FISH 250: Sonar and CTD

About this Cruise

This month-long cruise aboard the NOAA Ship Oscar Elton Sette brings together six diverse teams to survey fish populations using non-catch methods. Traditionally, fish populations have been assessed by catching fish, visiting fish markets and interviewing fishermen. Chief Scientist Scott Ferguson hopes to support Guam and the CNMI in monitoring their natural resources using non-extractive methods. The ship will also use multibeam sonar to map areas that are important fishery resources hopefully to include Galvez Bank, offshore slopes near Rota, and the banks of Farallon de Medinilla.

The survey methods include BotCams and BRUVs, two systems that put baited cameras on the bottom, and a TOAD which is a camera towed near the seafloor . An Autonomous Underwater Vehicle will travel on its own via computer programming and bring back photographs and video. Additionally, acoustic methods will be used to survey fish in the water column.

This expedition brings together scientists from NOAA’s Pacific Islands Fisheries Science Center and Northwest Fisheries Science Center, as well as the University of Hawaii’s Joint Institute for Marine and Atmospheric Research, the University of Guam Marine Lab, and Woods Hole Oceanographic Institution.

Friday, February 12, 2010

Sonar and CTD

Left: Jeff & Jonathan prepare the CTD

Right: Retrieving the CTD (check the feet)

All day Friday, all night, and into Saturday has been spent with the multibeam sonar collecting data and mapping the area of study. The “fish people” need an idea of the bottom contours to decide where to put the cameras. Yesterday afternoon, the scientists used a CTD tool to measure conductivity, temperature and density. The results of this test were used by the map makers to most effectively use the sonar data for accurate maps. Currently the camera crew is preparing to launch 5 sets of cameras. The BotCam (bottom camera bait station) has an anchor and floatation that will keep it a few feet above the bottom. The BRUVs (Baited Remote Underwater Video) will sit directly on the bottom. We should have fish data later tonight but, 10 cameras will make a lot of video to watch.