Video: Orcas appear in Vancouver's harbour

The revival of marine mammals off the B.C. coast has been one of the most positive environmental stories in years.

There have been spottings of Pacific white-sided dolphins, sea otters, and humpback whales in places where they had never been seen for decades.

While the "sixth extinction" is taking place in the Anthropocene Epoch and warrants much attention, there is good news taking place in some temperate regions.

In 2010, the Raincoast Conservation Society released a report chronicling more than 120 species of marine birds along the coast, including giant albatrosses.

And earlier this month, Sauder School of Business professor James Tansey filmed orcas in Vancouver's harbour. You can see them in the video below.