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Acoustic Vessel-of-Opportunity (AVO) Index for Midwater Bering Sea Walleye Pollock, 2016-2017
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2019
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Series: AFSC processed report ; 2019-01
[PDF-841.44 KB]
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Description:Walleye pollock (Gadus chalcogrammus, hereafter pollock) is a commercially important gadid fish species and the target of a major trawl fishery on the eastern Bering Sea shelf. The fishery independent time series used to manage this valuable stock include data from two summer surveys conducted by the Alaska Fisheries Science Center. A bottom trawl (BT) survey is conducted annually to assess demersal pollock, as well as other commercially important groundfish and crab species (Conner et al. 2017). An acoustic-trawl (AT) survey is currently conducted biennially (intervals ranged from 1 to 3 years in the past) to assess midwater pollock (Honkalehto et al. in press). In an effort to obtain annual information for midwater pollock, Honkalehto et al. (2011) used acoustic backscatter at 38 kHz collected by BT survey vessels for a portion of the eastern Bering Sea shelf, from near surface to 3 m off bottom, to develop an abundance index that was strongly correlated with the total biennially estimated AT survey pollock biomass (r2 = 0.90, p = 0.001, 2006-2014; Honkalehto et al. 2017). This abundance index from vessels of opportunity (AVO) is estimated annually. It is an important component of the Bering Sea pollock stock assessment because it provides information on midwater pollock in years when the AT survey is not conducted (Ianelli et al. 2016). This report updates and discusses AVO index results for summers 2016 and 2017.
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Rights Information:Public Domain
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