"Sea otters are making a comeback off the British Columbia coast, after being wiped out by the fur trade in the early 1900s. But as they flourish, they're also changing the entire underwater ecosystem."
Here is what a friend of mine had to say about this video. It is an interesting and fair assessment of the situation.
"The story of the sea otter is a bit complicated. For more see :Sea otter conservation - Wikipedia They continue to struggle off the coast of California, have made somewhat of a comeback along Canada after controversial reintroduction (this video), and appear to be holding their own or declining in Alaska. Their main threats are considered to be fishing gear, oil spills, climate change, and disease."