Pesca,reprodução e alimentação da biquara (Haemulon plumieri,Lacépède,1801), na Costa Central de Pernambuco

Abstract

The white grunt, Haemulon plumieri, is a tropical marine fish of relative economic importance, targeted by the artisanal fleet in the state of Pernambuco (Brazil). Although it has been widely caught, very little has been published on the fishery and biology of the species, especially regarding its reproduction. Thus, the main objective of the present study was to study the fishering operations, reproductive biology and feeding habits of the white grunt along the central coast of the state of Pernambuco. We hope that the information obtained might help to assure a sustainable exploitation of this important fishery resource. For the study of the white grunt fishery, data were obtained from the ESTATPESCA databank developed by the Brazilian environmental agency IBAMA, in August of 2007 and through direct interviews with fishermen from the Z1, Z2 and Z4 colonies, locates in the cities of Recife, Paulista and Olinda, respectively. For the study on reproductive biology, a total of 300 specimens caught between May 2003 and September 2005 were measured, among which 111 males and 180 females were macroscopically identified. In the laboratory, the gonads and stomach of each specimen were collected and fixed in a 10% formaldehyde solution. 261 stomachs were examined for the analysis of feeding habits, the contents of which were identified to the lowest possible taxon level. Among a fishery production of 16870.0 t for the state, in 2005, the white grunt was the eighth most caught fish, with a landed production corresponding to 164.5 t. The artisanal fishing communities have relatively similar socioeconomic characteristics, employing the same fishing methods, namely, fish pots, gillnets, seines and hand lines, with the principal fishing product being the mutton snapper. Fork length (FL) of the white grunt specimens sampled ranged from 14.0 to 29.5 cm, with a female to male sex ratio of 1.7:1.0. Mean monthly distribution of the Gonadossomatic Index (GSI) of adult specimens ranged from 0.28 and 1.63 for males and from 1.47 to 4.68 for females. Size at first sexual maturity (L50) was estimated at 20 cm FL for females and 26 cm FL for males. Among the 261 stomachs analyzed, 25 were everted (9.6%), 218 were empty (83.5%) and just 18 had contents (6.9%). Based on the Index of Relative Importance(IRI), the feeding habits of the species was mainly directed at small fish and mollusks. The results presented here are expected to contribute toward the sustainability of this important fishery resource in the state.