Strontium isotope mapping and its application to study the fish life history (Salminus brasiliensis) in semi-fragmented rivers (La Plata Basin, South America)

AVIGLIANO, ESTEBAN; CHUNG, MING-TSUNG; POUILLY, MARC; HUANG, KUO-FANG; CASALINUOVO, MIGUEL; DOMININO, JAEL; SILVA, NATALIA; SÁNCHEZ, SEBASTIAN; FACETTI, JUAN F.; VOLPEDO, ALEJANDRA V.

FISHERIES RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2023 vol. 265 p. 1 - 10

0165-7836

Salminus brasiliensis is one of the largest and most important commercial and sporting fish species in South America, of which little is known about its habitat use, especially in semi-fragmented rivers. The aims of thisstudy were to expand the water 87Sr/86Sr baseline of the La Plata Basin, and to study the migratory patterns ofS. brasiliensis from Paran´a dam-free stretch and a representative tributary semi-fragmented using otolith isotopicchemistry. Water samples were collected at 10 sites on the upper Paran´a River and two sites on the middle andlower Carcara˜n´a Basin (tributary of the lower Paran´a River). Fourteen fish were caught in the upper Paran´a Riverand 13 in two sites of the middle and lower Carcara˜n´a Basin. 87Sr/86Sr was measured in water and otolith coreto-edge transect by MC-ICPMS and LA-MC-ICPMS, respectively. Water results were incorporated into a datasetwith 53 other sampling points from the La Plata Basin and subjected to a cluster analysis, which resulted in ninedifferentiable chemical signatures. Discriminant analysis confirmed the presence of at least eight contrastingisotopic signals. Based on the otolith core 87Sr/86Sr, four individuals from the upper Paran´a River were classifiedas originating from Paraguay sub-basin, while the rest were assigned to Paran´a River. All fish from the Carcara˜n´asub-basin were classified as originating from the Paran´a River, except two individuals which were assigned to theCarcarana sub-basin. Results indicated that the fish run up the Carcara˜n´a sub-basin overcoming up to three openspillways, and could live there for years and even reproduce. However, the Paran´a River had the largestcontribution to the fish caught in both the upper Paran´a River and the Carcarana sub-basin.