Aspectos reprodutivos do caranguejo Eriphia gonagra (Fabricius, 1781) (Crustacea: Decapoda: Brachyura: Eriphiidae) em um ambiente recifal brasileiro

Abstract

The present study was developed in order to understand the reproductive process of Eriphia gonagra, through the microscopic description of the gonadal stages of the females of E. gonagra, their germ cells and their stages of cell development; estimate the reproductive period correlating with abiotic data and seasonal variation; identify aspects of relative growth; determine the size of the first physiological maturation (LC50) and the type of spawning on the coast of Pernambuco. The collections were carried out monthly on the beach of Gaibu from November / 2018 to October / 2019, during the low tide of spring. According to the results, based on the morphological characteristics of the cells and their observed changes, were identified five stages of cell development: oogonias (7,10 ± 1,85 μm), pre-citellogenic oocytes (42,23 ± 8,61 μm), oocytes in initial vitelegesis (130,49 ± 21,93 μm) vitelogenic oocytes (139,68 ± 23,45 μm) and mature oocytes (214,77 ± 90,81 μm). The gonadal maturation stages were defined and related to the color of the gonads and the degree of development of the germ cells, where 5 maturation stages were identified: 1 - Immature, 2- In initial maturation, 3 - In maturation, 4 - Matura, 5 - Spawned / Rest. Ovigerous females were observed in stages 3.4 and 5. The anatomy of the female reproductive system of E. gonagra, follows the pattern of brachyúros. In total, 183 specimens of Eriphia gonagra were collected, 88 females (48,08%) and 95 males (51,91%). Females showed LC values between 14,65 and 42,54 mm, with their fashions between 24 and 32 mm. For males, the LC ranged from 16,23 to 39,36 mm, with their fashions between 26 and 32 mm. The total sexual proportion differed significantly from what was expected over the sample period: with an average of 1: 0,92 (M / F), it did not correspond to the expected proportion, which is 1:1 (²= 91,79). Analyzing the adjustment of the dose-response model, the first maturation size of the females of Eriphia gonagra LC50 is 21,81 mm and reaching LC99 with 27,35 mm. For males, the LC50 was 20,58 and LC99 26,70 mm. Both sexes showed positive allometry. Through microscopic analysis of the different stages of the germ cells, it can be said that the spawning is fragmented, of the type "synchronous in more than two groups", that is, the specimens have at least three intraovarian lots and spawn two or more times in each reproductive period. Based on observations in the distribution of maturation stages, it is noticed that the reproductive period is continuous, with females in different stages during all months, with a higher incidence of ovigerous females, in final maturation and matures in the hottest months, in December to March.