Estrutura populacional do caranguejo Dilocarcinus pagei (Decapoda, Trichodactylidae) no rio Araguari, Minas Gerais

Abstract

Dilocarcinus pagei is a species of freshwater crab in the family Trichodactylidae that has a wide distribution in Brazil and is considered an important component of aquatic trophic webs. It is used as bait in sport fishing in some regions, including the Triângulo Mineiro. The aim of this work was to evaluate the population structure of D. pagei in the Araguari river, Minas Gerais. For this purpose, monthly collections were carried out between September 2020 and April 2021 in a stretch of about 300 m from the river. The crabs were collected using sieves and / or manually at night. Crabs were identified according to sex by means of abdomen morphology and the carapace width was measured. The ovigerous females and those carrying juveniles in their abdomen had their eggs and juveniles counted. A total of 180 individuals were collected (102 males and 78 females). Among females, 11 had eggs and/or juveniles. Males showed LC ranging from 13 to 50.20 mm and females from 18.82 to 53.84 mm. The highest frequency of ovigerous and / or juvenile females was recorded in January 2021. The general sex ratio, considering the entire sample period was significantly different from the expected 1:1 ratio, with a higher proportion of males. Females with embryos or juveniles were recorded in four of the seven months of sampling. The number of eggs ranged from 123 to 678 and juveniles from 19 to 806. This study brought population and reproductive information about the species, which may contribute to the understanding of the ecological role of D. pagei in Araguari river basin.