Study off Kona Coast of Hawai'i Focused on Habitat and Behavior of Small Whales

July 10, 2008
Pilot whales swimming near the <em>Oscar Elton Sette</em> off the island of Hawai'i
Pilot whales swimming near the Oscar Elton Sette off the island of Hawai'i

During July 2008, NOAA's Pacific Islands Fisheries Science Center (PIFSC) will lead a research expedition off the Kona Coast of island of Hawai'i, in the main Hawaiian Islands. Participating scientists from the University of Hawai'i, Cascadia Research Collective, Woods Hole Oceanographic Institution, Wild Whale Research Foundation, and Duke University will investigate the biology and behavior of some of the most poorly-understood whale species and learn more about how these deep-diving marine mammals dive, feed, interact with one another and respond to sounds in their environment. Directing the cruise will be Chad Yoshinaga of PIFSC and Marie Chapla of the University of Hawaii Joint Institute for Marine and Atmospheric Research.

Using a pole, a researcher deploys a d-tag (with suction cups) on a pilot whale
Using a pole, a researcher deploys a d-tag (with suction cups) on a pilot whale

Conducting operations from the NOAA Ship Oscar Elton Sette and smaller boats launched from the Sette, scientists will place monitoring tags ("d-tags") on deep-diving beaked whales, pilot whales, and melon-headed whales. The tags are equipped with VHF transmitters to allow radio tracking of the whales when they are at the sea surface. Attached to the whales by suction cups, some of the tags will record very detailed information over brief time intervals about how the whales move and what sounds they make and hear. Other monitoring tags will provide geographical data over a longer time span on movements of the whales around the Hawaiian Islands.

In addition to deploying the monitoring tags, scientists will collect a variety of environmental data to help analyze the whales' movements in relation to physical characteristics of their surroundings and their prey. They will deploy a CTD instrument at several sites along the coast to measure how the ocean's conductivity (salinity) and temperature vary with depth, geographical location, and time. Sonar (acoustics) equipment on the Sette will be used to collect "backscatter" data that will be analyzed to measure the density of small fish and crustaceans in the water column that are important to the whales as potential prey. The acoustics data will reveal how prey density changes from day to night and with distance from shore.

The environment of whales will be studied off the Kona Coast of the island of Hawai'i, in the main 
    Hawaiian Islands.  The cruise plan calls for prey density to be measured along a pair of sonar transects perpendicular to the coast and 
    a CDT instrument to be deployed at 5 locations.  Survey dates are tentative. The map also shows depth contours in the study area (in 
    meters).
The environment of whales will be studied off the Kona Coast of the island of Hawai'i, in the main Hawaiian Islands. The cruise plan calls for prey density to be measured along a pair of sonar transects perpendicular to the coast and a CDT instrument to be deployed at 5 locations. Survey dates are tentative. The map also shows depth contours in the study area (in meters).

When conditions allow, biopsy samples will be collected from the whales to ascertain their genetic makeup and ID photographs of them will be taken. The genetics and photo-ID information will improve understanding of cetacean population structure.

The Sette scientific expedition will be carried out concurrently and in coordination with operations of the U.S. Navy and other fleets participating in Rim of Pacific (RIMPAC) training exercises. By analyzing data collected during the cruise, scientists can gain a better understanding of how the various species of deep-diving whales behave naturally in their environment and what factors influence their behavior, including operational sounds produced during naval exercises.