NOAA Ship OSCAR ELTON SETTE just returned from a ten day Highly
Migratory Species Oceanography cruise. The purpose of this cruise was to collect oceanographic data that helps scientists understand how different conditions in the ocean affect highly migratory fish stocks such as tunas and swordfish.

The research was conducted along a line that ran southwest of the island of Oahu from 17 degrees North latitude to 9 degrees North latitude. A CTD, short for conductivity-temperature-depth, cast was done every 30 nautical miles. The instrument used for CTDs weighs about 1000 lbs. and is lowered on a cable by one of our deck winches to 1000 meters below the surface. As the CTD descends it collects data on temperature, depth, salinity, oxygen and chlorophyll levels. The unit also has numerous large bottles attached to it which are remotely triggered by one of the ship's computers to collect samples of water at various depths for further analysis.

Issacs-Kidd midwater trawls were used to collect micronekton and zooplankton at 40 meters and 100 meters below the surface. The net is towed at these depths for about 40 minutes. The small animals collected in the net help the scientists gather information about sea turtle habitats. Tewnty-four tows were done along the ships track line at four different stations.