In the darkness of the ocean, the biggest animal in the world sings.

Blue whales breathe air, but they spend most of their time underwater where it’s too dark to see. Instead of sight, they use songs, clicks and whistles. The echoes of these sounds help them find their way around the ocean and locate their feeding grounds. They also use them to talk to each other. Impressively, these marine mammals can use sound to communicate with each other from up to 1,600 kilometres away.

Blue whales live in oceans around the world. For a long time, humans over-hunted them. Their meat, oil and other parts were valuable goods. When Canada banned most whaling in 1972, their population in our waters was dangerously low. We are still learning what that will mean for their recovery.

Today many laws protect whales, including Canada’s Species at Risk Act. While blue whale numbers are still low here, there is hope. Other whale species have begun to recover in Canadian waters, and blue whale numbers are increasing elsewhere.

Of course, protection from whaling is just the first step. Whales still face other challenges, including a big increase in human-made underwater noise. The sounds from our ships interrupt whale songs, making it harder for them to find food and raise their young. The next phase of whale conservation is clear: we must stop making such a racket!