Alaska Pollock
Alaska Pollock
Gadus chalcogrammus
Also Known As
Pollock, Walleye pollock, Pacific pollock
Quick Facts
Region
Alaska
Alaska pollock
Alaska pollock
About The Species
Alaska pollock—also known as walleye pollock—is a key species in the Alaska groundfish complex and a target species for one of the world's largest fisheries. Pollock is a semipelagic schooling fish widely distributed in the North Pacific Ocean with largest concentrations in the eastern Bering Sea.
U.S. wild-caught Alaska pollock is a smart seafood choice because it is sustainably managed and responsibly harvested under U.S. regulations.
Population Level
Above target population levels for the Aleutian Islands, Eastern Bering Sea, and Western/Central/West Yakutat Gulf of Alaska stocks. The population levels are unknown for Bogoslof and Southeast Gulf of Alaska.
Fishing Status
At recommended levels.
Habitat Impacts
The Alaska pollock fishery uses midwater trawl nets that, although sometimes making contact with the bottom, have minimal impact on habitat.
Bycatch
The Alaska pollock fishery is one of the cleanest in terms of incidental catch of other species (less than 1 percent).
Status
- The 2018 stock assessments for the Aleutian Islands, Eastern Bering Sea, and Western/Central/West Yakutat Gulf of Alaska indicate that pollock stocks are not overfished and spawning biomass is estimated to be above the target level for all three stocks.
- To assess the health of the pollock population, scientists estimate the female spawning biomass—a measure of the pollock stock’s ability to reproduce.
- Regulations for the pollock fishery aim to conserve the spawning population to ensure pollock can successfully reproduce and keep the population size at healthy levels.
- The overfished status for the Bogoslof and Southeast Gulf of Alaska stocks is unknown. These areas are also closed to fishing for pollock with trawl gear.
- No stocks are currently subject to overfishing.
Appearance
- Pollock is a member of the cod family.
- They can grow as long as 3 feet but typically reach lengths between 12 and 20 inches and weigh between 1 and 3 pounds.
- They have speckled coloring that helps them blend in with the seafloor to avoid predators.
Biology
- Alaska pollock grow fast and have a relatively short life span of about 12 years.
- As a result, they are generally more productive compared to slower growing, longer living species.
- Some pollock begin to reproduce by the age of 3 or 4 and are extremely fertile, so each generation replaces aging or harvested fish in just a few years.
- In the spring, pollock migrate inshore to shallow water to breed and feed.
- They move back to warmer, deeper waters in the winter months.
- The survival of young pollock depends on several factors, such as the availability of food, environmental conditions, and predation.
- Their survival rate is highly variable, which can potentially cause large fluctuations in the abundance of pollock in a matter of a few years.
- Juvenile pollock eat zooplankton (tiny floating animals) and small fish.
- Older pollock feed on other fish, including juvenile pollock.
- Many other species—including Steller sea lions and other marine mammals, fish, and seabirds—feed on pollock and rely on them for survival.
Where They Live
- Alaska pollock are found throughout the North Pacific Ocean but are most common in the Bering Sea.
Management
- NOAA Fisheries and the North Pacific Fishery Management Council manage the Alaska pollock fishery.
- Managed under the Groundfish Fishery Management Plans for the Gulf of Alaska and the Bering Sea/Aleutian Islands:
- The Alaska pollock fishery is a great example of how science-based management and monitoring can help ensure the long-term sustainability of the resource.
- The Bering Sea fishery is one of the first U.S. fisheries to be managed with catch shares and is often considered one of the best-managed fisheries in the world.
Featured News
The F/V Commodore fishing for pollock in the Eastern Bering Sea. Credit: Brent Paine/United Catcher Boats.
The Bering Sea cold pool, a bottom water mass that is < 0-2o C resulting when winter sea ice recedes affects fish movement. Warmer water temperatures and reduced sea ice in recent years resulted in shrinkage of the cold pool. Figure: NOAA Fisheries.
Credit: NOAA Fisheries.
Larval pollock. Photo: NOAA Fisheries.
Related Species
Science Overview
Alaska Walleye Pollock Research in Alaska
Surveying Pollock Populations
We gather information about the number, location, and age of pollock in Alaskan waters during annual surveys using acoustic technology, midwater trawls, and bottom trawls. These data are combined with information collected by fishery observers.
Pollock in the Gulf of Alaska, eastern Bering Sea, and Aleutian Islands are managed as separate stocks based on the results of genetic studies, biological characteristics, and analyses of larval drift patterns from spawning locations.
Early Life Studies
We study factors affecting young pollock survival to recruitment (when they reach a size available to the fishery at around 3 years old). These survival rates can vary dramatically from one year to the next and this affects pollock populations, posing challenges for the fishery and fishery managers. Scientists have linked these ups and downs to variability in environmental conditions during the early life of pollock.
Understanding how young pollock respond to environmental changes helps scientists understand and communicate future uncertainty in population size and hence size of eventual fishing quotas to managers, the public, and fishery stakeholders.
Age and Growth
We determine the age of individual fish to provide data for age-structured modeling of populations and continue to develop new techniques to age walleye pollock.
An Ecosystem Approach
Environmental factors affect walleye pollock populations in the Eastern Bering Sea, Aleutian Islands, and Gulf of Alaska. Prey availability and the number of fish, seabird, and marine mammal predators and their spatial overlap with pollock also have a large impact. Comprehensive scientific observer coverage aboard commercial fishing vessels closely monitors catch and bycatch to help gauge possible impacts of humans and the fishery on the ecosystem. Our scientists work closely with industry and managers to mitigate potential adverse impacts through a variety of conservation and management measures, and by developing appropriate gear modifications.
Each year, a comprehensive ecosystem status report on climate and fishing is compiled in Ecosystem Assessments and Report Cards. These reports are an important step towards achieving the ecosystem-based management goals of the North Pacific Fishery Management Council: to maintain predator-prey relationships, diversity, and habitat, and to monitor effects of climate change.
Walleye pollock. Photo: NOAA Fisheries.
Assessing Past, Present, and Future Pollock Stocks
We create Stock Assessment and Fishery Evaluation (SAFE) reports to summarize the best available scientific information concerning the past, present, and possible future condition of stocks, marine ecosystems, and fisheries that are managed under Federal regulation, including the walleye pollock fishery. These reports provide information to the North Pacific Fishery Management Council for determining annual harvest levels from each stock; documenting significant trends or changes in the resource, marine ecosystems, and fishery over time; and assessing the relative success of existing state and Federal fishery management programs.
Additional Resources
- Age and Growth Procedures for Otolith Examination
- Age Reading Interactive Demonstration
- Fish Species Maximum Age Data
- Groundfish Catch Percentage and Value
- Resource Ecology and Ecosystem Modeling, Number of Stomachs Database
- Alaska Ichthyoplankton Information System Database
