2011 California Current Ecosystem Survey. Split-beam echosounder data were collected at four-frequencies (38, 70, 120, and 200 kHz on Frosti; and 18, 38, 70, 120, and 200 kHz on Shimada), throughout the Spring 2011 CCE survey. On Shimada, the EK60-trigger pulse from the 38, 120, and 200 kHz EK60s was used to synchronize the transmissions of the three echosounders with the 18 and 70 kHz EK60s and the RDI 75-kHz Ocean Surveyor ADCP. Except for these acoustic systems, all other echosounders, speed logs, and sonars operating at or near the survey frequencies were secured during survey operations. Exceptions were made during stations when the Doppler velocity log was operated, and in shallow regions when bridge echosounders (50 and 200-kHz Furuno) were operated. The ME70 was set as slave triggered by the EK60 pulse, with a delay of 340 ms. On Shimada, 1024-µs pulses of the 38, 120, and 200 kHz frequencies were transmitted simultaneously with a one second ping interval to a depth of 250 m. The 18 and 70 kHz echosounders EK60s were configured to record to 1000 m, which required a longer ping interval. The 18 and 70 kHz GPTs were triggered by the 120 kHz GPT, but the operating range resulted in a ping interval of two seconds for these two frequencies. The ME70 was operated using the configuration ‘Beams27_BW10deg_Grp3_Overlap3_Sector100deg_Ref0’ designed by SWFSC. The exception being on 22 Apr, for 20 min. during station work in shallow water (83.3-40.6) when the ME70 was operated using the configuration ‘Grc0525_x3_pulse1536’ with 25 beams spanning 160°. Raw ME70 data were stored to files with the prefixes ‘ME1104SH’ and ‘CONFIGTEST’ for the ‘Beams27…’ and ‘Grc0525_x3…’ configurations. The operational range and recording range were 250 m, and transmission interval was 1 s. Differential-corrected position data for the ME70 were supplied by the MX Marine MX420 GPS, heading data were from the ship’s gyro, and motion data were from the POS-MV. The transducer offsets were set to distances between transducer and POS-MV IMU (0.60, -0.72, 1.08 m in x, y, and z directions). The ME70 GPS offset values were set to zero for all. These zero offset values appear to correspond to the POS-MV antennas and therefore POS-MV position, but not to the MX420 position. Hence it appears necessary to apply 17.250 and 1.00 m alongship and athwartship offset values to the ME70 position data to accurately place the samples.