Ontogenetic habitat preferences of whitemouth croaker Micropogonias furnieri in coastal waters under influence of Río de la Plata, South America

JAUREGUIZAR, A. J.; DOGLIOTTI, A.I.; GUERRERO, R. A.; LASTA, C. A.

Mar del Plata

Congreso; Coastal and Estuarine Research Federation (CERF); 2012

The Rio de la Plata drains the second largest basin in South America after the Amazon River and is considered one of the most turbid rivers in the world, and its mixohaline area has high ecological importance. The aim of this study was to  determine the ontogenetic habitat preferences of M. furnieri in costal waters under the influence of Rio de la Plata, and represents the first attempt to estimate the influence of turbidity. The M. furnieri length-class distribution and its relationship to environmental factors (salinity, temperature, depth, turbidity, vertical stratification, horizontal gradient of salinity and temperature) were evaluated from 86 stations in winter (2004, 2006 years) and 79 stations in spring (2003, 2005 years). The canonical correspondence analyses of fishery research survey data showed that M. furnieri length-size classes were differentially affected by turbidity and salinity in winter, and salinity and depth in spring. In both season, the main spatial difference was between juveniles and adult length size classes, been the juveniles associated to water with lower salinity and depth, and higher turbidity than adult. Within juveniles, the length-size classes showed high environmental segregation related to turbidity in both season, while the adult where only segregated during spring and associated to salinity. The winter variation observed in the turbidity spatial distribution, mainly associated to freshwater discharge and wind pattern, allows explaining the inter-annual difference in the juvenile length-size classes. Therefore, understanding of the environmental conditions present in the evaluation area will lead to a more efficient estimation of M. furnieri abundance trend and its fishery management.