Estratégias reprodutivas do caranguejo Ucides cordatus (Crustacea; Brachyura; Ucididae)

Abstract

The reproduction is one of the main events in an individual's life, being reported for Brachyura different reproduction strategies. This project has aimed to describe reproductive strategies of the caranguejo-uçá, Ucides cordatus, in mangrove of Igaraçú river - PI, observing the relationship of the reproductive cycle phases with environmental factors. The samples were obtained during one period of 24 months. During this period the values of temperature and pluviosity were monthly registered. Excursion to the mangroves for crabs behavior observation were accomplished in the mating period of, called “andada”. The ovaries and vas deferens of the animals were analyzed and classified regarding the maturation stage. The eggs of ovigerous females were counted to esteem the fecundity. A total of 720 individuals were analyzed. Based on gonad microscopic analysis it was observed that the reproductive period of the species is seasonal and occurs during at the rainy season. This period is determined by females since males are capable to the reproduction throughout year. Based in the gonadal analysis, it was observed the size of the carapace width where 50% of the females and males were mature, was 35.13 mm and 32.71 mm, respectively. For morphologic maturation these values were 46 mm to females with base in the growth of the width of the abdomen and 39.9 and 36.4 mm for males with base in the growth of the length of the chelipeds and length of the gonopod. These values are smaller when compared to the observed for other areas. The fecundity observed for the population studied was also inferior to the one of another area, when compared the fecundity equations. It was verified that the mating of the species occurs during the intermoult. During the "andada" phenomena, the behavior visualized with larger intensity was the liberation of eggs for the abdomen of the female. A small number of mating were observed, as well as fights among males. All these behaviors occurred during the night period, indicating that, for this population, the phenomenon of the "andada" occur with larger intensity at night. Based on results, it was suggested the hypothesis that the high intensity of fishing of the crustacean in the area might have unchained the changes observed in the reproductive strategy of the population when compared the one of other areas.