We assembled approximately 230,000 National Ocean Service (NOS) bathymetric soundings from 39 lead-line and single-beam echosounder hydrographic surveys conducted from 1896 to 2005 in Norton Sound, Alaska. These bathymetry data are available from the National Geophysical Data Center (NGDC: http://www.ngdc.noaa.gov), which archives and distributes data that were originally collected by the NOS and others. While various bathymetry data have been downloaded previously from NGDC, compiled, and used for a variety of projects, our effort differed in that we compared and corrected the digital bathymetry by studying the original analog source documents - digital versions of the original survey maps, called smooth sheets. Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum. We incorporated 3 multibeam surveys, and added an additional 6,992 single-beam soundings from the 2010 Northern Bering Sea bottom trawl survey to fill in where smooth sheet data was lacking. We proofed and digitized 312 cartographic features, comprised mostly of rocks and islets and also digitized 4,305 verbal sediment descriptors, and digitized or adapted 2,142 km of mainland and 837 km of island shoreline.

We assembled approximately 230,000 National Ocean Service (NOS) bathymetric soundings from 39 lead-line and single-beam echosounder hydrographic surveys conducted from 1896 to 2005 in Norton Sound, Alaska. These bathymetry data are available from the National Geophysical Data Center (NGDC: http://www.ngdc.noaa.gov), which archives and distributes data that were originally collected by the NOS and others. While various bathymetry data have been downloaded previously from NGDC, compiled, and used for a variety of projects, our effort differed in that we compared and corrected the digital bathymetry by studying the original analog source documents - digital versions of the original survey maps, called smooth sheets. Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum. We incorporated 3 multibeam surveys, and added an additional 6,992 single-beam soundings from the 2010 Northern Bering Sea bottom trawl survey to fill in where smooth sheet data was lacking. We proofed and digitized 312 cartographic features, comprised mostly of rocks and islets and also digitized 4,305 verbal sediment descriptors, and digitized or adapted 2,142 km of mainland and 837 km of island shoreline.

We assembled approximately 230,000 National Ocean Service (NOS) bathymetric soundings from 39 lead-line and single-beam echosounder hydrographic surveys conducted from 1896 to 2005 in Norton Sound, Alaska. These bathymetry data are available from the National Geophysical Data Center (NGDC: http://www.ngdc.noaa.gov), which archives and distributes data that were originally collected by the NOS and others. While various bathymetry data have been downloaded previously from NGDC, compiled, and used for a variety of projects, our effort differed in that we compared and corrected the digital bathymetry by studying the original analog source documents - digital versions of the original survey maps, called smooth sheets. Our editing included deleting erroneous and superseded values, digitizing missing values, and properly aligning all data sets to a common, modern datum. We incorporated 3 multibeam surveys, and added an additional 6,992 single-beam soundings from the 2010 Northern Bering Sea bottom trawl survey to fill in where smooth sheet data was lacking. We proofed and digitized 312 cartographic features, comprised mostly of rocks and islets and also digitized 4,305 verbal sediment descriptors, and digitized or adapted 2,142 km of mainland and 837 km of island shoreline.

The acoustic trawl database for Frederick Sounds echo-trawl survey was conducted from 2001 to 2004. The surveys were conducted throughout most of the southern part of Stephens Passage and Frederick Sound in southeast Alaska and all their adjoining bays. Acoustic and trawl surveys were conducted every 3 months to verify acoustic signals and to collect biological data. This study was conducted to study the relationship between Steller sea lions (Eumetopias jubatus) and their prey. Acoustic equipment were calibrated before every trawl survey. Trawls were used to identify the fish species associated with a specific acoustic signal and to get length weight data per species. Acoustic data were analyzed by the same qualified acoustician throughout the surveys duration with calibrations entered into the analytical software after each calibration. Trawl data were used to enumerate and identify all nekton found within the study area and to generate length frequencies, species composition and abundance by season. The acoustic data was use to generate biomass estimates for Pacific herring, Pacific hake and walleye pollock. Longlines were deployed to better identify and enumerate the benthic species not usually caught in pelagic trawls.

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 routinely conduct acoustic-trawl (AT) stock assessment surveys in the Gulf of Alaska (GOA) during late winter and early spring to estimate the distribution and abundance of walleye pollock (Theragra chalcogramma). Historically, most of these efforts have been focused on the Shelikof Strait area, which has been surveyed annually since 1980, except in 1982 and 1999. The Shumagin Islands area has also been surveyed annually since 2005 with prior surveys in 1994-1996 and 2001-2003. Additionally, the GOA continental shelf break east of Chirikof Island to Barnabas Trough has been surveyed annually since 2002. In 2010, survey activities were expanded to include Morzhovoi Bay, Pavlof Bay, the bays along the southern coast of the Kenai Peninsula, and Prince William Sound. This report presents the distribution and abundance of walleye pollock for all AT surveys conducted in the GOA during February and March 2010 along with acoustic system calibration and physical oceanographic results.

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 acoustic-trawl (AT) stock assessment surveys in the Gulf of Alaska (GOA) during late winter and early spring 2017 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus) within several of their main spawning grounds. These pre-spawning pollock surveys covered the Shumagin Islands, Sanak Trough, and Morzhovoi and Pavlof Bays (DY2017-01; 8-14 February).

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's (AFSC) Resource Assessment and Conservation Engineering (RACE) Division conducted acoustic-trawl (AT) stock assessment surveys in the Gulf of Alaska (GOA) during late winter and early spring 2018 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus) at several of their main spawning grounds. These pre-spawning pollock surveys included the Shumagin Islands, Sanak Trough, Morzhovoi and Pavlof bays (DY2018-01; 5-15 February)