Range-wide phylogeography of South American sea lion (Otaria flavescens) reveals an extremely ancient female philopatry and an asymmetric male gene flow between Pacific and Atlantic oceans

FRAGA LÚCIA D.; GEHARA MARCELO C. M. ; MARCELO H. CASSINI; HECTOR PÁVEZ; OLIVEIRA LARISSA ROSA DE; JUAN IGNACIO TÚNEZ; LOIZAGA DE CASTRO, ROCÍO; LOPES FERNANDO ; SUSANA CÁRDENAS; CARLOS OLAVARRÍA; PATRICIA MAJLUF; GARCÍA NÉSTOR ANÍBAL; MARIA JOSE PÉREZ-ALVAREZ; MARITZA SEPÚLVEDA; CRESPO ENRIQUE ALBERTO; RENATO QUIÑONES; RUS HOELZEL; SANDRO L. BONATTO; VICTOR HUGO VALIATI; PAULO HENRIQUE OTT

Valparaiso

Congreso; 17° Reunión de Trabajo de Especialistas en Mamíferos Acuáticos de América del Sur y XI Congreso de la Solamac; 2016

Sociedad Latinoamericana para el estudio de los Mamíferos Acuáticos de América del Sur

AbstractAimThe South American sea lion (Otaria flavescens) is widely distributed along the southern Atlantic and the Pacific coasts of South Americawith a history of significant commercial exploitation. We aimed to evaluate the population genetic structure and the evolutionary history of South American sealions along its distribution by analyses of mitochondrial DNA (mtDNA) and nuclear microsatellites.Location Atlantic and Pacific coasts of South America.MethodsWe analyzed 147 sequences of mtDNAcontrol region and genotyped 111 individuals of South American sea lion for 10 microsatellite loci, that represent six populations (11 localities) that cover the entire distribution of the species (Peru, Northern Chile, Southern Chile, Uruguay (Brazil), Argentina and Falkland (Malvinas) Islands).Results The mtDNA phylogeny shows the haplotypes from the two oceans comprise two very divergent (>1 million years) clades, suggesting a long period of no inter-oceanic female gene flow. While Bayesian analysis of bi-parental genetic diversity suggested inter-oceanic gene flow mediated by males, it still supportedsignificant (but less pronounced than mitochondrial) genetic structure between Pacific and Atlantic populations. A similar higher male migration rates were found in the intra-oceanic population comparisons, again supporting very high female phylopatry in the species. Demographic analyses shown that populations from both oceans went through a significant population expansion ~10,000 years ago, suggesting a very similar influence of historical environmental factors, such as the last glacial cycle, on both regions. Main Conclusions Our results support the proposition that the Pacific and Atlantic populations of the South American sea lion should be considered distinct evolutionarily significant units, with at least two managements units in each ocean.