Shore-Based Observers Strengthen Catch Accounting in Alaska’s Pollock Fishery

A shore-based fisheries observer collects data from a salmon caught in the pollock fishery at a fish processing plant in Alaska. Credit: NOAA Fisheries/North Pacific Observer Program

NOAA Fisheries is required by law to monitor fishery catches to ensure sustainable management of U.S. fisheries. The Alaska pollock fishery is the largest U.S. fishery by volume, and one of the largest in the world. Accurate accounting of pollock and other landed species-along with the catch of prohibited species such as salmon and halibut-is critical for science-based management and compliance with regulations. Traditionally, fisheries observers working on-board Alaska pollock vessels filled this role by collecting catch information and biological samples. These data contribute to stock assessments and catch accounting.

However, deploying at-sea observers can be both logistically challenging and expensive in some fisheries. As a result, hybrid monitoring programs, which combine electronic monitoring at sea with human shore-based observers, are becoming more common. They are well suited for low-discard fisheries which land all, or most of, the catch.

Researchers at the Alaska Fisheries Science Center evaluated the implementation of shore-based observersin the Alaska walleye pollock trawl fishery. The study, conducted under a voluntary exempted fishing permit, examined whether shore-based observers stationed at fish processing plants could:

• Meet core monitoring responsibilities
• Fulfill expanded sampling duties
• Verify the accuracy of industry-reported catch data

Monitoring a High-Volume Fishery

Scientists evaluated observer data collected between January 2020 and November 2023. They were collected during more than 4,000 pollock offloads at 14 shoreside fish processing plants in the Bering Sea and Gulf of Alaska. Under the exempted permit, electronic monitoring systems monitored fishing activity at sea for regulatory compliance, while shore-based observers focused on sampling landed catch.

Shore-based observers collected species composition data to support catch accounting and verify industry catch reporting. They gathered biological data to support stock assessments, including fish lengths and weights, sex, and otoliths, which are used to determine fish age. Observers prioritized accounting for prohibited species such as salmon and halibut.

A fisheries observer identifies the species of salmon that was caught in the pollock fishery in Alaska. Credit: NOAA Fisheries/North Pacific Observer Program

"Shore-based observers primarily focused on monitoring offloads to obtain accurate counts of salmon. This was particularly important for Chinook salmon, which has strict catch limits that can affect fishery closures," said Andy Kingham, fishery biologist with the Alaska Fisheries Science Center.

In the Bering Sea, all pollock offloads were selected for shoreside salmon monitoring and species composition sampling. In the Gulf of Alaska, approximately 30 percent of offloads were randomly selected. In both areas, observers used offloads to compare the species recorded by observers with those listed in the industry-reported offload receipts (also called fish tickets).

Measuring Performance and Sampling Needs

The study found that shore-based observers consistently met core monitoring responsibilities-specifically salmon accounting. They were able to take on expanded sampling duties in a fishery characterized by extremely large, frequent offloads and fast-paced fish processing. Observers not only generated data necessary for management, but also provided useful information for evaluating whether sampling levels were sufficient to detect rare species and bycatch.

Appropriate sampling levels and data collection necessary for management vary by fishery, region, and management context. To help evaluate these differences, scientists developed an approach integrating four key components:

• Assessed observer performance relative to program goals
• Evaluated sampling sensitivity, including the ability to detect rarely caught species
• Compared data between observer samples and industry-reported landings
• Prioritized sampling objectives, making trade-offs among competing monitoring needs

This approach can be used by any fishery around the world to evaluate the level of sampling needed for different management and monitoring objectives.

Validating Industry-reported Data

Comparisons between shore-based observer data and industry-reported fish tickets showed that industry-reported data were not always reliable for all species groups. Some species-including skates, forage fishes, and certain rockfish and flatfish-were under-reported, aggregated, or misidentified on fish tickets.

A fisheries observer monitors pollock being offloaded at a processing plant in Alaska. Credit: NOAA Fisheries/North Pacific Observer Program

"Our results show that shore-based observer programs do not simply duplicate industry reporting. Instead, they strengthen the accuracy of catch accounting by providing independent verification and identifying where reporting can be improved," stated Jason Jannot, supervisory fishery biologist at the Center.

By validating industry-reported data and identifying reporting gaps, shore-based observers play a critical role in improving and maintaining confidence in the data used for fisheries management.

Implications for Hybrid Monitoring Programs

The study demonstrates that shore-based observers can successfully support fisheries management in high-volume fisheries. They can also operate within hybrid monitoring programs that rely on electronic monitoring at sea for regulatory compliance. At the same time, the findings highlight the importance of balancing core monitoring requirements (salmon accounting) with expanded sampling objectives (biological samples for stock assessments).

"As more fisheries adopt hybrid monitoring approaches, the need to evaluate performance and make trade-offs transparent will only increase," said Christian Gredzens, fishery biologist at the Center.

By providing an approach for evaluating and optimizing shore-based monitoring programs, this research offers tools that can be applied beyond the Alaska pollock fishery. Under hybrid monitoring programs, electronic monitoring supports at-sea regulatory compliance. Shore-based observers play a critical role in validating industry-reported landings and generating independent scientific data used in fisheries management.

The authors thank their industry partners and the fisheries observers for their hard work and support of this research.