Strontium isotopes (87Sr/86Sr) reveal the life history of freshwater migratory fishes in the La Plata Basin

Strontium isotopes (87Sr/86Sr) were evaluated as a potential method for studying the geographical origin of populations and movements patterns of migratory fish from the La Plata Basin (Paraná, Uruguay and Bermejo Rivers and Río de la Plata Estuary, South America). Surface water samples were collected at 43 sites during austral summer and winter (2018) while, Surubí (Pseudoplatystoma corruscans), Patí (Luciopimelodus pati), dorado (Salminus brasiliensis) and sábalo (Prochilodus lineatus) fishes were collected at seven locations. Water 87Sr/86Sr ratio was analysed by MC‐ICP‐MS (N = 74) and otolith core‐to‐edge 87Sr/86Sr transects (N = 50) were measured by LAfs‐MC‐ICP‐MS. Several water bodies presented significantly different (p