Growth of the crab Dilocarcinus pagei Stimpson, 1861 (Crustacea, Brachyura, Trichodactylidae) in the Barra Mansa dam, Mendonça, SP

Abstract

This study aimed to evaluate growth rates of Dilocarcinus pagei Stimpson, 1861 from Barra Mansa dam, Mendonça, SP (21°14’27â€ÂS e 49°56’28â€ÂW), provide information on maximum size attained, longevity and growth rates for males and females, and then relate these data with reproductive biology of the species. For this, the carapace width (CW) of 1,340 specimens of D. pagei, 804 males and 536 females, were measured over the period between July/2006 to June/2007, and their individual growth was determined by CW size classes distribution method. Data was grouped in three-months periods and then analyzed with the FISAT software. The normal components were decomposed following the Bhattacharya method and confirmed by NORMSEP routin, which provided the means and respective standard deviations. Growth rates over the three-months periods and the age cohorts were obtained after the means. The obtained curves for males and females, respectively, were LC = 55.36[1-e^{í 0,68 (t+0,056871)}], LC = 63,65[1-e^{í 0,73 (t+0,045956)}]. Females showed growth rate and maximum size larger than males, probably because the larger size favors the gonads development, resulting in larger spawning in a short period of time. Age cohorts analyses indicate seasonal reproduction, with recruitment pulse in spring. These results indicate that these crabs growth rate is related to their reproductive strategy, possibly the main onthogenetic development selective pressure. Age cohorts analyses indicate seasonal reproduction, with recruitment pulse in spring. These results indicate that these crabs growth rate is related to their reproductive strategy, possibly the main onthogenetic development selective pressure.