Does retention or exportation occur in the larvae of the mud shrimp Upogebia vasquezi (Decapoda, Gebiidea)? Implications for the reproductive strategy of the species on the Amazon coast

Abstract

We investigated the effects of eight different levels of salinity (0–35) on the larval development of Upogebia vasquezi, while the abundance of the larvae within the Marapanim estuary on the Amazon Coast was verified through the monthly collection of specimens between August 2006 and July 2007. This species reproduces year-round on the Amazon Coast, which is subjected to strong seasonal fluctuations in salinity due to the local precipitation regime. Upogebia vasquezi larvae developed optimally in salinity close to that of seawater (20–35), while low salinities (0, 5, and 10) did not support the survival of the larvae. Only zoeal stages I, II, and III were captured in the field and were more abundant at the higher end of the salinity gradient, in the areas closest to the adjacent coastal waters. Data from both the laboratory and the field data emphasized the low survival potential of the larvae in low salinities, and increased survival and improved development in more saline water. These results support the hypothesis that U. vasquezi undergo development on the shelf, and also suggest the possibility of an ontogenetic migration toward to adjacent coastal areas during early larval stages, as observed in other decapod species around the world.