This video is called Humpback Whale Song.
From Wildlife Extra:
How many Humpback whales were there before whaling?
How many Humpbacks are "enough" for the North Atlantic?
February 2013. Building on previous genetic analyses to estimate the pre-whaling population of North Atlantic Humpback whales, a research team has found that Humpbacks used to exist in numbers of more than 100,000 individuals.