Larval density of Ucides cordatus (Linnaeus, 1763) and Goniopsis cruentata (Latreille, 1803) in a semiarid estuary, Ceará State

Abstract

The estuarine zooplankton community is potentially limited by the currents, which can export these organisms to the marine environment. Brachyuran species use this movement of water as a survival strategy in the early stages of life. This study aimed to quantify the larval zoea I of crabs Ucides cordatus and Goniopsis cruentata in Jaguaribe River estuary by means of samples taken during the dry season, in July – September of 2007, and during the rainy season, in March – May of 2008, a day before the occurrence of spring tide (new moon). The larvae were collected in the tidal ebb and flow through subsurface horizontal hauls with net 300 μm. During dry season, were found only zoea I of G. cruentata with a density of 148,0 ± 370,7 ind./m³. In the rainy season, we found larvae of both species, with U. cordatus showing a density of 2806,8 ± 11381,8 ind./m³ and G. cruentata, density of 1569,8 ± 5635,9 ind./m³. The highest densities occurred at ebb tide, indicating that the larvae leave the estuary.