Saved from whaling, blue whales now face threat from global warming, human activities: Study
global warming and other human threats like underwater noise, pollution and disrupted food sources, according to a new stocktake of their population. Researchers found the greatest genetic differences among the blue whale populations in the eastern Pacific, Antarctic subspecies and the pygmy subspecies of the eastern Indian and western Pacific. Blue whales average about 27 metres in length.
Natural selection could be one of the reasons behind these differences, they said.
«Each of these groups need to be conserved to maintain biodiversity in the species, and there are indications that natural selection in different environments contributed to driving genetic differences between the high-level groups,» said Catherine Attard, College of Science and Engineering, Flinders University, Australia. He is the first author of the study published in the journal Animal Conservation.
Using genomic analysis, the researchers found an «unexpected» similarity between the blue whales of the eastern South Pacific and those of the eastern North Pacific, suggesting they were part of the same subspecies, and not separate as they are currently considered.
«Unexpected» because the mammals are thought to have opposite when their populations exist on the either side of the equator, they said.
Further, despite low genetic diversity between the eastern Indian and western Pacific populations, the researchers identified the eastern Indian Ocean, western South Pacific Ocean and potentially western Indian Ocean as «different» populations
