Population structure of mud flounder Paralichthys orbignyanus from the south‐western Atlantic Ocean

FAINBURG, LEANDRO; SABADIN, DAVID; DÍAZ DE ASTARLOA, JUAN MARTÍN; FERNÁNDEZ IRIARTE, PEDRO

JOURNAL OF FISH BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2022 p. 1 - 10

0022-1112

The mud flounder Paralichthys orbignyanus (Pleuronectiformes, Paralichthyidae)inhabits shallow waters of low salinities and mud bottoms in the temperate marinecoastal regions of the Bonaerensean Ecoregion of the Argentinean BiogeographicProvince in the south-western Atlantic Ocean. Specimens of P. orbignyanus were collected from Lagoa dos Patos (LDP) (southern Brazil), Mar Chiquita (MCH) and Marisol(MAR) both located in Buenos Aires (Argentina), and San Antonio Oeste (SAO) in theSan Matías Gulf, Rio Negro (Argentina). A fragment of the mitochondrial DNA of theControl Region and seven microsatellite loci were characterized. In the ControlRegion, P. orbignyanus showed high variability, low nucleotide diversity, mild population expansion and a coalescence time of 35,000 years before the present. Floundersprovided evidence of a genetic structure between the sampling sites LDP, MCH,MAR vs. SAO. On the other hand, P. orbignyanus displayed a lower to moderate contemporary genetic structure among all samples except between LDP and MCH. Withno evidence of isolation by distance, this analysis supports a model of limited geneflow that is likely to be associated with a consistent larvae retention in all samplingsites. In addition, the present connectivity is ascribed to a lower migration processfrom SAO in the San Matías Gulf congruent with the prevailing littoral drift.