Spatial segregation and connectivity in young and adult stages of Megaleporinus obtusidens inferred from otolith elemental signatures: Implications for management

Abstract

Boga Megaleporinus obtusidens is a teleost fish of economical and sport importance from Río de la Plata Basin (South America). Otolith core and edge elemental ratios (Ba:Ca, Cu:Ca, Li:Ca, Mg:Ca, Mn:Ca, Pb:Ca, Rb:Ca and Sr:Ca) were compared among three sampling areas from the Río de la Plata Basin (Paraná and Uruguay Rivers and Río de la Plata Estuary) to evaluate the applicability of the fingerprint to study segregation and connectivity in young and adult stages. Several ratios were significantly different among sites for otolith core and edge (p < 0.05). PERMANOVA (p < 0.05) and quadratic discriminant function analysis (classification rates: 86.8% and 82.5% for otolith core and edge, respectively) were found to be highly effective in detecting differences in otolith core and edge fingerprints between sampling sites suggesting the existence of spatial segregation in young and adult life stages, respectively. The presence of relatively isolated groups may require the need to manage the stocks separately.