Dinâmica alimentar da piranha branca Serrasalmus calmoni (Steindachner, 1908) no mosaico de unidades de conservação do lago de Tucuruí, Rio Tocantins, Pa

Abstract

The White Piranha, Serrasalmus calmoni, is a carnivorous fish from the Serrasalmidae family, widely distributed in the Tocantins River basin. This study aimed to analyze the feeding dynamics of the White Piranha in the Tucuruí Lake Mosaic of Conservation Units, in the state of Pará, Brazil. Five sampling campaigns were carried out between December 2017 and January 2019. After collection, the individuals were taken for biometric and morphological analysis, including a description of the digestive tract, degree of repletion and degree of digestion. The results indicated that the digestive tract of the White Piranha has characteristics typical of carnivorous fish, such as a wide mouth, poorly developed lips, sharp teeth and a relatively short intestine. Analysis of the stomach contents revealed a predominantly piscivorous diet, with fish accounting for 66.4% of the food items identified. However, plant materials (13.6%), allochthonous insects (4.3%), autochthonous insects (7%), crustaceans (6.4%), seeds (0.7%), molluscs (0.7%) and vertebrates (0.7%) were also found, showing a predominantly piscivorous diet. Analysis of the degree to which the stomachs were full revealed that 60.5% of the individuals analyzed had food in their digestive tracts, indicating a good availability of food resources in the Tucuruí Lake Mosaic of Units. In addition, the data suggest a differentiation in diet between sexes and length classes. Females showed greater dietary diversity than males. In relation to size, juvenile individuals consumed a wider variety of food items, while adults showed a more specialized diet. The study contributes to knowledge of the trophic ecology of Serrasalmus calmoni in Tucuruí Lake, highlighting its ecological importance. In addition, the results indicate that the species adapts well to the environmental conditions of the reservoir, reinforcing its opportunistic characteristic. This information could be fundamental for the conservation of biodiversity in the region.