Figure 2. Population structure of present-day and historical blue whales from North Atlantic A . Map of sampling locations of blue whales B. Principal component analysis (PCA) ten Northwest Atlantic (NWA) blue whales, eight Northeast Atlantic (NEA) blue whales, one Antarctic blue whale, seven fin whales from North Atlantic and two sei whales using LASER. The circled sample represents the blue-fin hybrid historical sample (NWa-CM1) C. PCA of seven NWA blue whales, eight NEA blue whales and one Antarctic blue whale with LASER.D. Maximum likelihood tree using TREEMIX for NE, NW and Antarctic blue whales with two migration edges, considering each individual as a separate population and fin whale as the root. The horizontal branch lengths are proportional to genetic drift along that branch and the scale bar shows ten times the average standard error of the entries in the sample covariance matrix. E. Individual admixture proportions using NGSadmix for a single run from 10 runs of k=2 and k=3 for present-day and historical sample from NWA, NEA and Antarctic). The X-axis displays the proportion of ancestry and the Y-axis displays blue whale samples.