Biologia reprodutiva do guaiamum, Cardisoma Guanhumi Latreille, 1828 (Decapoda : Gecarcinidae) na Região de Aracati, CE

Abstract

From Dec./06 to Nov./07, 353 specimens of blue crab, C. guanhumi, caught in the Jaguaribe River Estuary, were examined. The mean sex ratio was equal to 1:1 throughout the studied months. The reproductive tract was described both macroscopically and microscopically. The germinative cells in the ovary are oogonia (diameter 14.17 ± 2.02 μm), pre-vitellogenic oocytes (51.02 ± 7.39 μm), vittelogenic oocytes (110.93 ± 9.33 μm), mature oocytes (237.52 ± 22.70 μm), and atretic oocytes. In the testis, the cells were classified, in order of maturation, in: spermatogonia (diameter: 10.5 ± 1.32 μm), spermatocytes (diameter: 9.6 ± 0.52 μm), spermatides (initial phase diameter: 5.6 ± 0.41 μm; final phase diameter: 4.3 ± 0.21) and spermatozoids (diameter: 3.9 ± 0.09 μm). The following stages of ovarian development were identified: immature (translucent, germinative zone containing oogonia and peripheral maturation zone with pre-vitellogenic oocytes); maturing (color ranging from yellow to dark brown; maturation zone with vitellogenic oocytes); mature (dark brown color; predominance of mature oocytes in maturation zone); spawning (dark brown or yellow color, containing non-eliminated residual oocytes; stage observed in ovigerous females); resting (translucent to yellow color, thick gonad wall and residual atretic oocytes). The following stages of testis development are suggested: immature (absence of spermatophores in the posterior vas deferens); and mature (spermatophores in the posterior vas deferens and occasionally in the ejaculatory duct). Female reproductive period starts at August and ends in February, with a peak of activity in November/ December. Ovigerous females were found from November to February. Of all males examined, 37.5% were immature and 62.5% were mature, with no seasonality in such proportion. Size at first sexual maturity, in cephalotorax width, was equal to L50morphometric = 6.12 cm; L50physiological = 5.87 cm, for females, and to 6.91 cm and 6.22, respectively, for males. The size at puberal moult was equal to 6.20 cm and 7.10 cm, for females and males, respectively.