Feeding habits of the barred grunt (Conodon nobilis) (Haemulidae: Perciformes) in the surf zone of Praia Grande, São Paulo, Brazil Teodoro Vaske Júnior, Beatriz Figueiredo Mancini, Jéssica dos Santos Muniz Knoeller

Abstract

The feeding habits and size structure of the barred grunt (Conodon nobilis) were studied based on 82 specimens from 35 to 91 mm TL, collected in the surf zone in the city of Praia Grande, São Paulo. Samples were obtained from a beach seine 10 meters long, 2 meters high and 4.0 mm mesh. The fish were kept frozen and in the laboratory the digestive tract was analyzed under a stereomicroscope, taking into acount the type and quantity of food items. The food spectrum of the species was characterized mainly by zooplanktonic crustaceans, with a higher frequency of Mysida (48.59%) and Copepoda (36.05%). It was observed the occurrence of insects in some stomachs, probably associated to the marginal vegetation and  the presence of urban waste. The diet varied according to their length, where fish smaller than 60 mm preferred smaller prey sizes ranging from 1 to 2 mm. The turbulence generated by the waves in the surf zone is important for the feeding of C. nobilis once facilitates the suspension of prey of sandy bottom to the water column and thus prey can be more easily captured.