Estructura de la Comunidad Bentónica y Predación de la Corvina Rubia (Micropogonias furnieri, Sciaenidae) en el Estuario del Río de la Plata, Argentina-Uruguay

GIBERTO, D.A.; BREMEC, C.S.; ACHA, E. M.; MIANZAN, H.

San Andrés, Colombia

Congreso; IX Congreso Latinoamericano sobre Ciencias del Mar (COLACMAR); 2001

Benthic Community Structure and Predation of the Withemouth Croaker (Micropogonias furnieri , Sciaenidae) in the Río the la Plata Estuary, Argentina-Uruguay. This study deals with the spatial distribution of macrobenthic communities (biomass and abundance) and their relation with the diet of the withemouth croaker (Micropogonias furnieri) in the Río de la Plata estuary. The benthic invertebrates were caught with an epibenthic dregde (41 samples). It was applied multivariate analysis (cluster, MDS) and SIMPER test. An estuarine zone was established, with muddy sediments and a wide range of salinity, characterized by higher abundance and biomass of fauna and lower diversity (H’), dominated by the deposit-feeding bivalve Mactra isabelleana; and a marine zone, with sandy-gravel sediments and higher and less variable salinity values, dominated by detritivorous crustaceans and filter-feeding molluscs, with highervalues of diversity (H’). We analized 258 gut contents of withemouth croaker (5-70 cm total length,TL) and calculated an index of relative importance of prey (IRI). M. isabelleana was the main prey of withemouth croaker > 10 cm TL (%IRI=99.68), juveniles <10 cm TL preyed mostly on Mysidacea (%IRI=94.56). The major presence of deposit-feeders at the estuarine zone could be related with higher particulate organic matter present at the estuary. It is proposed that the estuary of the Río de la Plata is characterized by short food webs, based on the organical detritus. M. isabelleana would represent a linkage between organical detritus and M. furnieri.(Micropogonias furnieri , Sciaenidae) in the Río the la Plata Estuary, Argentina-Uruguay. This study deals with the spatial distribution of macrobenthic communities (biomass and abundance) and their relation with the diet of the withemouth croaker (Micropogonias furnieri) in the Río de la Plata estuary. The benthic invertebrates were caught with an epibenthic dregde (41 samples). It was applied multivariate analysis (cluster, MDS) and SIMPER test. An estuarine zone was established, with muddy sediments and a wide range of salinity, characterized by higher abundance and biomass of fauna and lower diversity (H’), dominated by the deposit-feeding bivalve Mactra isabelleana; and a marine zone, with sandy-gravel sediments and higher and less variable salinity values, dominated by detritivorous crustaceans and filter-feeding molluscs, with highervalues of diversity (H’). We analized 258 gut contents of withemouth croaker (5-70 cm total length,TL) and calculated an index of relative importance of prey (IRI). M. isabelleana was the main prey of withemouth croaker > 10 cm TL (%IRI=99.68), juveniles <10 cm TL preyed mostly on Mysidacea (%IRI=94.56). The major presence of deposit-feeders at the estuarine zone could be related with higher particulate organic matter present at the estuary. It is proposed that the estuary of the Río de la Plata is characterized by short food webs, based on the organical detritus. M. isabelleana would represent a linkage between organical detritus and M. furnieri.