Tuesday June 16, 2026
NOAA —
Pacific cod support Alaska’s second largest groundfish fishery and play a critical role in the Bering Sea ecosystem. In recent decades—particularly from 2017 to 2019—the Bering Sea experienced unusually warm temperatures and minimal sea ice. These conditions appear to have shifted Pacific cod distributions farther north compared to colder years, raising questions about long-term changes in population distribution and demographic structure.
Understanding a Shifting Species
In response to industry concerns and scientific data needs to support management, a research team launched a satellite tagging study in 2019. Led by Dr. Susanne McDermott—the Gulf of Alaska bottom trawl survey lead—the team included fisheries biologists Julie Nielsen, Kimberly Rand, and many others. McDermott recalled, “There was tremendous anxiety over what’s going on. Why are these fish in different places? Is this something that’s changing on a population level? Is this just the same population moving into different areas?”
The summertime distribution of Bering Sea Pacific cod is usually centered in the southeastern portion of the region. Cod distribution typically varies with the extent of sea ice in the Bering Sea during the previous winter. It shifts northward in warm years and southward in cold years.