NOAA Satellite Tagging Tracks Alaska Red King Crab Migration, Study Suggests Fixed Closed-Area Boundaries May Struggle to Adapt to Warming Seas

A satellite tagging study led by the U.S. National Oceanic and Atmospheric Administration's National Marine Fisheries Service (NOAA Fisheries) shows that the migration of red king crab (Paralithodes camtschaticus) along the Alaska coast is influenced by environmental factors. Conducted from late spring 2021 to autumn 2024, the study examined why red king crab in Bristol Bay, Alaska, migrate during specific periods of the year, and the results have been published in the Canadian Journal of Fisheries and Aquatic Sciences.

The research drew on data from annual bottom trawl surveys in the eastern Bering Sea, with participating institutions including NOAA's Alaska Fisheries Science Center, the Alaska Department of Fish and Game (ADF&G), the College of Fisheries and Ocean Sciences at the University of Alaska Fairbanks, and the Bering Sea Fisheries Research Foundation. Researchers used satellite tags to supplement traditional surveys in order to gain a more complete picture of when and where the crab stock moves. NOAA explained that this tagging technology does not transmit data in real time; instead, the tags surface on specific dates—October 11 to 15—and once at the surface transmit data to satellites for researchers to analyze the starting and ending points of movement.

Sean Hardison, a research assistant at the University of Alaska Fairbanks, first author of the study and formerly with NOAA, said that after the red king crab fishing season ended, model predictions were compared with actual catch data and the two generally matched. He said satellite tagging work in Bristol Bay has been ongoing, but the tag data had not previously undergone a formal evaluation like this one; the study combined movement models built from satellite tag data with bottom trawl survey data to predict where the crab stock would be when the commercial fishery opened in mid-October.

On this basis, the researchers built a spatial movement model to determine red king crab habitat preferences with respect to temperature, environment and depth. The results showed that red king crab move southwest and farther offshore from June to October, and move farther west in years when bottom water is warmer. During the three-year tagging study, the movement model was able to predict that red king crab would move in autumn to western or southwestern Alaska in search of deeper, colder waters such as those in Bristol Bay. NOAA said these predictions were validated by autumn commercial catch records from the Bristol Bay red king crab fishery; researchers are now applying the same model to other seasons.

In its research summary, NOAA Fisheries noted that the boundaries of regulated areas such as the Red King Crab Savings Area are fixed and cannot be adjusted to environmental conditions such as changing seasonal migration patterns. Erin Fedewa, a NOAA Fisheries fisheries biologist and co-author of the paper, said the study shows that the autumn distribution of red king crab in Bristol Bay changes with bottom water temperature, suggesting that dynamic rather than static spatial fishing closures may be more effective for red king crab; its modeling framework provides a tool for such spatial management measures.

Hardison said the findings do not prescribe new closed-area boundaries, but rather show how to integrate crab movement, survey and environmental data to identify key red king crab habitat and assess the potential effects of proposed closed-area adjustments; this can help find more effective ways to reduce bycatch, protect essential fish habitat, and support the Bristol Bay red king crab stock after more than a decade of low recruitment. NOAA said that since the paper was published, researchers have been expanding the work to male and female red king crab, studying migration patterns during winter and spring.

On fisheries management, the Alaska Department of Fish and Game announced statewide crab total allowable catch (TAC) limits in October, including a Bristol Bay red king crab TAC of 3.41 million pounds, an individual fishing quota (IFQ) of 3.07 million pounds, and a community development quota (CDQ) of 341,000 pounds. These figures were set after both biomass and effective spawning biomass were above the thresholds required to open the fishery. The fishery reopened in October 2023 after two years of closure; with supply scarce, the December 2023 crabbing season was commercially competitive. The fishery collapsed entirely after a "mystery mortality event" in 2022, then reopened for the 2023-2024 season and continued in the 2024-2025 season with doubled catch limits.