A total of 1018 individuals were screened for 9 microsatellite loci from different feeding grounds within the Northeast Atlantic, namely, West off Iceland (n=903), Spain (n=39), Norway (n=54), West off Greenland (n=9) and East off Canada (n=13) in order to study the temporal and micro- and macrogeographical structure of North Atlantic fin whales (Figure 1; Table 1).