Composition of decapod larvae in a northeastern Brazilian estuarine inlet over a full tidal cycle

Abstract

ABSTRACT. Composition changes of decapod larvae in a neotropical estuarine inlet (Catuama inlet, northeast Brazilian coast) were studied in a complete tidal cycle in August 2001. Sampling was performed at three stations at two or three depth levels that were located along a transect across the inlet. The collections were performed in 3 h intervals under a neap tide regime. Samples were taken with a pump and the water was filtered through 300 μm plankton net. 27 planktonic decapod taxa were identified, which included the first larval stages of the coastal and oceanic shrimps Lucifer faxoni and Acetes americanus, besides larvae of the estuarine and coastal decapods Pinnixa spp., Uca spp., Petrolisthes armatus, Upogebia spp. and Alpheidae, which were the most frequent taxa. All of the planktonic larval stages were observed for most of the decapods, suggesting that the probable exportation from the estuary is to the inner adjacent shelf area, instead of the outer oceanic area. Keywords: decapod larvae, meroplankton, tidal changes, neotropical estuary, northeastern Brazil.Composición de larvas de decápodos en la desembocadura de un estuario del noreste brasileño durante un ciclo completo de marea RESUMEN. Se analizaron los cambios en la composición de las larvas de decápodos en la desembocadura de un estuario neotropical durante un ciclo completo de marea en agosto de 2001. Las colectas se realizaron en 3 estaciones, en dos o tres profundidades, localizadas en una transecta interior. Los muestreos se realizaron a intervalos de 3 h durante la marea de cuadratura. Las muestras se colectaron con una bomba y se filtraron a través de una red de plancton (300 μm). Se identificaron 27 taxa de larvas de decápodos, incluyendo el primer estadio larval de los camarones costeros y oceánicos Lucifer faxoni y Acetes americanus, seguidos de las larvas de los decápodos estuarinos y costeros Pinnixa spp., Uca spp., Petrolisthes armatus, Upogebia spp. y Alpheidae, que fueron los taxa más frecuentes. Se observaron todos de los estadios larvales de la mayoría de los decápodos, lo que sugiere que probablemente la exportación del estuario es hacia el área interior de la plataforma adyacente, en vez de hacia el área oceánica exterior. Palabras clave: larvas de decápodos, meroplancton, cambios de marea, estuario neotropical, noreste de Brasil.

Phylogeography of Petrolisthes armatus, an invasive species with low dispersal ability

“…Females of Pacific P. armatus release larvae synchronously near the times of nocturnal high tides 35 , probably as result of predation pressure by visual predators 36 . The larvae may use vertical migrations in order to be retained in estuaries 37 – 39 . Sexual maturity is reached in about a month after settlement.…”