Variation in body size of ringed seals (Pusa hispida hispida) across the circumpolar Arctic: evidence of morphs, ecotypes or simply extreme plasticity?

The ringed seal is a small phocid that has northern circumpolar distribution. It long been recognized body size variable in seals, and it suggested ecotypes differ exist. This study explores patterns of (length girth) age-at-maturity across most the Arctic subspecies’ range using morphometric data from 35 sites. Asymptotic lengths varied 113 to 151 cm, with sites falling into five distinct clusters (for each sex). Age-at-maturity ranged 3.1 7.4 years, had early ages sexual maturity generally having length-at-maturity final length. sexes differed length at some sites, but not consistent pattern dimorphism. largest seals occurred western Greenland eastern Canada, smallest Alaska White Sea. Latitudinal trends only within Canadian Arctic. Girth (with season accounted for) was also highly showed no notable spatial pattern; males tended be more rotund than females. Genetic studies are needed, starting “giants” Kangia (Greenland) Canada determine whether they genetically ecotypes. Additional research needed understand ecological linkages drive significant regional differences were confirmed this study, their implications respect potential adaptation climate change.