Uso do habitat e atividade de forrageio de duas espécies de Sparisoma (Labridae: Scarinae), na Área de Proteção Ambiental dos Recifes de Corais, Maracajaú-RN

Abstract

This study focused on the habitat use and foraging activity of juveniles and adults of the parrotfishes S. axillare and S. frondosum (Perciformes: Scarinae) at the Maracajaú Reefs, state of Rio Grande do Norte. The abundance of two species, habitat characteristics, and food availability were recorded along 60 transects (30 m X 2 m). Foraging activity was characterized by 409 direct observations, using "Animal-focal" and "All occurrences" methodologies. Aggregation and agonistic behaviors associated with foraging activity were also recorded. Canonical Correspondence Analysis (CCA) revealed differences in the spatial distribution of S. axillare and S. frondosum, and between different life phases. Juvenile parrotfishes exhibited the highest feeding rate (bites/minute) while adult S. frondosum terminal phase individuals showed the lowest number of bites. Juvenile and adult parrotfishes ate more frequently Mixed substrate and Sand, items containing large amounts of sediments and detritus in their composition. Feeding selectivity differed between S. axillare and S. frondosum, as well as in relation to life phases and food availability. Only 23% (n=95) of the individuals were sighted foraging in aggregations, mostly adult S. frondosum which formed large mixed schools, mainly with Scarus trispinosus and Acanthurus chirurgus. Attacks of Stegastes fuscus against parrotfishes constituted 76% of the agonistic behaviors recorded.