King and snow crab populations in the Bering Sea have plummeted ahead of the harvest season, some by 99% compared to previous years.

NOAA Fisheries' summer trawl survey shows Norton Sound red king crab are moving, Arctic cod numbers have dropped significantly, and Pacific cod are continuing to increase as the Northern Bering Sea ecosystem undergoes drastic change.

During a workshop in Nome this week, scientists and residents discussed algal toxins’ role in the changing Bering Sea ecosystem.

Frigid north winds blow down from the Arctic Ocean, freeze saltwater and push sea ice south. The ice normally prevents waves from forming and locks onto beaches, walling off villages. But not this year.

The “thermal curtain” is another expression for “cold pool” that acts as a barrier to keep some species—pollock and Pacific cod, for example — from migrating across the eastern Bering Sea shelf and northward toward the Bering Strait. For the first time in 37 years of surveying the Bering Sea, we could not find the cold water barrier.

Researchers now are uncertain when and to what extent the ice may return, and have scrambled to better understand the consequences of back-to-back years of its loss.