Prof Carlos Melecio Carmona Cedillo
Institute of Marine Sciences and Limnology, UNAM, MEXICO
Title: The Ichthyoplancton adundance distribution asociate to geostrophic currents into Grijalva – Usumacinta River Plume
Biography
Biography: Prof Carlos Melecio Carmona Cedillo
Abstract
Analysis of spatial abundance distribution of ichthyoplankton, realted to geostrophic currents into the discharge region of the Gijalva-Usumacinta system rivers. The data was collected at 35 stations infront of Grijalva – Usumacinta rivers discharge area, by the oceanographic survey “PROMEBIO-I”, held from 15 to 18 August 1999. The hydrographic data was obtained by CTD and ichthyoplancton biological data was collected by double oblique tows in three ten meters layers with open-clouse networks of 75 cm diameter in the mouth and 500 ïm of mesh size. The ichthyoplankton was standardized to 100 cubic meters and is reported as number of larvae (no. larvae/100 m3). The geostrophic currents was estimated from temperature and salinity average data in the first 3 layers, using a linear inverse model solved by the finite differences method. From the results it is possible to identify four habitats and two types of fronts: A plume front (permanent), formed by river water discharges, less saline, from the Grijalva-Usumacinta system, and a topographic front (front of shallow seas) associated with the edge of the continental shelf. Maximum number of fish larvae was associated to the front formed by the Grijalva-Usumacinta system and the geostrophic currents are associated with the same pattern.