FISHES FROM THE RÍO DE LA PLATA, THE ESTUARY AND ADJACENT SHELF AND SLOPE

M. GARCÍA, A. JAUREGIZAR, H. LÓPEZ, A. MIQUELARENA, R. MENNI, L. PROTOGINO & C. GARCÍA

Environmental Assessment and Planning of a Traunsboundary Fluvio-Marine Ecosystem: the Río de la Plata and its Maritime Front CHAPTER 9. Fish Diversity of the Río de la Plata and its Maritime Front

Springer Verlag

Lugar: New York; Año: 2011;

ABSTRACTThe Río de La Plata has been traditionally divided in three zones, internal,intermediate and external, with clear geographic limits and distinctiveenvironmental traits. The ichthyofauna is composed by freshwater, brackish andmarine species which occurs along a longitudinal ecological gradient. Distributionof species throughout this gradient allows us to recognize two defined areas: aRiverine area characterized by a freshwater fish assemblage and an Estuarinearea with an assemblage composed by freshwater, brackish water and marinefishes, including migrant species which use this space as nursery area. Followingthe gradient to the southwest we establish other two areas; one adjacent to the Ríode la Plata (the Shelf area) and a following one (the Slope area), both with more2stable environmental and only marine fishes. Temperature and bottom salinitywere identified as the determinant factors of these associations. Along thegradient, changes in the food energy source from benthic production or detritus tophytoplankton and zooplankton evidence their importance in structuring demersalfish communities. Analysis of population genetic structure analyses of commercialimportant fishes shows the existence of different genetic stocks which may beconsidered as management units in sustainable fisheries.