Near Real-time Temperatures from the 2026 Bering Sea Bottom Trawl Survey

Survey Progress and Bottom Temperatures

Every year, NOAA’s Alaska Fisheries Science Center conducts the eastern Bering Sea bottom trawl survey. We are mandated by the Magnuson-Stevens Act to collect distribution and abundance data for fish, crab, and other bottom-dwelling species in the Bering Sea. These data inform stock assessments and ecosystem status reports for the North Pacific Fisheries Management Council.

Temperature is one of many factors that influences species’ ranges and population sizes. For instance, we see many species moving farther north as ocean temperatures warm. To understand what’s going on in the Bering Sea, we record ocean bottom and surface temperatures at each sample station on the survey. These data will help us understand how variations in temperature over time relate to the fish and crab we find—or don’t find—at the same station.

We are updating this page with the most recent bottom temperatures recorded on most weekdays during the survey. Check back frequently to see the updated temperature maps in near real-time. Note that in 2025 the survey included both the eastern and northern Bering Sea survey areas. In 2026, we are only surveying the eastern Bering Sea area.

We have conducted the eastern Bering Sea survey annually since 1982 (except in 2020) making this the longest running, standardized time series of fish and invertebrate data in the region—43 years! Learn more about this survey, view temperature maps from previous years, and see examples of how these data are collected and used in this story from 2023.

All data collected on these surveys are and will be publicly accessible from: 

• Fisheries One Stop Shop public data portal
• Distribution Mapping and Analysis Portal
• Alaska Fisheries Information Network

View daily maps of our progress and bottom temperatures throughout the survey. The last page includes a map of the full Bering Sea survey footprint with bathymetry at 50, 100, and 200 meters.

Documenting the Bering Sea Cold Pool

Survey data are crucial for understanding the extent of the cold pool, which is an important oceanographic feature of the Bering Sea.

Each spring, the previous winter’s sea ice melts to create dense, cold, ocean water, which sinks to the bottom of the Bering Sea. This creates the cold pool, which is defined as the total area where bottom temperatures are less than or equal to 2°C. The location of this cold pool changes from year to year and affects the movement and ranges of fish, crab, and other bottom-dwelling species. And it can act as a boundary separating Arctic species from subarctic species.

Commercially important fish like walleye pollock, Pacific cod, and snow crab are dependent on the location of the cold pool. Due to warming ocean temperatures in the Bering Sea, we track and closely monitor the location of the cold pool by collecting ocean bottom temperatures at each station.

Learn more about temperature anomalies, the cold pool, and how bottom temperatures in the Bering Sea have changed over time.

Survey Dates

The 2026 eastern Bering Sea bottom trawl survey runs from the beginning of June to the end of July on the F/V Northwest Explorer and the F/V Alaska Knight. After the survey ends, we will stay at sea for gear modernization trials until August 13. Learn more about our efforts to modernize our surveys.

Throughout the survey, the vessels are scheduled to be in port on the following dates:

• Depart Dutch Harbor May 31 to start the survey
• Dutch Harbor on June 17 between legs 1 and 2
• Dutch Harbor on July 7 between legs 2 and 3
• Dutch Harbor on July 28 between legs 3 and 4, completing the 2026 eastern Bering Sea bottom trawl survey, and beginning gear modernization trials
• Dutch Harbor on August 13 at the end of the final fourth leg

On August 13, both vessels will return to port for demobilization. Our survey scientists will return to Seattle and Alaska to finalize the data collected. 

We will keep the communities informed of our survey progress by posting regular updates via the website and social media (Facebook and Instagram). At the end of the survey, we will present the preliminary results in our fall University of Alaska Fairbanks Strait Science Seminar and the September Joint Groundfish Plan Team presentation.

Survey Location

The eastern Bering Sea bottom trawl survey began in Dutch Harbor, Alaska, and the vessels transited to eastern Bristol Bay to begin sampling. From Bristol Bay, we proceed westward completing north-south columns of the survey on our way to the shelf edge. The east-to-west survey progression is based on an understanding of historical trends in fish movement. This ensures the survey moves in the opposite direction of the seasonal on-shelf (eastward) migration patterns typical of yellowfin sole and other species. 

Pictures from the Field

What does survey life and research look like? Check out the 2026 photo gallery to see updates from throughout the survey. These photos show the incredible places that NOAA scientists go and showcase our mission in ways that words cannot.

Additionally this year, we are partnering with the Alaska Ocean Observing System (AOOS) to look for harmful algal blooms in Alaska. The FV Northwest Explorer is carrying a Imaging Flow Cytobot. This is an automated microscope that takes water samples and produces real time images of individual phytoplankton. The images are used to detect harmful species such as Alexandrium, Pseudo-nitzschia, and Dinophysis. Data collected by the cytobot are used for research projects and to alert communities around the state of potential blooms.