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EK80 Water Column Sonar Data Collected During RL1907

Published by NOAA National Centers for Environmental Information | National Oceanic and Atmospheric Administration, Department of Commerce | Metadata Last Checked: January 27, 2026 | Last Modified: 2023-09-12T00:00:00.000+00:00
The survey domain was defined by the modeled distribution of potential habitat for the northern subpopulation (stock) of Pacific Sardine (Zwolinski et al., 2011), and information recently gathered from other research projects [e.g., California Cooperative Oceanic Fisheries Investigations (CalCOFI) samples] or fishing industry reports (e.g., catch and bycatch data). This area encompassed the anticipated distributions of the northern stock of Pacific Sardine and the central and northern stocks of Northern Anchovy off the west coasts of the U.S. and Canada from approximately San Diego, CA, to Cape Scott, British Columbia, but also spanned portions of the southern stock of Pacific Sardine, and stocks of Pacific Mackerel, Jack Mackerel, and Pacific Herring. On Lasker, multi-frequency EK60 General Purpose Transceivers (18-and 38-kHz GPTs; Simrad) and EK80 Wideband Transceivers (70-, 120-, 200-, and 333-kHz WBTs; Simrad) were configured with split-beam transducers (ES18-11, ES38B, ES70-7C, ES120-7C, ES200-7C, and ES333-7C, respectively; Simrad). The transducers were mounted on the bottom of a retractable keel or “centerboard”. The keel was retracted (transducers~5-m depth) during calibration, and extended to the intermediate position (transducers ~7-m depth) during the survey. Exceptions were made during shallow water operations, when the keel was retracted; or during times of heavy weather, when the keel was extended (transducers~9-mdepth) to provide extra stability and reduce the effect of weather-generated noise. Transducer position and motion were measured at 5Hz using an inertial motion unit (Applanix POS-MV, Trimble). Final 2021 Report: https://doi.org/10.25923/dg6w-q452 Final 2021 Biomass Report: https://doi.org/10.25923/nghv-7c40

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