Cetacean Ecology Survey Underway in the Northwestern Hawaiian Islands

May 7, 2013
A group of rapidly-surfacing Fraser's dolphins, one of many species that may be observed during the Papahānaumokuākea 
                 Associated Cetacean Ecology Survey, demonstrate the leaping and splashing that serve as visual cues to observers using high-powered 
                 binoculars on the flying bridge of the NOAA Ship Oscar Elton Sette (shown in background).
A group of rapidly-surfacing Fraser's dolphins, one of many species that may be observed during the Papahānaumokuākea Associated Cetacean Ecology Survey, demonstrate the leaping and splashing that serve as visual cues to observers using high-powered binoculars on the flying bridge of the NOAA Ship Oscar Elton Sette (shown in background).
Small boat launches allow closer approaches to cetaceans, so that biopsy samples and photo-identification images can be collected.  
                 The notches on the trailing edge of the dorsal fin of the false killer whale on the right form a unique pattern, allowing this individual to be 
                 identified each time it is photographed.
Small boat launches allow closer approaches to cetaceans, so that biopsy samples and photo-identification images can be collected. The notches on the trailing edge of the dorsal fin of the false killer whale on the right form a unique pattern, allowing this individual to be identified each time it is photographed.
Tracklines (green zig-zags) that the NOAA Ship Oscar Elton Sette will follow during the Papahānaumokuākea 
                 Associated Cetacean Ecology Survey.  The yellow line is the boundary of the Papahānaumokuākea Marine National Monument, 
                 and the white line encloses the U.S. Exclusive Economic Zone around the Hawaiian Islands.
Tracklines (green zig-zags) that the NOAA Ship Oscar Elton Sette will follow during the Papahānaumokuākea Associated Cetacean Ecology Survey. The yellow line is the boundary of the Papahānaumokuākea Marine National Monument, and the white line encloses the U.S. Exclusive Economic Zone around the Hawaiian Islands.

One of the key missions of NOAA is to improve our understanding of the distribution, abundance, and ecology of whales and dolphins in the central and western Pacific Ocean. Such research informs critical decisions on the management of fisheries and other human activities to promote the conservation of these cetacean populations. To advance our understanding or these important marine mammals, the Cetacean Research Program of the Pacific Islands Fisheries Science Center’s (PIFSC) Protected Species Division is conducting the Papahānaumokuākea Associated Cetacean Ecology Survey (PACES) from 7 May to 5 June 2013. The goal of PACES is to survey the waters around the Northwestern Hawaiian Islands (NWHI) within the Papahānaumokuākea Marine National Monument (PMNM) in order to learn more about the abundance, stock structure, range, and habitat of whales and dolphins in this region.

PACES will be conducted aboard the NOAA Ship Oscar Elton Sette and will involve several operations designed to meet the study objectives. The PACES scientific team consists of researchers from PIFSC and several collaborating institutions. Chief Scientist for the PACES expedition is PIFSC ecologist Dr. Amanda Bradford.

A team of visual and acoustic observers will watch and listen, respectively, for cetaceans while the ship travels along predetermined transect lines that representatively cover cetacean habitat within the PMNM ranging from Nihoa Island in the southeast to Pearl and Hermes Atoll in the northwest part of the monument. Visual observers stationed on the ship's flying bridge will sight cetaceans use high-powered binoculars. Acoustic observers will collect information on cetacean presence using a hydrophone array. The data recorded during this line-transect survey will provide information on cetacean density, distribution, and group size and composition and will be used to estimate the abundance of species observed in the study area. When weather conditions and animal behavior permit, a small boat will be launched from the Sette so that groups of some species can be approached more closely by the scientists. During these closer approaches, small tissue samples will be collected from individual cetaceans so that the stock structure and phylogenetic relationships within species can be explored. Photographs will be taken so that marked individuals can be identified and geographic variation in morphology and coloration can be documented. Satellite tags will be attached to some individuals, so that their location can be tracked and their movement patterns and range are better understood. Oceanographic and active acoustic data will be collected along the PACES transects, which will allow for an assessment of the environmental conditions and prey availability encountered by cetaceans in the PMNM.

Focused surveys using a small boat launched from the Sette will occur on 3-4 days around some of the NWHI, potentially Nihoa, French Frigate Shoals, Gardner Pinnacles, and Pearl and Hermes. These small-boat surveys will provide scientists greater access to cetaceans in the nearshore waters of selected islands and atolls. Some cetacean species in the main Hawaiian Islands (MHI) are known to exist as separate island-associated and pelagic stocks, and it is possible that this stock structure also occurs in the NWHI. Data provided through biopsy sampling, photo-identification, and satellite tagging of individuals in nearshore waters will offer insight into stock differentiation between the NWHI and pelagic regions, as well as between the NWHI and MHI.

Since 2009, a High-frequency Acoustic Recording Package (HARP) has been deployed with few interruptions in the southeast corner of Pearl and Hermes. The HARP allows for long-term acoustic monitoring of cetacean presence and occupancy in the area. That HARP will be retrieved and a new one deployed during PACES. A new acoustic device, referred to as a Compact Acoustic Recording Buoy (CARB), is being used for the first time in the Pacific Islands Regions during PACES. The CARB will be used for short-term acoustic recording of encountered cetaceans and will be deployed from either the Sette or the small boat.