The discovery of three genetically different groups of Antarctic blue whales by Flinders University researchers shows that the whales migrate into three different oceans because of different human impacts like pollution or shipping noise that affect their population. The study published in the journal Scientific Reports in March 8 presents that each whale group needs different conservation efforts to help them recover from their critically endangered status.

To determine which whales are part of the same population, the researchers analysed 142 samples of blue whale skin and blubber that were collected by the International Whaling Commission (IWC). Researcher Catherine Attard explains that one population might migrate to South Pacific, one to South Atlantic and one to the Indian Ocean to breed.

Photo of Antarctic blue whale in Antarctica. Photo by Paula Olson/IWC

Photo of Antarctic blue whale in Antarctica. Photo by Paula Olson/IWC

“What really surprised us was that these populations co-occupy areas throughout the Antarctic, rather than occupying discrete areas like their humpback whale cousins,” adds Attard. “The blue whale populations likely move around the Antarctic to locate their sole food source, krill. Blue whales require high densities of krill to support their massive energy requirements.”

The researchers added that the animal population has now been reduced to 360 whales from 239,000 after hundreds of thousands of blue whales were killed by whaling in the 20th century. However, despite their massive size, blue whales are still difficult to find, complicating ongoing research about them.

Researcher Luciana Möller asserts that more studies are needed to fully gather the information, to monitor these animals, and to implement conservation methods. The next step in the research is to confirm the whale population structure and get more data on where blue whales travel.

This could be accomplished by continuing the vessel surveys in the Antarctic and satellite tagging the whales to reveal their migratory destinations. Attard notes that the current efforts to save these animals have allowed the recovery of a few thousand, a number that stands for less than one percent of the whole whale population.