Mitochondrial and microsatellite assessment of population structure of South American sea lion (Otaria flavescens) in the Southwestern Atlantic Ocean

Feijoo, Matías; Lessa, Enrique P.; Castro, Rocío Loizaga de; Crespo, Enrique A.

doi:10.1007/s00227-011-1697-4

Cited by 40 publications

(49 citation statements)

References 65 publications

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“…Differentiation between South Australian and Western Australian colonies is not surprising considering the distance (>2200 km) between these two regions. However in comparison to other pinniped studies conducted at similar or larger spatial scales the F ST values reported here between these two regions were higher (Hoelzel et al, 2001;Palo et al, 2001;Coltman et al, 2007;Graves et al, 2009;Andersen et al, 2011;Feijoo et al, 2011). Strong genetic partitioning between South Australian and West Australian colonies is also evident with mtDNA data (significant pairwise ST values ranged from 0.83 to 0.94, Campbell et al, 2008).…”

Section: Genetic Diversity and Differentiationcontrasting

confidence: 56%

The Limits of Dispersal: Fine Scale Spatial Genetic Structure in Australian Sea Lions

et al. 2016

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Describing patterns of connectivity throughout a species range is critical to conservation management. In common with other mammals, pinnipeds typically display male-biased dispersal. Earlier studies using mitochondrial DNA showed that the endangered Australian sea lion (Neophoca cinerea) exhibits extreme matrilineal structure throughout its range. If male dispersal were similarly restricted, most breeding colonies may not receive sufficient levels of new genetic variation to buffer against risks associated with inbreeding and environmental change. To address these concerns we used 16 microsatellite loci to obtain a more highly resolving measure of genetic structure among colonies and determine whether dispersal is male-biased. We found that both male and female Australian sea lions are highly philopatric with limited dispersal. Within those constraints, when animals disperse between close colonies (<110 km) there is a tendency for males to move further than females. Our findings are intriguing considering the dispersal potential of Australian sea lions and the unique asynchronous breeding opportunities that might be expected to provide an incentive for male reproductive movements between geographically close colonies.

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Section: Genetic Diversity and Differentiationcontrasting

confidence: 56%

The Limits of Dispersal: Fine Scale Spatial Genetic Structure in Australian Sea Lions

et al. 2016

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“…The first genetic study of the species with allozymes did not show structure evidence between the colonies of Argentina and Uruguay within Atlantic coast [12]. However, most of the mitochondrial analyses performed to date are somewhat in line with the morphological results, showing strong and significant differentiation (high fixation index) with almost total absence of haplotype sharing between Pacific and Atlantic localities [8,13–16], although the most recent and extensive study that included sequences from Chile and Falkland Islands found two shared haplotypes between these areas [14]. These mtDNA differences have led some authors to propose two evolutionarily significant units (ESUs), one in each ocean [8,15,16].…”

Section: Introductionmentioning

confidence: 94%

Ancient female philopatry, asymmetric male gene flow, and synchronous population expansion support the influence of climatic oscillations on the evolution of South American sea lion (Otaria flavescens)

et al. 2017

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The South American sea lion (Otaria flavescens) is widely distributed along the southern Atlantic and Pacific coasts of South America with a history of significant commercial exploitation. We aimed to evaluate the population genetic structure and the evolutionary history of South American sea lion along its distribution by analyses of mitochondrial DNA (mtDNA) and 10 nuclear microsatellites loci. We analyzed 147 sequences of mtDNA control region and genotyped 111 individuals of South American sea lion for 10 microsatellite loci, representing six populations (Peru, Northern Chile, Southern Chile, Uruguay (Brazil), Argentina and Falkland (Malvinas) Islands) and covering the entire distribution of the species. The mtDNA phylogeny shows that haplotypes from the two oceans comprise two very divergent clades as observed in previous studies, suggesting a long period (>1 million years) of low inter-oceanic female gene flow. Bayesian analysis of bi-parental genetic diversity supports significant (but less pronounced than mitochondrial) genetic structure between Pacific and Atlantic populations, although also suggested some inter-oceanic gene flow mediated by males. Higher male migration rates were found in the intra-oceanic population comparisons, supporting very high female philopatry in the species. Demographic analyses showed that populations from both oceans went through a large population expansion ~10,000 years ago, suggesting a very similar influence of historical environmental factors, such as the last glacial cycle, on both regions. 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.

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“…Genetic analysis suggests that South American sea lions have a strong female philopatry to breeding areas and gene flow is mediated by male dispersion along the Atlantic coast (Feijoo et al, 2011). Breeding colonies analysed in this study had no significant genetic differences from central Patagonia rookeries (Túnez et al, 2010;Feijoo et al, 2011). This fact leads our estimated Ne to be underestimated.…”

Section: Discussionmentioning

confidence: 63%

“…The northem Patagonia sea lion population may have been as small as 5000 animals (Koen Alonso and Yodzis, 2005;Grandi, 2010). However, microsatellite analysis showed no genetic bottleneck due to the severe reduction in population size (Feijoo et al, 2011). This result could be related to the rapid re-distribution of genetic variability among colonies due to gene flow possibly mediated by males as well the overlap of generations (Feijoo et al, 2011).…”

Section: Discussionmentioning

confidence: 79%

A hunted population in recovery: Effective population size for South American sea lions from Patagonia

et al. 2012

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Effective population size {Ne) is a parameter of central importance in evolutionary biology and conservation. Factors such as unequal sex ratios of breeding individuals, pedodic fluctuation in population size and vadance in reproductive success can affect the Ne in general. At present. South Amedcan sea lions, Otariafiavescens, from northem Patagonia, Argentina, belongs to one of the several populations that are recovedng from overhunting which occurred in the early 20* century. Here, we present the estimate of Ne for this population that takes into account the effects of their polygynous mating system and vadation in population size through time. The resultant overall A^^' s were 4171 ± 2450 or 4745 ± 2681 breeding animals depending on the inclusion of pedpheral adult males. The estimated Ne's are not cdtical, because they are close to the average mean minimum viable population for vertebrates (5000 breeding adults). Even though the northem Patagonian population of O. ßavescens is increasing its abundance is stiU far below its histodcal numbers. The Ne estimated should be considered the minimum range to be maintained, especially in light of bycatch related to fishery interactions along the Patagonian coast. We emphasise the importance of estimating A^^ for future management plans of the species within different populations.

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Mitochondrial and microsatellite assessment of population structure of South American sea lion (Otaria flavescens) in the Southwestern Atlantic Ocean

Cited by 40 publications

References 65 publications

The Limits of Dispersal: Fine Scale Spatial Genetic Structure in Australian Sea Lions

The Limits of Dispersal: Fine Scale Spatial Genetic Structure in Australian Sea Lions

Ancient female philopatry, asymmetric male gene flow, and synchronous population expansion support the influence of climatic oscillations on the evolution of South American sea lion (Otaria flavescens)

A hunted population in recovery: Effective population size for South American sea lions from Patagonia

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