Mixed-stock and discriminant models use for assessing recruitment sources of estuarine fish populations in La Plata Basin (South America)

AVIGLIANO, ESTEBAN; JORGE PISONERO; NEREA BORDEL; DOMÁNICO, ALEJANDRO; ALEJANDRA VANINA VOLPEDO

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2019

0025-3154

The objective of thisstudy was to identify potential recruitment sources of Prochilodus lineatus from freshwater areas (Paraná andUruguay rivers) to estuarine population of the Río de la Plata Estuary (LaPlata Basin, South America), considering young (age-1) and adult (age-7) fish. LA-ICP-MS chemical analysis of the otolith core (nineelement:Ca ratios) of unknown mixed sample from Río de la Plata Estuary (2011and 2017) was compared with a young-of-year baseline data set (same cohort) andclassified into freshwater nurseries (Paraná or Uruguay river) by using maximum classification-likelihood models(MLE and MCL) and quadratic discriminant analysis (QDA). Considering thethree models used, the Uruguay River was the most important contributor forboth young and adult populations. The young population (2011) was highly mixedwith contributions between 31.7 to 68.3 %, while the degree of mixing was foundto decrease in 2017 (adult fish) from 97.1 to 100 %. The three employed methodsshowed comparable estimates, however, the QDA showed a high similarity with theMCL model, suggesting sensitivity to evaluate small contributions, unlike theMLE method. Our results show the potential application of maximum likelihoodmixture models and QDA for determining the relative importance of recruitmentsources of fish in estuarine waters of the La Plata Basin.