“Morphometric and genetic assessment of Cynoscion guatucupa population structure from Buenos Aires coast, Argentine Sea”.

DAVID E. SABADIN; GONZÁLEZ CASTRO, M.; IUDICA, C.; DÍAZ DE ASTARLOA, J. M. AND PEDRO J. FERNÁNDEZ IRIARTE.

REVISTA DE BIOLOGIA MARINA Y OCEANOGRAFIA

INST OCEANOLOGIA

Lugar: Valparaíso, Chile.; Año: 2010 vol. 45

0717-3326

To understand the ecological and evolutionary processes affecting biodiversity of marine species it is necessary to know the spatial and temporal scales of phenotypic and genetic variation, as they provide the explanatory framework for the sustainable conservation of fish populations. The striped weakfish Cynoscion guatucupa is a coastal demersal sciaenid found in part of the continental shelf from Rio de Janeiro (Brazil) up to 43° S in Chubut province (Argentina). The aim of the present work was to analyse morphometric and microsatellite loci variation of the striped weakfish, of two feeding and spawning grounds in the coastal area of Buenos Aires province (Samborombón Bay and El Rincón zone). The geometric characterization of the body shape proved to be distinctly different between fishing sites. The individuals from Samborombón Bay exhibited greater height at the middle part of the body, while those from El Rincón presented greater length and lesser height of the caudal fin. The fact that both sites presented significant excess of homozygotes was ascribed to the possibility that the spawning episodes were either spatial or temporally structured. AMOVA showed that the main source of genetic variation was within the population (99%) rather than across it (1%). Likewise, low differentiation (Fst = 0,0109) was observed between both fishing sites, although a significant heterogeneity was detected in allelic frequencies. The striped weakfish inhabiting the coastal areas of Buenos Aires province would exhibit two management units (stocks) in agreement with other fishes studied in both areas.