The blue whale, possibly the largest animal ever to live on Earth, is making a comeback, scientists have said. Data shows that the population of marine mammal in the Southern Hemisphere have increased from a few hundred to a few thousand. Before the commercial hunting era, there would have been hundreds of thousands in the oceans. The findings were presented at the International Whaling Commission's (IWC) annual meeting. Numbers of other large species such as fin whales and humpbacks are also rising in many parts of the world. "The most recent data is really encouraging," said the IWC's head of science Greg Donovan. "Blue whales have now been increasing by about 7-8% per year for the last 10 years at least, for which we have good data.