EK60 Water Column Sonar Data Collected During SE1104

Kona Integrated Ecosystem Assessment Survey (SE1104, EK60). This cruise accomplished the following objectives: Oceanographic data were collected from a total of 25 CTD casts while continuous TSG and ADCP measurements were taken along a predefined grid off the west coast of Hawaii to assess the influence of physical dynamics on the region's biological productivity. CTD-mounted fluorometer measurements were carried out by two fluorometers. Chlorophyll was measured for ten discrete samples per CTD using a bench top Turner 10-AU fluorometer. Water samples were preserved for post-cruise flow cytometry to determine phytoplankton size structure. Biological backscatter was monitored using the EK60 echosounder system, both during trawl operations and along 17 acoustic transects (including at least one daytime and one nighttime transit of each transect). Twelve nighttime oblique mid-water trawls were conducted, with replicate trawls at each of six sites. These trawls all targeted the shallow sound scattering layer. Data on cetacean distribution, school size, and school composition were collected with a towed passive acoustic array on 14 transects, including both a daytime and nighttime transit of each transect. Daytime visual cetacean surveys were conducted to help develop habitat envelope models for the Kona region. Fourteen casts of a DIDSON imaging sonar were conducted to collect high resolution information on the density of high sonic scattering layers.