Cetacean Survey Underway at Palmyra Atoll

October 20, 2011

On October 20, 2011, the NOAA Ship Oscar Elton Sette embarked on a study to learn more about whales and other cetaceans at Palmyra Atoll. The Palmyra Cetacean and Ecosystem Survey 2011 cruise will survey waters within the 200-mile U.S. EEZ surrounding the atoll. The overall objective of the cruise is to estimate the local abundance of dolphins and whales and understand their distribution in the area. In addition, scientists on the Sette will collect biological and oceanographic data to better characterize the environment and ecology of the cetaceans. At the end of the 30-day expedition, the Sette will return to her home port at Ford Island in Pearl Harbor.

The abundance, distribution and stock structure of several cetacean species, like these melon-headed 
        whales, will be studied at Palmyra Atoll.
The abundance, distribution and stock structure of several cetacean species, like these melon-headed 
        whales, will be studied at Palmyra Atoll.
The abundance, distribution and stock structure of several cetacean species, like these melon-headed whales, will be studied at Palmyra Atoll.

The scientific field party includes NOAA researchers from the Pacific Islands Fisheries Science Center (PIFSC), Southwest Fisheries Science Center, and Pacific Islands Regional Office and researchers from NOAA contractors and the University of Hawaii Joint Institute for Marine and Atmospheric Research (JIMAR). Under the leadership of Marie Hill, a PIFSC-affiliated JIMAR scientist, the team will conduct a visual line-transect cetacean survey around Palmyra Atoll. As the ship moves along each survey transect, the scientific field party will use high-powered binoculars to sight, identify and count cetaceans. Data on cetacean distribution, school size, and school composition will be collected to determine abundance. When conditions permit, scientists on the Sette or deployed in small boats will collect cetacean skin samples for biopsy; biopsy results will provide a database for investigations of cetacean stock structure and phylogenetic relationships. Photographs of cetaceans will be taken to document the geographic variation in dolphin morphology and pigment patterns and distribution of individual large whales.

There will be a focused effort to conduct photo-identification and biopsy sampling by small boat around Palmyra Atoll and neighboring Kingman Reef. Species such as melon-headed whales (see accompanying photos), bottlenose dolphins, spinner dolphins, killer whales, and beaked whales are known to occur at Palmyra Atoll. Some species are found there year-round while others are seen only seasonally or occasionally. Less is known about cetaceans at Kingman Reef. In order to investigate this further, the field party will deploy a HARP (High-frequency Acoustic Recording Package) on the seafloor. This instrument will remain there for a year and record all sounds including cetacean vocalizations. From these recordings, researchers will be able to assess the diurnal and seasonal occurrences of cetacean species at Kingman Reef.

Throughout the cruise, oceanographic data will be collected to characterize cetacean habitat and its variation over time. And while most survey staff will be focused on sighting cetaceans, a pair of observers on the Sette will be assigned to collect visual information on seabirds in the area.