The crab Hepatus pudibundus presents wide abundance in the Brazilian coast and is considered as bycatch in shrimp fishing. This study aims to apply the statistical method "relative growth" to estimate the morphological sexual maturity of this specie in the region of Cananéia, southern coast of São Paulo. The crabs were captured using a shrimp boat equipped with a double-rig trawl net. The study of relative growth is an analysis establishing relations between two body dimensions, obtained by measuring individuals at different stages of life. In the laboratory the crabs were sexed and with a precision digital caliper (0.01mm) the following dimensions will be measured: carapace width (LC), carapace length (CC), right propodus length (CPd), right propodus height (APd), left propodus length (CPe), left propodus height (APe), abdomen width (LA), and additionally for the males, gonopodium length (CG). The relative growth will be based on the allometric equation y = axb. The coefficient "b" amount will be calculated for each biometrical relationship. The data will be log-transformed, plotted in scatter plots, and adjusted using the coefficient of determination (R²) for each relationship. A non-hierarchical K-means cluster analysis will be performed to characterize the correct division into demographic categories, them a covariance analysis (ANCOVA) to test the differences among formed groups in coefficients. So, the amount of the inflection point will be used to estimate the morphological sexual maturity.
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