"Walleye Pollock"

Walleye pollock (Gadus chalcogrammus) are broadly distributed throughout the North Pacific with the largest concentrations found in the Eastern Bering Sea.

This is a three species stock assessment for walleye pollock (Gadus chalcogrammus), Pacific cod (Gadus macrocephalus) and arrowtooth flounder (Atheresthes stomias), from the Eastern Bering Sea (EBS), Alaska updated from Holsman et al.(2016).

Elizabeth Siddon is a recipient of the 2019 Presidential Early Career Award for Scientists and Engineers (PECASE).

This chapter covers the Eastern Bering Sea (EBS) region—the Aleutian Islands region (Chapter 1A) and the Bogoslof Island area (Chapter 1B) are presented separately.

The base model projection of female spawning biomass in 2019 is 345,352 t, which is 62.4% of unfished spawning biomass (based on average post-1977 recruitment) and above B40% (221,000 t), thereby placing GOA pollock in sub-tier “a” of Tier 3. New survey data in 2018 are highly contrasting, with the 2018 Shelikof Strait acoustic survey indicating high biomass, and the ADFG trawl survey indicating relatively low biomass (though increased from the previous two years). The risk matrix table recommended by the SSC was used to determine whether to recommend an ABC lower than the maximum permissible. The table is applied by evaluating the severity of three types of considerations that could be used to support a scientific recommendation to reduce the ABC from the maximum permissible. We identified substantially increased concerns for the stock assessment, the population dynamics of pollock, and environmental/ecosystem factors that are likely to affect pollock.

Ageing Methodology of Walleye Pollock.

See how scientists use saildrones—autonomous sailing vessels with customized acoustic technologies—to study whales, fish, and seals in remote parts of the ocean.

Walleye pollock (Gadus chalcogrammus; hereafter referred to as pollock) is a semi-pelagic schooling fish widely distributed in the North Pacific Ocean. Pollock in the central and western Gulf of Alaska (GOA) are managed as a single stock independently of pollock in the Bering Sea and Aleutian Islands. The separation of pollock in Alaskan waters into eastern Bering Sea and Gulf of Alaska stocks is supported by analysis of larval drift patterns from spawning locations (Bailey et al. 1997), genetic studies of allozyme frequencies (Grant and Utter 1980), mtDNA variability (Mulligan et al. 1992), and microsatellite allele variability (Bailey et al. 1997).

Multi-species statistical catch-at-age models (MSCAA) are an example of a class of multi-species ‘Models with Intermediate Complexity for Ecosystem assessments’, which have particular utility in addressing both strategic and tactical EBFM questions.

Alaska pollock (Gadus chalcogrammus) are broadly distributed throughout the North Pacific with largest concentrations found in the Eastern Bering Sea. The Bogoslof region is noted for having distinct spawning aggregations that appear to be independent from pollock spawning in nearby regions. The Bogoslof management district (INPFC area 518) was established in 1992 in response to fisheries and surveys conducted during the late 1980s, which consistently found a discrete aggregation of spawning pollock in this area during the winter. The degree to which this aggregation represents a unique, self-recruiting stock is unknown but the persistence of this aggregation suggests some spawning site fidelity that called for independent management. The Bogoslof region pollock has also been connected with the historical abundance of pollock found in the central Bering Sea (Donut Hole) due to concentrations of pollock that appeared to be moving toward this region prior to spawning (Smith 1981). For the purpose of management within the US zone, pollock from this region are managed separately.