| Water Column Sonar Data Collection (SH1610, ME70) |
| 1. Use paired midwater trawls to evaluate potential selectivity of Pacific hake age/size
classes by different codend liners (Standard AWT 32 mm versus 7 mm used by DFO on
their Cantrawl) in the Aleutian wing trawl 24/20 (AWT). Midwater trawling for this
research will take place on all three survey legs. 2. Use paired trawls to evaluate
performance of net with and without the marine mammal excluder installed. 3. Test
a larger kite on the AWT for stability and ease of use with headrope sensors. 4. Continuously
sample multi-frequency acoustic backscatter data using the ship?s Simrad EK60, EK80,
and ME70 scientific echo sounder systems to estimate the distributions and abundances
of hake, myctophids, gelatinous zooplankton, and krill. 5. Conduct research using
the EK80 to distinguish between hake, myctophids, and rockfish. Compare EK80 backscatter
signature with that of the EK60. 6. Optically observe fish behavior inside daytime
trawls using a video or stereo camera and lights mounted inside the net. Test stereo
camera system for quantifying fish species and length. 7. Collect a variety of other
acoustic, biological, and oceanographic samples to characterize the biotic and abiotic
environments and predator-prey interactions of the surveyed species. 8. Investigate
near-field calibration techniques. 9. Use night operations time to conduct hydrographic
measurements with a CTD. A NWFSC dissolved O2 sensor will also be mounted on the CTD.
10. Sample profiles of temperature and salinity using an underway conductivitytemperature-depth
(CTD) system during daytime operations. 11. Continuously sample air temperature, barometric
pressure, and wind speed and direction using the ship?s integrated weather station. |
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