EK60 Water Column Sonar Data Collected During SE1003

Oceanographic Survey in waters of the Northern Mariana Islands, Guam, and Micronesia (SE1003, EK60). The goals of the cruise were to collect acoustic backscatter and oceanographic data at the vicinity of CNMI, Guam, and in the northern part of Micronesia. Data collected consisted of CTD casts, trawl samples, and continuous monitoring of currents and biological acoustic backscatter. CTD cats were conducted at predetermined stations. CTDs were equipped with oxygen sensors and fluorometers, and water was sampled at discrete depths during each cast for nutrients and chloropigment determinations. Trawl operations were conducted at predetermined stations using an Isaacs Kidd midwater trawl at depths of the shallow sound scattering layer. Currents were continuously monitored using an RD Instruments Acoustic Doppler Current Profiler (ADCP) operating at 75 kHz frequency. Biological backscatter was recorded using an EK60 echosounder system along predetermined transects, operating at 38, 70, and 120 kHz frequencies.