( Food nicho of marine catfish (Teleostei, Ariidae) in the estuarine lagunar complex of Cananéia (25º S, 48º W)

Abstract

In order to study the food nich of marine catfish, 6 species were collected in a period of 20 months in the estuarine region of Cananéia (25°S, 48°W). The catfish were collected at 14 stations with an otter trawl net and in other 4, with gill net The material examined consisted of 3,914 individuals of Arius spixii (Agassiz, 1829), 639 of Genidens genidens (Valenciennes, 1839), 119  of Netuma barba (Lacépí­¨de, 1803), 140 of Sciadeichthys luniscutis (Valenciennes, 1840), 60 of Bagre marinus (Mitchill, 1814) and 7 of Bagre bagre (Linnaeus, 1766). The composition of the food in each species showed a certain over-lap during the 20 months observed and in all areas where the species were collected. Usually the trophic level was related to the size of the species. However, the young Netuma barba and Bagre marinus belong to a high trophic level, being small in size perhaps because they are large when adults. Due to the habit of oral egg incubation by the male, the percentage of empty stomachs was high during the spawning season (December to January).