For the study, 65 specimens of male crabs were captured in an estuary on the northern coast of Brazil. The study area is located in the coastal area of the municipality of São Caetano de Odivelas, on the banks of the Mojuim River, belonging to the northeast mesoregion and the salty microregion, between the coordinates (00°44'14''S, 48°01'77''W). In the region, semi-day tides predominate with amplitudes between 2 to 4 m. In the laboratory, samples of specimens collected from artisanal fisheries in 2014 were stored in freezers and plastic bags. They were weighted with the aid of a precision digital scale (0.1 g). Using a digital calliper (precision 0.01 mm), the following structures were measured: carapace width (distance between the bases of the lateral spines), carapace length (difference between the epistomial spine and the posterior margin of the carapace), width and total length of the right pincer.