NOAA Ship Oscar Elton Sette Providing Vital Support for Monitoring of Hawaiian Monk Seals and Cetaceans in the Northwestern Hawaiian Islands

August 20, 2007
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Chad Yoshinaga and Molly Timmers preparing the boat to transport gear and personnel from Kure atoll to the NOAA ship Oscar Elton Sette.

The NOAA Ship Oscar Elton Sette will be at sea for 23 days on a cruise to support Pacific Islands Fisheries Science Center (PIFSC) staff engaged in marine mammal research and monitoring in the Northwestern Hawaiian Islands (NWHI).

The primary focus of scientists in the PIFSC Protected Species Division's Marine Mammal Research Program (MMRP) is to monitor the status of the endangered Hawaiian monk seal population, conduct research to better understand factors affecting abundance of the seals, and find ways to enhance population recovery. To this end, MMRP establishes seasonal field camps at the six major monk seal breeding locations in the NWHI. During the current voyage, the Sette will pick up field personnel and equipment from camps at 6 sites where seasonal operations have been completed (French Frigate Shoals, Laysan Island, Lisianski Island, Pearl and Hermes Reef, Midway Atoll, and Kure Atoll) and conduct seal censuses at 2 other sites where no camp has yet been established (Nihoa Island and Necker Island). Under the direction of Chief Scientist Chad Yoshinaga, cruise personnel will load all equipment and supplies from the remote islands onto the ship, materials which have supported teams of 3-4 scientists for 4 months. Included are tents, stoves, solar arrays, computers, leftover food, small boats, and more. Everything brought ashore must be transported by hand and shuttled via small boats from the islands to the ship.

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Spinner dolphin

MMRP scientists will spend a day each at Necker and Nihoa Islands to count seals, document tagged seals, and apply identification tags to weaned seal pups. Identifying seals with tags at these two NWHI locations is important to MMRP research, as these islands are close to the Main Hawaiian Islands (MHI). Subsequent sightings of the tagged seals will provide valuable information on the extent of seal movements between the NWHI and the MHI, something currently unknown.

Besides its monk seal studies, the MMRP is becoming increasingly involved in cetacean research in Hawaii, and to support this project scientists on the Sette will conduct sighting surveys of cetaceans at the sea surface while the ship is en route between islands. They will also recover a High-frequency Acoustic Recording Package (HARP) instrument at Ladd Seamount and replace it with a new HARP. The HARP collects data on underwater sounds from various sources, including vocalizations of cetaceans. Analysis of the HARP data will provide valuable information on the local occurrence and habits of cetaceans and help supplement observations from the sighting surveys.

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Hawaiian monk seal

The cruise will also provide support for several partner agencies working in the NWHI. Supplies and equipment will be transported for the U.S. Fish and Wildlife Service, which maintains stations at French Frigate Shoals and Midway Island and a permanent field camp at Laysan Island. The cruise will also recover a field camp operated by the State of Hawaii Division of Forestry and Wildlife at Kure Atoll.

Shipboard personnel will also collect oceanographic data on subsurface ocean temperature and conductivity periodically during the cruise by taking 'CTD' measurements. At selected stations, the CTD instrument will be launched from the ship. Trailing a thin copper wire connected to computers on the ship, the instrument will measure water Conductivity, Temperature, and Depth (hence the name 'CTD') as it sinks and transmit the data over the wire back to the ship. The data will be added to a comprehensive NOAA oceanographic database and used to better understand large-scale phenomena like climate change and the dynamics of local features like oceanic fronts.