Given how large they are, you would have thought that we would know about all populations of the blue whale, but it would appear not.
A new population has been found living in the Indian ocean. It was discovered, when a researcher off the coast of Madagascar, recorded their song, and it did not match any of the known songs.
Each blue whale have a distinctive song of their own, which allows humans (and other blue whales) to identify grounds. These songs can travel incredible distances through the water, and have been picked up more than 500 miles from where the whale was. What makes this discovery more amazing, is that a significant amount of work has been done in the Indian ocean, and they thought that they had identified each group.
While this new group of blue whales is good news, there is still much protection that is needed for the whales in this region, as many are surprisingly distinct (some being distinct enough to make them a separate species or sub-species). Unfortunately as with other areas, no matter how distinct and different these whales are, they are often severely endangered before we find them.