MS70 Water Column Sonar Data Collected During RL1706

During summer 2017, the west coasts of the United States and Vancouver Island, Canada, were surveyed using Lasker during the feeding seasons of sardine and anchovy. The survey departed from San Diego, transited to the northern end of Vancouver Island and sampled southward. Compulsory transects were nearly perpendicular to the coast with nominal separations of 20 nmi in most areas and with nominal separations of 10 nmi in areas where CPS were observed acoustically, in trawl catches, or both. The transect positions also covered much of the potential habitat of sardine at the time of the survey. The survey spanned an area from approximately Cape Scott, British Columbia (northern end of Vancouver Island) to Point Conception, with 105 east-west transects totaling 3540 nmi, and 83 Nordic trawls.

Multi-frequency (18, 38, 70, 120, 200, and 333 kHz) General Purpose Transceivers (Simrad EK60 GPTs) and Wideband Transceivers (Simrad EK80 WBTs) were configured with split-beam transducers (Simrad ES18-11, ES38B, ES70-7C, ES120-7C, ES200-7C, and ES333-7C, respectively). 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 The keel was retracted (transducers ~5-m depth) during calibration, and extended to the intermediate position (transducers ~7-m depth) during the survey. Exceptions were made during shallow water operations, when the keel was retracted; or during times of heavy weather, when the keel was extended (transducers ~9-m depth) to provide extra stability and reduce the effect of weather-generated noise.In addition, acoustic data were also collected using an ME70 multibeam echosounder (Simrad) and MS70 multibeam sonar (Simrad).

Final Summer 2017 Survey Report: https://repository.library.noaa.gov/view/noaa/17367
Final Summer 2017 Biomass Report: https://repository.library.noaa.gov/view/noaa/19808