Variation of Mitochondrial Control Region Sequences of Steller Sea Lions: The Three-Stock Hypothesis

Abstract

Sequence variation of a 238 bp segment of the mitochondrial control region was analyzed for 1,568 Steller sea lions (2.8% of the estimated species population) sampled from 50 rookeries representing nearly every locality at which Steller sea lions are known to breed in significant numbers. Haplotype diversity (H = 0.9164 ± 0.0035) was high and nucleotide diversity (π = 0.00967 ± 0.00586) was moderate. No evidence was observed for significant genetic bottleneck effects. Rookeries were grouped into regions and stocks to examine structure at different spatial scales. F-and Φ-statistics were computed for all pairwise comparisons of rookeries, regions and stocks. Significant

Mitochondrial control region haplotypes of the South American sea lion Otaria flavescens (Shaw, 1800)

“…High levels of haplotype diversity (h = 93%) were reported for E. jubatus sampled in Alaska after analysis of 531 bp of the mtDNA control region (14). Also, 91% haplotype diversity was reported for E. jubatus individuals sampled in the North Pacific and Bering Sea, after analysis of 238 bp of the mtDNA control region (15). For Phoca vitulina from the North Pacific, a haplotype diversity of 97% was observed after analysis of 435 bp of the mtDNA control region (16).…”

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

“…For those pinniped species that breed on land (i.e., non-ice breeders and including all otariids or eared seals), most display typical mammalian male-biased dispersal. Females are more likely to remain within their natal group and show sufficiently strong philopatry to create significant matrilineal substructure detectable with mitochondrial DNA (mtDNA) markers (Andersen et al, 1998;Burg et al, 1999;Hoelzel et al, 2001;Baker et al, 2005;Gonzalez-Suarez et al, 2009). However, when biparentally inherited nuclear markers have been used, while structuring may persist, overall the patterns are weaker, indicating that females are usually more philopatric than males (Andersen et al, 1998;Burg et al, 1999;Hoelzel et al, 2001;Hoffman et al, 2006;Gonzalez-Suarez et al, 2009).…”

Environmental and biological factors influencing maternal attendance patterns of Steller sea lions (Eumetopias jubatus) in Russia

“…All bathymetry data were obtained from the global 30-arc-second General Bathymetric Chart of the Oceans (GEBCO) Digital Atlas (General Bathymetric Chart of the Oceans 2003) and imported into the R statistical programming package (R Development Core Team 2009) using the RNetCDF package (Michna 2006). Of the roughly 16,000 sea lions in Russia, approximately 8,000 reproduce on the Kuril Islands (Burkanov and Loughlin 2005) and are considered to belong to the Asian stock (Baker et al 2005). The Kuril Islands population experienced a 70% range-wide decline from a peak of .20,000 individuals in the 1960s to a nadir of about 6,000 in the 1990s but has since been recovering steadily (Burkanov and Loughlin 2005 ; Fig.…”

“…The sea lions populating these islands belong to the western stock (Baker et al 2005) but travel regularly to the eastern coast of Kamchatka (Burkanov and Calkins 2008;Burkanov and Loughlin 2005). Sea lions reproduce on Medny Island (52uN, 168uE), the smaller of the 2 islands, on a strip of gravel and rocky beach at the southeastern tip of the island.…”

“…Recent genetic evidence together with branded animal resighting patterns indicate that the Kamchatka, Kuril, Sakhalin, and Sea of Okhotsk populations constitute a separate Asian stock, and the Commander Islands population aligns with the western stock (Baker et al 2005). Population trends in the Commander Islands have mirrored western population declines, with an estimated 86% decline since 1977 (Burkanov and Loughlin 2005;Burkanov et al 1991).…”