Ecologia Alimentar de Astyanax lacustris (Osteichthyes: Characidae) na Lagoa do Piató, Assu, Rio Grande do Norte, Brasil

Abstract

RESUMO: O presente trabalho baseia-se na análise do conteúdo estomacal de Astyanax lacustris, capturados mensalmente no período de setembro de 2006 a agosto de 2007 na Lagoa do Piató, Assu, Rio Grande do Norte, Brasil. Como instrumento de captura utilizou-se rede de espera com malha de 4 cm entrenós. Foram obtidos de cada exemplar o comprimento total, comprimento padrão, massa corporal total e peso do estômago. A análise do conteúdo estomacal de 360 peixes foi realizada de acordo com o método volumétrico, de pontos e o método de frequência de ocorrência, aplicando-se sobre este o Índice de Importância Alimentar. Os estômagos tiveram o grau de repleção determinado e foi calculado o Índice de Repleção. As variações na dieta e a frequência de ingestão alimentar foram relacionadas com a pluviosidade e os fatores limnológicos. Os itens alimentares identificados foram separados em grupos distintos de acordo com a sua origem. Concluiu-se que a espécie apresenta hábito alimentar onívoro, com tendência à insetivoria e com maior atividade alimentar durante a estiagem. A concentração do oxigênio dissolvido teve maior relação com a frequência de alimentação do que a pluviosidade e os demais fatores físico-químicos da água.Palavras-chave: dieta, peixe, insetivoria, lagoa, estiagem.ABSTRACT: Feeding ecology of Astyanax lacustris (Osteichthyes: Characidae) from Lagoa do Piató, Assu, Rio Grande do Norte, Brazil. This study reports on the stomach content analyses of the Astyanax lacustris captured on a monthly basis from Lagoa do Piató, Assu, Rio Grande do Norte, Brazil, during the period of September, 2006 to August, 2007. The fish were captured using gillnets of 4 cm mesh size. The total length, standard length, body mass and stomach weight were registered for each fish. The stomach contents analyses of 360 fishes were carried out based on volumetric method, points, frequency of occurrence and applying the Relative Importance Index. The degrees of repletion of the stomachs were determined and the Repletion Index was calculated. The diet variations and frequency of ingestion were related to the rainfall and limnological parameters. The food items identified were separated into distinct groups according to their origin. It is concluded that this species shows an omnivorous feeding habit with a tendency towards insectivory, with intensive feeding during the dry season. The concentration of dissolved oxygen was more closely related to.feeding activity than the rainfall and the other physico-chemical factors of the water.

Daily variation feeding of Astyanax lacustris (Lütken 1875) in a subtropical river

“…The diversity of alimentary items in the stomach of A. lacustris shows that this species is omnivorous, which confirms what was verified in other studies (Rocha, Cassati, & Pereira, 2009;Silva et al, 2012). The high incidence of filled stomachs at all times indicates that this lambari feeds at all times of the day.…”

“…The species Astyanax lacustris (Lütken, 1875) is considered omnivorous for feeding on animal and plant items (Silva, Pessoa, Costa, Chellappa, & Chellappa, 2012). Authors such as Andrian, Silva, & Peretti (2001) and Dias, Castelo Branco, & Lopes (2005) emphasize the predominance of plant remains and insects in their diet, characterizing them as omnivores with a herbivore-insectivorous propensity.…”

Diet of Hemigrammus marginatus (Characiformes: Characidae) in the Upper Contas River, Diamantina Plateau (Bahia, Brazil)

“…Although H. marginatus has been classified as zooplanktivore, there was a greater consumption of insects (Diptera and Hymenoptera) in Ressaco do Manezinho and Cladocera in Ressaco do Bile. In this approach, it is important to highlight that some food resources found in the diet of species with generalist or opportunistic habits do not necessarily means a preference for that food, but may reflect the abundance of this resource in the environment or represent an accidental ingestion (Bennemann et al, 2000;Silva et al, 2012).…”

Diet of two insectivorous fish species in a Brazilian semiarid reservoir

“…This knowledge is fundamental for the conservation of ecosystems (Pessoa et al 2012), especially in the semiarid regions of northeast Brazil. These regions are characterized by long periods of drought, a factor that affects food availability and causes changes in fish diet (Santos et al 2014) in different seasons of the year (Silva et al 2012a).…”