Dinâmica alimentar da pescada branca Plagioscion squamosissimus (heckel, 1840) do lago da hidrelétrica de Tucuruí, Pará

Abstract

Studies about feeding dynamics of carnivorous fish are essential for understanding the trophic conditions of the ecosystem that these fish inhabit and important for the suitable use of a given fishing resource. The aim of this work is to describe the digestive tract of silver croaker and analyze the food’s diversity that makes up the species diet. The study area comprises the Tucuruí hydroelectric lake. In the period from December 2017 to January 2019, five field collection campaigns were performed with different equipment, whose sample totalized 352 individuals. For each silver croaker was recorded the total length, the fullness degree of the stomachs, the digestibility degree of the food and the contents were identified and weighed. 54% empty stomachs were observed, 29% half full, 16% full and 1% inside out. Silver croaker presents a digestive tract similar to other carnivorous fish, with a strong tendency to carcinophage, with shrimp as the main food in all stages of its life cycle, but it was also possible to identify other food items that make up the specie’s diet, such as fish and isopods. In addition, the species when young, tends to feed primarily on shrimp, while the adult has a more diversified diet. The diet of silver croaker is differentiated in gender and seasonality terms, influence the hydrological and rainfall cycle in Tucuruí lake.