NOAA Fisheries is responsible for science-based management of Alaska’s commercial fisheries in federal waters through the Magnuson-Stevens Fishery Conservation and Management Act. The fisheries are managed with the goal of having sustainable fish stocks that can support both fisheries and the broader marine ecosystem into the future. NOAA Fisheries’ Alaska Fisheries Science Center provides the science to support the management of groundfish (including pollock) in the Gulf of Alaska, Bering Sea, and Aleutian Islands through year-round collection, analysis, interpretation, and communication of data through the North Pacific Fisheries Management Council. Data for commercial crab species in federal waters of the Bering Sea are also provided for the Council and State of Alaska - Board of Fisheries management decisions. The Alaska Fisheries Science Center provides data to support the State’s management of salmon stocks in Alaska and support federal management of Cook Inlet salmon Fisheries as well.

Generally, fish stock assessment models estimate the numbers of fish at different ages, the rate at which they grow and reproduce, and the rate at which they die. These biological dynamics of a fish stock are influenced by environmental conditions, the availability of food, and predation. In the North Pacific Fisheries Management Council process, these ecosystem factors that affect how many fish are available for fisheries are summarized in the form of Ecosystem Status Reports, Ecosystem and Socioeconomic Profiles, and Risk Tables.

Let’s follow the annual cycle of environmental data collection and synthesis for the Gulf of Alaska pollock stock, from winter surveys through to the following fall’s North Pacific Fisheries Management Council meeting. Pollock support an important commercial fishery and numerous communities in the Gulf of Alaska but also provide food for other fish, birds, and marine mammals in the marine ecosystem.

Winter

Every winter, in the Gulf of Alaska, adult walleye pollock migrate from deeper slope waters of the Gulf of Alaska onto the shelf to aggregate and spawn. Scientists from the Alaska Fisheries Science Center go out on the NOAA Research Vessel Oscar Dyson in February and March to count the largest concentrations of spawning pollock in Shelikof Strait and southwest along the Alaskan Peninsula. This survey provides estimates of the number, biomass, size, maturity, and ages of adult pollock present in the stock, which are important data for the pollock stock assessment. 

NOAA and our partners also collect satellite- and mooring-based information on ocean conditions, such as temperatures, the position and strength of eddies, and local wind direction, to monitor for change and track large-scale climate events (like El Niño and extreme heat waves) in the winter. Some up-to-date satellite-based information can be easily viewed through newly developed applications, such as for sea surface temperatures and the potential presence of marine heatwaves. These data provide information on the environmental conditions that are affecting adult spawning pollock and the habitat quality of newly arrived young pollock.

Spring

Spring is an important time for vulnerable, young pollock to grow and eat. It is also a time when other fish, marine mammals, and seabirds love to eat them! NOAA Fisheries scientists venture out again on the NOAA Research Vessel Oscar Dyson to Shelikof Strait and the Alaskan peninsula to estimate the number of pollock hatched that year. The survey also collects data to estimate the amount and species of zooplankton (food for pollock) in the region. These data offer a first look at the potential size of the latest cohort of pollock entering the stock, which can be tracked by surveys through their lifetime. The survey also provides valuable environmental information including the amount and quality of food available for the young pollock and many other fish, seabirds, and marine mammals to eat. Putting this information together, we can build our understanding of the current ecosystem status, as well as look 3 years into the future when these pollock are old enough to be fished. Managers and members of industry can plan for large or small fluctuations in the size of the pollock stock and the resulting fishery. 

In the spring, NOAA’s Alaska Fisheries Science Center hosts a workshop to discuss early indications of how the marine ecosystem is developing that year. It is a time to identify potentially beneficial or challenging environmental conditions that might be developing for key commercially fished species, such as pollock. NOAA researchers— along with collaborators from Alaska Federally-recognized Tribes, Alaska Native organizations, state and other federal agencies, academia, and non-government agencies, seafood industry, and citizen science— share information and insights on what they are observing that year. Topics range from oceanography to phytoplankton, zooplankton, forage fish, groundfish, seabirds, marine mammals, and human fishing communities. We use indicators, such as seabird population growth (as seabirds feed on similar prey as commercial fish such as pollock), or productivity at the base of the food web, to determine how the marine ecosystem is changing over yearly to longer time periods. The results serve as a proxy for understanding how healthy pollock and other fished stocks will be in the coming year and in years to come. The data are often very new, and it is not uncommon for scientists to send data straight from a research vessel or to call in from a seabird monitoring colony in the middle of the Gulf of Alaska! 

Summer

Summer in the Gulf of Alaska brings longer days and warmer water temperatures, and when the conditions are right, this kicks the productivity of the ecosystem into high gear. Adult pollock spread out across the shelf of the Gulf of Alaska seeking prey resources while also looking to avoid becoming prey themselves. The more growth and energy reserves (e.g. fat) they can put on during the summer helps prepare them for the coming lean times in the winter and spawning of the next generation. Young pollock are maximizing growth and energy stores before winter approaches, and many other fish, seabirds, and marine mammals are doing the same. This makes the summer an incredibly important period of time for stock assessment and ecosystem surveys, so multiple NOAA surveys monitor stocks of adult groundfish (including pollock), Steller sea lions, juvenile and returning salmon, capelin, and zooplankton during the summer. For instance, the summer bottom trawl surveys provide invaluable information on the stock size, distribution, age, and overall health (condition) of the pollock stock in the Gulf of Alaska. These data are vital to the stock assessment process and the determination of fishing quotas throughout the region. Our collaborators from other federal agencies, Alaska Federally-recognized Tribes, academia, non-governmental organizations, and citizen science groups are collecting data on seabirds, whales, forage fish, crab, intertidal communities, and oceanography. Scientists work very quickly to double check the data they have collected, process all the samples, and have most of this information ready to share by early fall so we can use ‘same-year’ data to inform pollock fisheries management. This is a key strength of our ecosystem data pipeline in Alaska, and reflects the dedication of the science community to support ecosystem-based management of our fisheries.  

Fall

The final season in this cycle is a time for synthesis and communication. The pollock stock assessment model adds data from multiple surveys and from the fishery from the past year to estimate the number of pollock in the stock, and the total reproductive potential of the stock. This estimate is used to determine how many fish can be sustainably caught in the coming year (Acceptable Biological Catch). The goal is to estimate how many pollock can be caught by the fishery, while leaving enough fish in the water to support a healthy and productive pollock stock and greater marine ecosystem in the years to come. 

Pollock-related ecosystem information is gathered into the broader Ecosystem Status Report for the Gulf of Alaska, and species-specific Ecosystem and Socioeconomic Profiles. Pollock risk tables synthesize the ecosystem information not included in the pollock stock assessment model, and can be used to document concerns and/or justify a reduction to the maximum permissible Acceptable Biological Catch. For example, information is often included on what is happening with pollock prey including zooplankton and forage fish, competition for that food, and the amount of arrowtooth flounder and other predators trying to eat pollock. The Gulf of Alaska pollock assessment also includes new research such as a recent study linking pollock spawn timing to ocean temperature. As the Gulf of Alaska waters continue to warm over time, pollock spawn timing is earlier in warmer years. Survey-estimates of pollock (and thus the final stock assessment) can be more accurate by accounting for the variable peak timing of their spawning aggregation. Decades of research and monitoring provide context for the potential of the pollock stock to have a more or less productive year. Broader Gulf of Alaska ecosystem characteristics are also summarized and discussed to provide an ecosystem base to the species-specific discussions around fisheries catch.

The North Pacific Fishery Management Council conducts numerous meetings throughout the fall and winter in which this information is presented to expert panels, reviewed, and discussed. The final step for pollock is a meeting in December in which the harvest quotas for pollock and the other Alaskan groundfish are determined for the upcoming year. The Council’s final annual pollock harvest decision (Total Allowable Catch), incorporates science from the basic research, to the data collection, the assessment, and the various ecosystem reports and products listed above. 

We are also starting to incorporate climate data and information to complement our ecosystem-based fishery management data collection efforts and to predict and monitor impacts of warming ocean waters. These impacts include marine heatwaves, decreases in ocean pH, sea level rise, changes in ocean circulation and stratification, and potential changes in species distributions, ecosystem productivity, and food-web structure. We are also testing new technologies (e.g., aerial and seagoing drones, satellites, specialized underwater camera systems and infrared camera systems, near-infrared spectroscopy) and exploring advancements in the field of genetics (e.g., the use theeDNA), and strengthening our socio-economic program to augment our ecosystem, fish, crab and marine mammal survey data. These efforts can provide more real-time information (quicker processing of data) and enable us to capture areas and times of the year when we are unable to collect survey data to aid in our understanding of changing ocean conditions and the impacts on fishing and coastal communities.

The inclusion of ecosystem and climate science in fisheries management allows for an adaptive and flexible management system that can more rapidly react to changes in the environment. The vast, collaborative effort of information collection and synthesis is also informative to the fishing industry and Alaskan communities who depend upon the marine environment on a daily basis. Understanding broader changes in the marine ecosystem, as well as the dynamics of specific fish stocks like pollock, helps us all be more resilient and prepared for the years ahead.