Estimating contributions from nursery areas to fish stocks in freshwater systems using otolith fingerprints: the case of the Streaked prochilod in the La Plata Basin (South America)

AVIGLIANO, ESTEBAN; JORGE PISONERO; SÁNCHEZ, SEBASTIÁN; ALEJANDRO DOMANICO; ALEJANDRA VANINA VOLPEDO

RIVER RESEARCH AND APPLICATIONS

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2018 vol. 34 p. 863 - 872

1535-1459

Stock composition studies using otolith fingerprints havescarcely been developed in freshwatersystems. In this context, the secondlargest fluvial-marine system of SouthAmerica, where Prochilodus lineatus isthemost important fishery resource. Despite the basin importance, estimationofmixed stock compositionhas not been explored yet. In this paper,the contribution of the two mainnursery areas to two fishing stocks(Uruguay and Paraná rivers) of P. lineatus was evaluated usingotolith´score microchemistry, considering two groups: subadult (2 years) andadult (4years). Estimates were made using two maximum likelihood methods.Chemicalcomposition of young-of-year fish caught in nursery areas in 2010 wasused asbaseline of the models, while chemical composition of the core ofsubadult andadult otoliths was used as sample of unknown origin. Resultssuggest that thesubadult stock from Paraná was not mixed (contribution~100%),while the stockfrom Uruguay had a contribution from the Paraná nursery(1.5±1.2‒17.9±3.96%).For the adults, the degree of mixing increased and thecontribution from bothnursery areas to the Paraná and Uruguay stocks variedbetween 14.8±4.18 and85.2±4.18%, respectively. The potential application ofotolith fingerprints andmaximum likelihood mixture models is here highlighted fordetermining therelative importance of recruitment sources of fish in the LaPlata Basin.Because the contributions of the different nursery areas sharedamong severalnations in turn affect the composition of internationally sharedstocks,comprehensive management agreements at the basin level are necessary.