Sea ice has shrunk, but scientists are seeing signs that Alaska's bowhead whales are flourishing.

"Until now, bowhead whales in the U.S. Pacific Arctic were thought to experience minimal predation pressure from killer whales. Our study suggests that is no longer the case,” said Amy Willoughby.

Two key factors that govern the Arctic ecosystem are rapidly changing: ice and light. The Arctic is the fastest-warming place on earth, and ice that used to form on the surface of the ocean is vanishing.

The open ocean off Utqiagvik in fall and early winter is evidence of climate change. Remarkably, bowhead whales appear to be thriving, although there are new challenges. Kidney-worm infections have been detected in bowheads, possibly brought by other species of whales coming north. And then there are the killer whales, a natural predators of bowheads now venturing north.