EK80 Water Column Sonar Data Collected During DSB1

Patterns in acoustically derived biological scatter through the water column were collected with multi-frequency scientific echosounders (Simrad EK80) operating at 18kHz, 38kHz, 70kHz and 120kHz following protocols developed during the NOAA NRDA DAP data collection operations. Specifically, during each cruise, transducers were installed on a rigid pole mounted to the side of the ship, and calibrated at sea for operating conditions following protocols developed during the ONSAP/DAP cruises. The dynamics of the mesopelagic scattering community will be examined through the depth dependent scattering responses at both frequencies (18 and 38kHz) as well as through the difference between the mean volume backscattering strength (MVBS; in dB) at 18 kHz and 38 kHz (dMVBS(18-38)). In addition, scatterers in the upper water column (~150m) will be examined by analyzing the all four available frequencies.