ANTARCTICA’S BLUE WHALE ARE MADE UP OF THREE POPULATIONS
Antarctica blue whales (Balaenoptera musculus intermedia) a critically endangered subspecies and the largest extant animal, are made up of three populations, according to a recent study of Australian researches based in a new DNA analysis, the results are published in Scientific Reports.
Researchers suspect that the three populations go their separate ways when they head north to breed – presumably heading into the three major Southern Hemisphere ocean basins: the South Pacific, South Atlantic and Indian Oceans. Individuals from the three populations occur together throughout the Antarctic, although possibly in different proportions in different areas. This is probably because the blue whales need to rove long distances around Antarctica to find the massive amounts of krill that make up their sole food source.
Scientists urge that future research should invest in locating the breeding grounds and migratory routes of Antarctic blue whales through satellite telemetry to confirm their population structure and allow population-level conservation.
Antarctic blue whales reduced in abundance from 239,000 before hunting commenced in the 1904/05 austral summer season to a low of 360 when they were last hunted in the 1972/73 season. The most recent abundance estimate was 2,280 from surveys conducted between the 1992/93 and 2003/04 austral summer. This is only about 1% of pre-exploitation abundance. The subspecies is classified as Critically Endangered in the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.
The blowhole of an Antarctic blue whale by Kylie Owen
- Reference (open access): Attard et al. 2016. Towards population-level conservation in the critically endangered Antarctic blue whale: the number and distribution of their populations Scientific Reports