Eastern Bering Sea shelf walleye pollock (Gadus chalcogrammus) midwater abundance and distribution were assessed from Bristol Bay to the U.S.-Russia Convention Line between 12 June and 17 August 2016 using acoustic-trawl survey methods aboard the NOAA ship Oscar Dyson.

Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and Conservation Engineering (RACE) Division routinely conduct acoustic-trawl (AT) stock assessment surveys to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus).The survey (cruise DY2011-03) was conducted between 14 June and 12 August on the Gulf of Alaska shelf from 50-500 m depth extending from the Islands of Four Mountains to the Chiniak Trough east of Kodiak Island. The area referred to as the shelf includes transects that are roughly perpendicular to the continental shelf depth contours and extend in a general north-south direction from inshore bottom depths of <=50 m to upper continental slope bottom depths of >500 m. Smaller surveys were conducted in several bays and around islands including: Morzhovoi Bay, Sanak Trough, Pavlof Bay, the Shumagin Islands areas of Renshaw Point, Unga Strait, and West Nagai Strait, Mitrofania Island, Nakchamik Island, Shelikof Strait, Chiniak Trough, Barnabas Trough, and Alitak Bay. All activities were conducted aboard the NOAA ship Oscar Dyson, a 64-m stern trawler equipped for fisheries and oceanographic research. The survey followed established AT methods as specified in NOAA protocols for fisheries acoustics surveys and related sampling.

Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) Resource Assessment and Conservation Engineering (RACE) Division conducted an acoustic-trawl (AT) stock assessment survey of portions of the Gulf of Alaska (GOA) shelf to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus) during summer of 2013. The survey (cruise DY2013-07) was conducted between 8 June and 9 August on the Gulf of Alaska shelf from 50-1,000 m depth extending from the Islands of Four Mountains to Yakutat Bay. The area referred to as the shelf includes transects that are roughly perpendicular to the continental shelf depth contours and extend in a general north-south direction from inshore bottom depths of =50 m to upper continental slope bottom depths of > 1,000 m. Smaller surveys were conducted in several bays and around islands including: Sanak Trough, Morzhovoi Bay, Pavlof Bay, the Shumagin Islands area (including Renshaw Point, Unga Strait, and West Nagai Strait), Mitrofania Island, Nakchamik Island, Shelikof Strait, Alitak Bay,Barnabas Trough, Chiniak Trough, Marmot Bay, Prince William Sound, Kayak Island Trough, and Yakutat Trough. All activities were conducted aboard the NOAA ship Oscar Dyson, a 64-m stern trawler equipped for fisheries and oceanographic research. The survey followed established AT survey methods as specified in NOAA protocols for fisheries acoustics surveys and related sampling.

Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and Conservation Engineering (RACE) Division conducted an acoustic-trawl (AT) stock assessment survey of the western Gulf of Alaska (GOA) shelf to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus) in summer 2015. Previous surveys of the GOA were also conducted during the summers of 2003, 2005, 2011, and 2013 by MACE. The 2015 survey covered the shelf from the Islands of Four Mountains to Yakutat Trough including many associated bays and troughs. The biomass estimate for the entire survey area was 1,482,668 t. The majority of the pollock observed were located on the continental shelf (64%), Shelikof Strait (19%), east of Kodiak Island in Chiniak (2%) and Barnabas Troughs (6%), and in Marmot Bay (3%). The vast majority (91%) of the biomass for the entire survey was from fish 30-50 cm in length (likely mostly age-3 fish), Fish weight at length was slightly lower in fish greater than 40 cm FL compared to surveys conducted in the summer GOA in previous years. Backscatter was attributed to other species where possible. A biomass estimate was also calculated for Pacific ocean perch (Sebastes alutus, 407,988 t) and the relative abundance and distribution for euphausiids (primarily consisting of Thysanoessa inermis, but also including T. spinifera, T. raschii, and Euphausia pacifica) was estimated.

Shumagin Islands, Sanak, Morzhovoi, Pavlof

Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center's (AFSC) Resource Assessment and Conservation Engineering (RACE) Division conducted an acoustic-trawl (AT) survey of the Gulf of Alaska (GOA) shelf to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus) in summer 2017. Previous surveys of the GOA have also been conducted by the MACE program during the summers of 2003, 2005, 2011, 2013, and 2015. The 2017 survey covered the shelf from the Islands of Four Mountains to Yakutat Trough including many bays and troughs. Surface water temperatures across the GOA shelf averaged 11.6° C, overall, approximately 0.6° C cooler than in 2015 (mean 12.2° C) and 1.0° C warmer than in 2013 (mean 10.6° C), which were the only other surveys with comparable coverage. Large aggregations of age-0 pollock were observed throughout the survey but especially in the Shumagin Islands and Shelikof Strait areas. The estimated amounts of age-1+ pollock for the entire surveyed area were 2.64 billion fish weighing 1,341,973 metric tons (t). The majority of the pollock biomass was observed on the continental shelf (84%), Shelikof Strait (5%), near Mitrofania Island (3%), and east of Kodiak Island in Chiniak (2%) and Barnabas Troughs (4%). The majority (86%) of the biomass in the survey area consisted of age-5 fish from the 2012 year class. Compared to previous summer GOA surveys, fish weight at length was similar, but length at age was slightly smaller. Backscatter was attributed to species other than pollock when trawl verification, differentiation based on backscatter frequency response, or other methods allowed. Abundance and biomass estimates were calculated for Pacific ocean perch (Sebastes alutus; 305.9 million fish weighing 172,388 t), and backscatter distribution and abundance relative to previous surveys was estimated for euphausiids (primarily consisting of Thysanoessa inermis, but also including T. spinifera, T. raschii, and Euphausia pacifica).

Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center"s (AFSC) Resource Assessment and Conservation Engineering (RACE) Division conducted an acoustic-trawl (AT) stock assessment survey of

Eastern Bering Sea shelf walleye pollock (Gadus chalcogrammus) midwater abundance and distribution were assessed using 3 Saildrone autonomous vehicles due to Covid-19 restrictions.

Eastern Bering Sea shelf walleye pollock (Gadus chalcogrammus) midwater abundance and distribution were assessed using 3 Saildrone autonomous vehicles due to Covid-19 restrictions.

Eastern Bering Sea shelf walleye pollock (Gadus chalcogrammus) midwater abundance and distribution were assessed using 3 Saildrone autonomous vehicles due to Covid-19 restrictions.