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Tuesday, October 15, 2019. 1:00PM. Webinar: Spatiotemporal variation in the vertical distribution of eastern Bering Sea walleye pollock and implications for gear availability. Cole Monnahan, University of Washington. Sponsored by NOAA’s Alaska Fisheries Science Center. More information here. 

Accurate estimates of distributions of semi-pelagic species requires accounting for changes in vertical distribution because acoustic (AT) and bottom trawl (BT) gears both have vertical blind zones. We resolve this issue by explicitly modeling vertical distribution of eastern Bering Sea walleye pollock (Gadus chalcogrammus) in an index standardization, using both BT and AT data simultaneously, with a feature we added to the VAST software. Annual availability was variable for AT (35-93%) and BT (49-92%) from 2007-2018 and indicated that both survey types provide distinct, but overlapping, information about the spatiotemporal vertical distribution of semi-pelagic fishes.