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Cetacean and Seabird Data Collected During the Mariana Archipelago Cetacean Survey (MACS), May–July 2021

June 06, 2022

A Mariana Archipelago Cetacean Survey (MACS) 2021 shipboard survey project for cetaceans and seabirds around the Mariana Archipelago.

In summer 2021, the Pacific Islands Fisheries Science Center conducted a comprehensive line-transect survey for cetaceans and seabirds within the United States exclusive economic zones of Guam and the Commonwealth of the Northern Mariana Islands. The Mariana Archipelago Cetacean Survey (MACS) 2021 project was part of the multi-year Pacific Marine Assessment Program for Protected Species (PacMAPPS) plan to conduct surveys and estimate density for cetacean species in regions of joint NOAA Fisheries, Bureau of Ocean Energy Management, and U.S. Navy interest.

MACS 2021 sailed for 59 days at sea aboard the NOAA Ship Oscar Elton Sette in May–July, 2021, and surveyed 8,711.7 km of trackline. The team conducted visual and passive acoustic surveys during daylight hours when weather permitted. There were 77 cetacean sightings of at least 12 species. The most frequently sighted species during the project were sperm whales, false killer whales, and pantropical spotted dolphins . Approximately 2,300 photos of 9 cetacean species were collected for individual or species identification during 20 cetacean sightings. Two biopsy samples were collected from false killer whales.

During towed array surveys there were 245 acoustic detections of cetaceans, of which 47 were linked to visually sighted groups. Twenty-two Drifting Acoustic Spar Buoy Recorders were deployed and recovered throughout the survey area and will contribute additional information on beaked whale, and baleen whale distribution and abundance. The seabird observers counted 3,266 individual birds in 1,605 seabird sightings among 29 species. The most frequently sighted seabird species included the Sooty Tern, Short-tailed Shearwater, and Red-footed Booby. Sixty-eight feeding flocks were observed. Oceanographic sampling was conducted with twice daily CTD casts when conditions permitted, with a total of 79 casts throughout the survey area.


Yano KM, Hill MC, Oleson EM, McCullough JLK, Henry AE. 2022. Cetacean and seabird data collected during the Mariana Archipelago Cetacean Survey (MACS), May -July 2021. U.S. Dept. of Commerce, NOAA Technical Memorandum NOAA-TM-NMFS-PIFSC-128, 59 p.  https://doi.org/10.25923/7pbh-zq68.

Last updated by Pacific Islands Fisheries Science Center on 06/13/2022

Cetacean Surveys Mariana Islands