For eons, a one-of-a-kind population of killer whales has hunted chinook salmon along the Pacific Coast of the United States. For the last 40 years, renowned whale scientist Ken Balcomb has closely observed them. He’s familiar with a deadly pattern, as salmon numbers plummet orcas starve.

The orcas need roughly a million salmon a year, where to find a million fish? The solution, says Balcomb, is getting rid of four fish-killing dams 500 miles away on the largest tributary to what once was the largest chinook producing river on earth.

Studying whales is science. Removing dams is politics. Defiantly mixing the two, says Balcomb, has become the most important work of his storied career. Meanwhile, the race to extinction for salmon and orcas speeds up, nipping at the heels of the plodding, clumsy pace of political change in the Pacific Northwest, where dams and hydropower are king.