Fecundity of the swimming crab Postunus spinicarpus (Stimpson, 1871) (Crustacea, Brachyura, Portunidae) in South Coast of São Paulo State

• Grant number: 09/11711-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2010
• End date: December 31, 2011
• Field of knowledge: Biological Sciences - Zoology - Morphology of Recent Groups
• Principal Investigator: Marcelo Antonio Amaro Pinheiro
• Grantee: Andre Luiz Pardal Souza
• Host Institution: Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

Fecundity is an important issue to estimate the potencial reproduction and aquaculture of a species. This study aims to estimate the potencial fecundity of the swimming crab Portunus spinicarpus (Stimpson, 1871), captured in South Coastal of the São Paulo State. The specimens were obtained by otter-trawl net conducted in the 100m isobath, with the NPq. "Soloncy Moura" of the CEPSUL/ICM-Bio, during the 2nd Oceanographic Cruise of the UNESP/CLP. Biometry will be held in carapace width (CW, without lateral spines; CWS, with lateral spines) and abdominal width (AW, major width of the 5th somite) of the ovigerous females, using precision calipers (0.05mm). The specimens were distributed into five size classes (CW), with fecundity estimative of each specimen by counting of the number of eggs in ovigerous mass, using the gravimetric method. In fecundity analises will be used only females with eggs in early stage of embryonic development (N=50). Will be held dehydration, cleaning and weighing of each ovigerous mass (analytical balance - 0,001 g), with subsequent counting of the number of eggs in three subsamples (2mg) per ovigerous mass, using a manual counter. Estimative of individual fecundity occurs by simple rule of three, to obtain the average of the total number of eggs (NE) per ovigerous female examined, which will be correlated to the corporal (CW and CWS) and abdominal (AW) sizes. Sets of ordered pairs obtained for the biometric relations NExCW, NExCWS and NExAW will be submitted to the regression analysis by mathematical functions of best fit and biological coherence. The resulting equations will be compared with those published about other portunid species.