RESUMO
We investigated the influence of temporal and spatial factors on the feeding habits of the armed snook Centropomus armatus (Centropomidae), the most abundant snook species in eastern Pacific mangrove ecosystems. The influence of the combination of semi-diurnal tides and diel cycles and salinity on the intertidal abundance, stomach fullness, diet composition and daily consumption of this species was investigated over 1 year in the macrotidal Colombian Pacific coast (Bahía Málaga). The abundance of juvenile C. armatus (5.6-23.6 cm total length) in the intertidal creeks was highest during neap tide-night conditions and lowest during spring-tide day conditions. Centropomus armatus fed predominantly on crustaceans (Alpheidae and Palaemonidae) and fishes. Stomach fullness index (ISF ), a proxy of feeding activity, was not influenced by salinity, but by tidal-diel conditions. Stomach fullness index was highest during neap tide nocturnal inundations, but lowest during diurnal neap tides. Nevertheless, the total daily consumption was higher at spring tide than at neap tides. Higher water temperatures in creeks during neap tides at night could explain not only high C. armatus abundance, but also greater accessibility to active prey. Comparison with the feeding patterns of fishes from other macrotidal mangrove ecosystems suggest that the habitat use and feeding patterns of intertidal fishes in mangroves are strongly influenced by the combination of spring-neap tide and diel cycles. However, the interaction between mangrove geomorphology and flooding regime of the specific mangrove forest might also play a role and deserves further investigation.
Assuntos
Ritmo Circadiano , Ecossistema , Comportamento Alimentar/fisiologia , Perciformes/fisiologia , Animais , Brasil , Dieta , Oceano Pacífico , Densidade Demográfica , Salinidade , Estações do Ano , Ondas de Maré , Clima Tropical , Áreas AlagadasRESUMO
To examine the temporal patterns in the occurrence of a tropical ichthyofauna, fisheries-independent samples were collected between September 2003 and July 2004 from intertidal mangrove creeks in the Curuçá estuary, Pará, north Brazil. Juveniles occurred year-round with the most intense occurrence during the wet/dry transition season (Anchovia clupeoides, Cetengraulis edentulus, Rhinosardinia amazonica, Mugil sp.). The occurrence of Colomesus psittacus and Anchoa hepsetus was continuous. Sciades herzbergii displayed two peaks (wet and dry season) while Cathorops sp. peaked only in the wet season. The continuous presence of juveniles in the tropical mangroves suggested that the fisheries management should be based on large no-take areas rather than closed seasons.
Com o objetivo de examinar padrões temporais em recrutamento de uma ictiofauna tropical, pescarias experimentais foram realizadas entre setembro 2003 e Julio 2004 em canais de maré com vegetação de mangue no estuário do rio Curuçá, Pará, Norte do Brasil. Juvenis ocorreram durante todo o ano, entretanto com maior intensidade no período de recrutamento, durante a transição da estação chuvosa para a seca (Anchovia clupeoides, Cetengraulis edentulus, Rhinosardinia amazonica, Mugil sp.). O recrutamento foi continuo para Colomesus psittacus e Anchoa hepsetus. Sciades herzbergii apresentou dois picos de recrutamento (estação chuvosa e seca), entretanto Cathorops sp. teve somente um (estação chuvosa). A presença contínua de juvenis nos manguezais sugere que o manejo da pesca em regiões tropicais com vegetação de mangue deveria se direcionar em definir grandes áreas de proteção ao lugar de épocas de defeso.