Biologia populacional de Anomalocardia brasiliana (Gmelin, 1791) (Bivalvia, Veneridae): uma análise comparativa nas praias de Bom Jesus dos Pobres e Cabuçu, Recôncavo Baiano

Abstract

The Baía de Todos os Santos is in Recôncavo of Bahia, Brazil. It has an approximate area of 1000 km2, with greater indentation of the Brazilian coast. Saubara city and their districts Cabuçu and Bom Jesus dos Pobres are in northwest part of Baía, with beaches with intertidal region, where we can find benthic organisms buried in the substrate, including some bivalve molluscs. Anomalocardia brasiliana, known as chumbinho, Veneridae family has a great potential for cultivation in order to its food and socio-economic interests. Thus, this study aimed to perform a descriptive and comparative analysis of the length and weight frequency distribution of the specie A. brasiliana, as well as meat yields and shell and weight x length. Considering the importance of marine bivalve reproduction studies, the study assessed the reproductive behavior of the species, highlighting the sex ratio, the minimum size at first maturity and macroscopic stages of gonadal development. The studied areas were Cabuçu and Bom Jesus dos pobres beaches, in Saubara, Bahia. 12 samples, of August/2009 to July/2010, were collected with biometrics of individuals. The statistical treatment by Bioestat 5.0, was used in order to obtain satisfactory results for such purposes, it was also performed to compare the variables between the two locations by the non-parametric "Mann-Whitney test." 685 individuals were collected on Bom Jesus dos Pobres beach and 675 on Cabuçu beach. It was observed that the average length of shells (Lt, mm) of A. brasiliana, on Bom Jesus dos Pobres beach was 20:18 mm (+4.17) and on Cabuçu beach was 21.26 mm (+3.48). The average weight of the meat of individuals (Wb, g) on Bom Jesus dos Pobres beach was 0.36 g (+0.20) and on Cabuçu beach this value was 0.41 g (+ 0.18). The average weight of the shell (Wsh, g) was 2.79 g (+ 1.38) on Bom Jesus dos Pobres beach and 2.94 g (+ 1.20) on Cabuçu beach. The total weight (Wt, g) of A. brasiliana were 3.15 g (+ 1.57) and 3.36 g (+ 1.36) on Bom Jesus dos Pobres and Cabuçu beaches, respectively. The variation coefficient at both locations for all biometric results, showed heterogeneity. The average yield of meat (Re, b%) on Bom Jesus dos Pobres beach was 11.14% (+ 2.87) and on Cabuçu beach was 12.3% (+ 2.10). The average income of the shell (Re sh %) found on on Bom Jesus dos Pobres beach was 88.86% (+ 2.87) and on Cabuçu beach was 87.97% (+ 2.10). The comparison of variables between the beaches showed no significant differences in the variables Wt and Wsh, but differences were found in Lt, Wb, Re b Re sh. In the A. brasiliana population, in both sampling points was possible to observe positive allometric growth to Wb x Lt. It was observed a negative allometric growth to Wt x Lt. The sex ratio (female: male) on Bom Jesus dos Pobres beach was 1.15:1. In Cabuçu beach, found a ratio of 1:1,12. The length at first sexual maturity of individuals in both beaches had similar values, on Bom Jesus dos Pobres beach with 13.05 mm and Cabuçu beach with 13.41 mm. In the sampled areas was possible to find the occurrence of continuous removal of gametes.