Luckily in the last fifty years whale hunting ban did the trick and blue whale population is showing signs of recovery, according to some scientists they are thriving in Antarctic by 6% a year, while in Atlantic around 3-4 % a year. Current number is still way below the number of the beginning of the 20th century but at least we can talk about steady progress, and by the current looks of it the largest animal on our planet will avoid extinction, well at least for time being.
About 200 animals have been recorded in the eastern Atlantic and 440 in the west which is something that hasn't been seen for years, and it could mean recovery in population of these giants. Of course if the hunting ban stays in place, and climate change doesn't mess entire ocean food chain.
Blue whales - The largest animals of our planet showing signs of population increase.