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2015 Pollock Acoustic/Trawl Survey Gulf of Alaska EK60 Raw Data
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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.
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