Using growth rates and otolith shape to identify the population structure of Umbrina canosai (Sciaenidae) from the Southwestern Atlantic

KIKUCHI, EIDI; CARDOSO, LUIS G.; CANEL, DELFINA; TIMI, JUAN T.; HAIMOVICI, MANUEL

MARINE BIOLOGY RESEARCH

TAYLOR & FRANCIS AS

Lugar: Londres; Año: 2021

1745-1000

Identifying populations and establishing the connectivity between neighbouring stocks arecentral issues for the assessment and management of coastal marine fish species. In thispaper, we analysed the population structure of the demersal sciaenid argentine croakerUmbrina canosai, endemic in the warm, temperate southwestern Atantic betweensoutheastern Brazil (SE) and Argentina, by combining two phenotypic techniques: otolithshape analysis and fish growth rate. Three otolith morphotypes were consistently identified,one in the northern latitudinal range in SE, and two in the southern range of the speciesfrom southern Brazil to Argentina. Two stocks with differences in growth rate wereidentified, one with a significantly smaller asymptotic length in the northern range (L∞=340.08; k = 0.267; t0 = −2.177) and the second in the southern range (L∞= 425.08; k = 0.236;t0 = −2.46), where no growth differences were observed between fishes with the two otolithmorphotypes. Although genetically U. canosai can be considered to form a single panmicticpopulation, growth and otolith shape indicate that there are two different stocks, one insoutheastern Brazil and another in the southern distribution, confirming previousparasitological studies. The difference in otolith morphotypes in the southern rangesuggests that two subpopulations share the same reproductive grounds, although probablyfeed in different locations.