Sexual maturity of females of Callinectes danae (Crustacea, Decapoda, Portunidae) in the estuaries of the Botafogo and Carrapicho rivers, Itamaracá, PE, Brazil

Abstract

Callinectes danae (Smith, 1869) is an important fishery resource in the Botafogo and Carrapicho river estuaries. The aim of this study was to estimate the sexual maturity of C. danae. Specimens were captured between October 2003 and June 2004 with the aid of a fishing boat equipped with a wing-trawl and trawling took place during 5 minutes each time. In the laboratory, the crabs were counted, numbered, sexed, weighed, and measured. The carapace width (CW) was measured at the base of the lateral spine and the abdomen width (AW) was measured at the point of the articulation of the fifth abdominal esternite. A total of 596 females of C. danae were analyzed: 417 (69.97%) from Botafogo River and 179 (30.03%) from Carrapicho River; no ovigerous females had CW between 18.38 and 101 mm (59.14 ± 13.65 mm) and 26.70 and 83.48 mm (59.16 ± 13.77 mm), in the respective rivers; the CW of ovigerous females ranged from 57.04 to 83.30 mm (67.68 ± 6.56 mm). The average carapace widths were not significantly different statistically in both estuaries. The knowledge of sexual maturity of C. danae is extremely important for its management and conservation. The gonadal L50 was estimated in 63.58 mm (χ2 = 140.47; df = 1; p < 0.01) and 61.59 mm (χ2 = 90.94; df = 1; p < 0.01) for the estuaries of the Botafogo and Carrapicho rivers, respectively. The morphological L50 was 57.13 mm (χ2 = 484.51; df = 1; p < 0.01) for the Botafogo River and 56.46 mm (χ2= 257.82; df = 1; p < 0.01) for the Carrapicho River. In both estuaries, the morphological maturity of C. danae females occurred before gonadal maturity; thus, to guarantee that this species be managed successfully, fishing must only be allowed for specimens with carapace width over 65 mm.