April 6, 2026 — A team of researchers from NOAA’s Alaska Fisheries Science Center, the University of Alaska-Fairbanks, and Alaska BioMap, Inc., recently published the most comprehensive population genetic assessment of Pacific cod. Pacific cod is a commercially and ecologically important species in the North Pacific Ocean, and this study identified four distinct genetic stocks. This research provides critical, novel information for setting appropriate stock boundaries for Pacific cod. It shows that our management boundaries generally align with the genetic structure across this region.
Genetic Stock Identification with a New Cost-Effective Tool
“We were interested in using advanced genetic techniques to determine genetic differences among Pacific cod from different regions in Alaska,” said Sara Schaal, lead author of the study. “We collected samples from fish caught in known spawning grounds during the NOAA winter trawl surveys and from our fisheries partners within the Freezer Longline Coalition.”
Schaal and her colleagues first conducted whole-genome sequencing, which identified four genetically distinct stocks of Pacific cod within the Gulf of Alaska and Bering Sea:
- Eastern Gulf of Alaska
- Western Gulf of Alaska/eastern Bering Sea
- Aleutian Islands
- Northern Bering Sea
Results highlight significant genetic mixing between Pacific cod spawning in the western Gulf of Alaska and the eastern Bering Sea. This aligns with satellite tag studies that showed high proportions of Pacific cod movement between these two regions outside of spawning season.
The stocks identified using genetics match current management areas, except for the eastern Bering Sea and western Gulf of Alaska, which are currently managed as separate stocks. However, these data show they cannot be distinguished at the genetic level. Additionally, results clearly delineate two distinct stocks within the Gulf of Alaska—with a break between the western and eastern Gulf of Alaska. This had been suggested by previous work, but was clearly shown in this new study.