Diet of Nile tilapia in the Cachoeira Alta do Tarumã stream, Tarumã-Açu hydrographic basin (Manaus, Amazonas, Brazil)

Abstract

Trophic plasticity is an important factor in assessing the ability of a species to remain in an altered environment or its ability to be introduced into a new environment. The Nile tilapia is a species that has been illegally introduced for aquaculture purposes in the central portion of the Amazon. Its escape into the natural environment has occurred, and it is already possible to find specimens in streams around Manaus, capital of the state of Amazonas, Brazil. This study aimed to investigate the diet of Nile tilapia in the stream known as Cachoeira Alta do Tarumã (Manaus, Amazonas, Brazil), a small tributary of the Tarumã-açu river that has been affected by anthropogenic actions. To identify its feeding habit, 43 stomachs were analyzed according to their degree of repletion, frequency of occurrence of food items, volumetric method, and the food importance index. The species was identified as being detritivores with a tendency to herbivory. Plastic was identified in the diet of this species, which indicates generalist and opportunistic habits when inserted in habitats with a low supply of food.