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 E; PISONERO, J.,; SEBASTIAN SANCHEZ,; DOMÁNICO, ALEJANDRO; A.V. VOLPEDO.

RIVER RESEARCH AND APPLICATIONS

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2018 p. 1 - 10

1535-1459

Otolith fingerprints have been developed forstudies of fish stock composition in freshwater systems. In this context, LaPlata Basin is after Amazon, the second largest fluvial-marine system of SouthAmerica, where Prochilodus lineatus isthe most important fishery resource. Despite the basin importance, estimationof mixed 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´s core microchemistry, considering two groups: subadult (2 years) andadult (4 years). Estimates were made using two maximum likelihood methods.Chemical composition of young-of-year fish caught in nursery areas in 2010 wasused as baseline of the models, while chemical composition of the core ofsubadult and adult otoliths was used as sample of unknown origin. Resultssuggest that the subadult stock from Paraná was not mixed (contribution~100%),while the stock from 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 both nursery areas to the Paraná and Uruguay stocks variedbetween 14.8±4.18 and 85.2±4.18%, respectively. The potential application ofotolith fingerprints and maximum likelihood mixture models is here highlighted fordetermining the relative importance of recruitment sources of fish in the LaPlata Basin.