NOAA Cetacean Survey Underway in the Western Pacific

January 20, 2010

For the next few months, scientists from the Pacific Islands Fisheries Science Center will be conducting a variety of studies in waters of the Mariana Archipelago and other areas of the western Pacific in support of the NOAA ecosystems science mission. Included are research on coral reef ecosystems, cetacean populations, and ocean acidification. The studies will be conducted primarily from the NOAA Ship Oscar Elton Sette.

Cetaceans will be surveyed and plankton will be 
        sampled along this oceanic trackline while the NOAA Ship <em>Oscar Elton Sette</em> is in transit from Hawaii 
        to Guam.  Underwater acoustic recorders will be installed at Wake Island and near Guam to monitor cetaceans in 
        local waters.  Colored lines are boundaries of the 200-mile Exclusive Economic Zones (EEZ).
Cetaceans will be surveyed and plankton will be sampled along this oceanic trackline while the NOAA Ship Oscar Elton Sette is in transit from Hawaii to Guam. Underwater acoustic recorders will be installed at Wake Island and near Guam to monitor cetaceans in local waters. Colored lines are boundaries of the 200-mile Exclusive Economic Zones (EEZ).

The expedition begins with a transit of the Sette from Honolulu, the ship's home port, to Guam from 20 January to 6 February. During the 3315 nautical mile transit, the Sette's scientific crew will undertake several studies in a region seldom visited by research vessels. While the ship is underway, observers stationed on the flying bridge will scan the sea surface looking for cetaceans using 25x150 "big-eye" binoculars. When they encounter a pod (group) of cetaceans, they will identify the species involved and collect data on the size of the pod and its behavior. In addition, they will take photographs for identification purposes and collect biopsy samples. The data will be used for studies on cetacean population structure and abundance

The Sette will record sounds emitted by cetaceans along the survey trackline using a 4-element hydrophone array towed behind the ship. This acoustic data will be used in conjunction with observers' sighting data for species identification studies. Sonobuoys may be deployed to collect additional low frequency acoustic data from large baleen whales.

The Sette will pause at Wake Island during the journey to deploy a High-frequency Acoustic Recording Package (HARP). A second HARP will be deployed when the vessel reaches waters around Guam. Placed at depths of 600-800 meters (1800-2400 feet), the HARPs record acoustic signals produced by cetaceans; the data are vital to long-term monitoring of cetacean presence and activity at these locations.

In addition to surveying cetaceans, during the ocean crossing the scientific crew will routinely collect data on the vertical distribution of ocean conductivity and temperature by deploying a CTD instrument, measure the density of potential cetacean prey (small fish and other marine organisms) in the water column using sonar (backscatter data), and test a Continuous Plankton Recorder (CPR), towed behind the Sette, to assess the surface distribution and composition of plankton in near-surface waters along the transit line.

High-powered binoculars are used to spot cetaceans at the sea surface.
High-powered binoculars are used to spot cetaceans at the sea surface.

Scientific operations during the Honolulu-Guam transit will be directed by PIFSC researcher Erin Oleson of the Cetacean Research Program, part of the Center's Protected Species Division. Besides NOAA researchers from PIFSC, the scientific field party will include colleagues from the NOAA Southwest Fisheries Science Center, the University of Hawaii Joint Institute for Marine and Atmospheric Research, Scripps Institution of Oceanography (University of California San Diego), Alaska Pacific University, and Ocean Associates (contractor).