EK60 Water Column Sonar Data Collected During MF0804

California Current Ecosystem Survey. 1. Each coast-wide survey station included the following:
a. A CTD/Rosette consisting of four 2.5 liter hydrographic bottles lowered to 500 meters
(depth permitting) to measure physical parameters and collect water at discrete depths
for analysis of salinity.

b. A CalBOBL (CalCOFI Bongo) standard oblique plankton tow with 300 meters of wire
out, depth permitting, using a 505 Âµm mesh net paired with a 333 Âµm mesh net 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. . A 45Â° wire angle was closely maintained during the
ascent and descent of the net frame. All tows with ascending wire angles lower than 38Â°
or higher than 51Â° in the final 100 meters of wire were repeated.
c. A Manta net (neuston) tow, using a 505 Âµm mesh net on a frame with a mouth area of
0.133 mÂ². The frame was towed for 15 minutes at a target speed of 60-70 cm/sec or an
angle of stray between 20-25 degrees.
d. Weather observations.
e. A Pairovet (vertical) plankton tow was taken at all stations. The Pairovet net was fished
from 70 meters to the surface (depth permitting) using paired 25 cm diameter 150 Âµm
mesh nets. The technical requirements for Pairovet tows were: Descent rate of 70
meters per minute, held at depth for 10 second duration then an ascent rate of 70 meters
per minute. All tows with wire angles exceeding 15Â° during the ascent were repeated.

f. A surface tow using a Nordic 264 pelagic trawl was conducted during nighttime
operations. Each tow was fished for a 30 minute duration at a towing speed of
approximately 3.5 knots. The catch of each tow was processed in the following manner:
Sardines collected in each trawl were randomly sub-sampled. Standard length and body
weight were measured, otoliths were collected, and ovaries preserved in buffered
formalin. These fish were assigned a maturity code based on a four stage system
developed during a previous Tri-national Sardine Forum. 
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g. During daylight hours marine mammal and seabird observations were conducted
enumerating and identifying all seabirds and marine mammals encountered. Mammals
were not quantitatively surveyed on Leg II.
2. While underway during the coast-wide sardine survey, the following operations were conducted:
a. Directed adaptive sampling of pelagic fish eggs using the following protocol: Water
was continuously sampled using the CUFES (Continuous Underway Fish Egg Sampler)
from a depth of six meters. Approximately 640 liters/minute was sent through a
concentrator which filters all material larger than 505 Âµm. The sieved sample was
collected and identified. All fish eggs were identified to lowest taxa, counted and
entered into the data acquisition software. Each sample entry is coupled with sea surface
temperature, geographical position, wind speed and direction, date and time, and surface
salinity.
Sampling intervals varied in length, depending on the number of fish eggs seen, from
two to sixty minutes with an average interval of thirty two minutes. When two
consecutive samples had a concentration of Pacific sardine eggs equal to or greater than
1 egg per minute, the ship stopped to conduct a Pairovet tow. Pairovet tows continued at
four mile intervals until a concentration of less than one egg per minute was observed in
two consecutive samples. All Pairovet samples were taken concurrently with a CUFES
sample in addition to sampling continuously between Pairovet samples.
b. Once underway, the Freemanâs Acoustic Doppler Current Profiler (ADCP, RDI 150
kHz model) was sampling at all times. Data was periodically backed up to a writable
DVD.
c. Once underway, the scientific sounder (Simrad EK-60, 38, 120, and 200 kHz split beam
transducer) was sampling at all times. Data was periodically backed up to a writable
DVD.
d. Once underway, the Freemanâs thermosalinometer (TSG) was run at all times with the
shipâs Scientific Computing System (SCS) serving as the main data collection system.

Tags: acoustic scattering, acoustic sounders, aquatic ecosystems, aquatic sciences, bathymetry, bathymetry/seafloor topography, benthic, biosphere, doc/noaa/nesdis/ncei, doc/noaa/nesdis/ngdc, doc/noaa/nmfs, earth science, ecosystems, fisheries, in situ/laboratory instruments, marine ecosystems, national centers for environmental information, national geophysical data center, national marine fisheries service, nesdis, noaa, north pacific ocean, ocean acoustics, oceans, pelagic, profilers/sounders, seafloor topography, u.s. department of commerce, vertical location, water column, water column mapping system, wcms
Organization: National Oceanic and Atmospheric Administration, Department of Commerce