Ecologia alimentar do tralhoto Anableps anableps (Anablepidae: Cyprinodontiformes) no rio Paracauari - ilha de Marajó, PA

Abstract

The genus Anableps of the family Anablepidae occurs in brackish or salt water from Central America to the northern part of South America, including the Pacific. This genus has a horizontally divided pupil that allows it to explore the environment above and below the water's surface, hence it is known as a four-eyed fish. In general, the shoals feed in the shallows. The present work aims to identify the feeding habit of Anableps anableps through the analysis of stomach contents. Samples were collected from August 2001 to March 2002 from the Paracauari River (00° 43 'SE48° 31 'W) and tributaries. Collections were made with trawls, puçá and tarrafa nets. The collected material was measured (mm), weighed (g), and the digestive tract was removed. The diet was analyzed based on the frequency of occurrence method. The main food items found were plant material (Diatoms algae) with 27.1%, followed by insects (Hymeunoptera, Coleoptera, Lepdoptera, Hemyptera) with 26.2% and inorganic material (mud and sand) (24%). The least frequent were digested organic material (7.3%); Annelidae (7%); small crustaceans (3.3%) and mollusk (1.6%). The paper concludes that the tralhoto is omnivorous, feeding mainly on insects (arboreal, aerial, aquatic and terrestrial) and algae. Its double vision allows it to live in the intertidal region of the Amazon estuary, exploiting both autoctone (algae) and alloctone (insect) resources.