Update of Navarin walleye pollock stock assessment

Estimation of Age-Specific Migration in an Age-Structured Model

The standard Eastern Bering Sea (EBS) walleye pollock (Theragra chalcogramma) age-structured stock assessment model has no spatial dimension. To better understand its dynamics on finer spatial and temporal scales, an age-specific movement (ASM) model was developed. The ASM model stratifies the assessment data into two regions (northwest [NW] and southeast [SE] EBS), includes movement, and allow...

Interannual and Spatial Variability in Maturity of Walleye Pollock Gadus chalcogrammus and Implications for Spawning Stock Biomass Estimates in the Gulf of Alaska

Catch quotas for walleye pollock Gadus chalcogrammus, the dominant species in the groundfish fishery off Alaska, are set by applying harvest control rules to annual estimates of spawning stock biomass (SSB) from age-structured stock assessments. Adult walleye pollock abundance and maturity status have been monitored in early spring in Shelikof Strait in the Gulf of Alaska for almost three decad...

Spatial and Temporal Variability in Size at Maturity of Walleye Pollock in the Eastern Bering Sea

—Size at maturity is incorporated into stock assessments of walleye pollock Theragra chalcogramma. For eastern Bering Sea walleye pollock, however, this important biological variable has not been examined since 1976 and possible interannual and geographic variations have never been evaluated. Maturity condition and fish length data were collected from 10,197 walleye pollock aboard factory trawl...

The Origins of Chum Salmon Bycatch in the 1994 Bering Sea Trawl Fishery for Walleye Pollock Determined by Genetic Stock Identification

Climate change causing phase transitions of walleye pollock (Theragra chalcogramma) recruitment dynamics.

In 1976 the North Pacific climate shifted, resulting in an average increase of the water temperature. In the Gulf of Alaska the climate shift was followed (i.e. early 1980s) by a gradual but dramatic increase in the abundance of groundfish species that typically prey on pre-recruitment stages of walleye pollock. In the present study we used a previously parameterized model to investigate the ef...