mangrove, north-east of Brazil

“…The middle phase, here named 'transitional', is evident from 8.35 to 17.75 mm CW, where we can find either immature or mature crabs. This abdomen pattern growth was observed for other populations of S. rectum (Leme, 2005;Silva et al, 2007), and other species of mangrove crabs, such as Uca thayeri Rathbun, 1900 and Uca maracoani Latreille, 1802-1803 . According to Negreiros-Fransozo et al (2003), the first group of adult females could be represented by primiparous females, but further studies are necessary to confirm such a hypothesis.…”

“…Most of the studies on S. rectum have treated population and reproductive aspects, but all have been carried out on populations in south-eastern Brazil (Mantelatto & Fransozo, 1999;Leme, 2002Leme, , 2004Leme, , 2005Silva & Chacur, 2002;Silva et al, 2007). In view of the ecological importance of S. rectum in the mangrove ecosystem and also because of the lack of studies on this crab in north-eastern Brazil, we designed this study to provide information on its population ecology in mangroves of the Ariquindá River mangrove, Tamandaré, State of Pernambuco, Brazil.…”

Maturidade sexual das fêmeas de Callinectes danae (Crustacea, Decapoda, Portunidae) nos estuários dos rios Botafogo e Carrapicho, Itamaracá, PE, Brasil

“…Então, o uso de mais do que um método para determinar o tamanho da maturidade parece ser apropriado, particularmente se estes métodos são utilizados para estipular o tamanho mínimo legal de espécies explotadas comercialmente (HAEFNER, 1990;ALUNNO-BRUSCIA & SAINTE-MARIE, 1998;OVERTON & MACINTOSH, 2002;LEME, 2005).…”