EK60 Water Column Sonar Data Collected During FR0904

Sardine Biomass Survey. Eighty four primary stations were plotted on the survey track with an approximate spacing of 20 - 40 nautical miles. At each station the following activities were performed: a. Deployment of a Seabird CTD down to 200 meters, bottom depth permitting. The self-contained CTD collected depth, temperature, conductivity and oxygen data. b. Standard Pairovet cast down to 70 meters depth deployed concurrently with the CUFES system. c. A CalBOBL (CalCOFI Bongo) standard oblique plankton tow with 300 meters of wire out, depth permitting, using paired 505 µm mesh nets with 71 cm diameter openings. The technical requirements for this tow were: Descent wire rate of 50 meters per minute, held at terminal depth for 30 seconds and retrieved at a wire rate of 20 meters per minute. All tows with ascending wire angles lower than 38° or higher than 51° in the final 100 meters of wire were repeated. Additionally, a 45° wire angle was closely maintained during the ascent and descent of the net frame. d. Standard meteorological data including SST, wind speed and direction, wave height and direction, cloud cover, relative humidity, air temperature and barometric pressure. e. During all transits between stations continuous measurements were made of pelagic fish eggs (CUFES) and acoustic targets using the EK-60. f. A 264 Nordic Rope Trawl with 3.0 meter² foam core doors was towed on the surface at night for a duration of thirty minutes. The 264 NRT was modified for surface trawling with Polyform floats attached to the head rope and trawl wings. The trawls have been modified with marine mammal excluder devices (MMED) to eliminate any possibility of catching marine mammals. Although the probability was very low that the gear being lowered into the water on station will interact with any marine mammals, a marine mammal watch was initiated 30 minutes before arriving on station. If any marine mammals were detected in the area, operations were suspended and the station location moved.