Fluvio-marine travelers from South America: cyclic amphidromy and freshwater residency, typical behaviors in Genidens barbus inferred by otolith chemistry

MATHIEU LEISEN; GONZALO VELASCO; ESTEBAN AVIGLIANO; ALEJANDRA VANINA VOLPEDO; BARBARA CARVALHO; FERNANDO BARRA PANTOJA ; RURIK ROMERO; MARCELO VIANNA

FISHERIES RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 193 p. 184 - 194

0165-7836

Catfish Genidensbarbus is a commercially fished species from the south-western Atlantic Ocean. Overfishing of this speciesduring the last few years has caused a collapse of fisheries and in turn has ledto a ban of its exploitation. In order to identify the migratory patterns of thisspecies in four migration corridors from South America, we determined the Sr:Caand Ba:Ca ratios in otoliths, by Laser Ablation Inductively Coupled Plasma MassSpectrometry (LA-ICPMS). Sr:Ca and Ba:Ca ratios range between 0.90 and 9.83mmol/mol (mean ± standard deviation: 3.86 ± 1.05 mmol/mol) and between 0.00013and 0.10 mmol/mol (mean ± SD: 0.0094 ± 0.0160 mmol/mol), respectively. Threetypes of amphidromous and cyclical (annual) patterns that include the use offreshwater, estuarine and marine environments are detected. Resident freshwaterfish (6.5%) are found only in Patos Lagoon. Depending on the study site,between 18?45% of the analyzed fish population were spawned in freshwater,while the rest were spawned in estuarine waters. The change-point analysis showsa positive correlation between changes in the transects of Sr:Ca and Ba:Ca ratios(r=0.63, p=0.0001), whereas the Kruskal-Wallistest shows no significant differences in the number of changes in transects of theSr:Ca ratio between sampling sites (H = 2.1, p = 0.53). Only for Patos Lagoon the analyses show a significantly higher numberof changes for the Ba:Ca ratio (H = 9.1, p = 0.03). The data indicate that the average number of movements amongenvironments is similar between the four corridors. The number of changes of theBa:Ca ratio appears to be higher and more variable in relation to the Sr:Caratio, indicating that the former could be more sensitive to environmentalchanges. In conclusion, this work describes for the first time, annualamphidromous migrations and dependence onfreshwater for different fluvial-marine systems. The understanding of thehabitat use will help design species and estuarine-specific management actionswith the ultimate goal of recovering fisheries.