The Institute of Cetacean Research
Completion of the 2025 IWC/Japan Joint Cetacean Sighting Survey Cruise in the North Pacific
- IWC POWER
October 6, 2025
Designated Corporation for Scientific Whale Research
THE INSTITUTE OF CETACEAN RESEARCH
1. Background
This survey is conducted jointly by the International Whaling Commission (IWC) and Japan, and is commonly referred to as IWC-POWER (International Whaling Commission/Pacific Ocean Whale and Ecosystem Research). IWC-POWER is the successor of IWC/SOWER (International Whaling Commission Southern Ocean Whale and Ecosystem Research), a successful whale research program acclaimed globally, which was conducted in the Antarctic Ocean from 1996/1997 to 2009/2010. Taking advantage of the know-how, experience and achievements of IWC/SOWER, IWC-POWER has been carried out every summer since 2010 based on the main research plan of the IWC Scientific Committee.
For the past fifteen years, the IWC-POWER research cruises have widely surveyed mainly the Northeast Pacific and have been covering a wide area of the North Pacific that had not been surveyed for several decades, finding large numbers of fin and sei whales in the Gulf of Alaska area north of 40 degrees north latitude and a large number of Bryde’s and sperm whales in waters south of 40 degrees N, and valuable data have been collected to contribute to objective stock assessment of these species. In addition, distribution information on rare species such as blue whales and right whales has also been collected.
This was the 16th research cruise, and with the generous cooperation of the U. S government, a total of four international researchers, two from the U.S. and two from Japan, conducted research from July 22 to October 9 in the in the Arctic Ocean (southern part of the Chukchi Sea: within the U.S. EEZ) and in the central Bering Sea (the area south of 69th parallel N latitude, north of the Aleutian Islands, east of 167° E longitude, and west of the 170° W longitude line).
2. Outline of the 2025 Research Cruise
The IWC-POWER program is conducted collaboratively by the IWC and the Government of Japan. The IWC Scientific Committee has developed the research program and established the IWC-POWER Steering Group (Convenor: Koji Matsuoka, ICR), which has a role of designing the research plan and analyzing the results of the cruises. The survey was commissioned by the Fisheries Agency of Japan and conducted by the Institute in cooperation with the Tokyo University of Marine Science and Technology (TUMSAT), the National Oceanic and Atmospheric Administration/Alaska Fisheries Science Center (NOAA/AFSC), and other related organizations. Many gray whales and fin whales and other whale species were found in the research area. The whales were photographed for identification and biopsy (skin and blubber) samples were collected for DNA analysis. In particular, the gray whale was a high priority species in this year’s survey, and we successfully collected samples from 32 individuals. Detailed results of the research will be presented at the IWC/SC annual meeting and other international organizations (the results introduced here are preliminary figures).
2.1 Main objectives
(1) Collection of information for the in-depth stock assessment of humpback whales and gray whales.
(2) Collection of data on distribution and stock structure of the rare North Pacific right whale.
(3) Collection of data on abundance and stock structure of other whale resources with insufficient resource information.
(4) Collection of basic information, including oceanographic (sea water temperature, marine debris, etc.) necessary for the development of the medium- to long-term plan of this research program.
2.2 Research Cruise Period
From July 22 to October 9, 2025 (80 days)
2.3 Research Area
Waters part of the Chukchi Sea and of the Bering Sea in the U.S. Exclusive Economic Zone (Figure 1). The research vessel called at the port of Dutch Harbor, Alaska, to disembark U.S. researchers and to load and unload survey materials.
2.4 International Researchers
The survey was conducted by the following international researchers appointed by the IWC Scientific Committee.
Hiroto Murase (Cruise leader, Tokyo University of Marine Science and Technology, Japan)
Jessica Crance (Alaska Fisheries Science Center, NOAA/AFSC, USA)
Bernardo Alps (IWC-nominated international researcher, USA)
Isamu Yoshimura (IWC-nominated international researcher, Japan)
2.5 Research Vessel
Yushin-Maru No. 2 (Kyodo Senpaku, Ltd., 747 tons, Captain Chikamasa Ohkoshi, 16 crewmen).
2.6 Total Distance Covered
1,161 nautical miles (approximately 2,150km).
2.7 Main whale sightings
North Pacific right whale (1 group, 1 animal), gray whale (55 groups, 75 animals), fin whale (91 groups, 126 animals), sei whale (16 groups, 69 animals), minke whale (8 groups, 8 animals), humpback whale (50 groups, 68 animals), sperm whale (10 groups, 18 animals), killer whale (9 groups, 45 animals).
2.8 Results of sample collection and other experiments
(1) Photo identification data (number of individuals)
North Pacific right whale: 1 animal, gray whale: 62 animals, fin whale: 43 animals, sei whale: 1 animal, humpback whale: 24 animals, killer whale: 10 animals.
(2) Collection of biopsy samples (number of animals)
North Pacific fight whale: 1 animal, gray whale: 32 animals, fin whale: 12 animals, sei whale: 5 animals, humpback whale: 12 animals.
(3) Whale vocalization recording (number of animals)
We conducted 614 hours of acoustic monitoring at 149 stations and recorded the vocalization sounds of North Pacific right, gray, fin, humpback sperm, and killer whales.
(4) Marine debris (number observed)
We recorded 14 cases of marine debris in the research area.
Figure 1. 2025 IWC-POWER survey area (green), and survey course (blue bold lines).
Photographs from the 2025 IWC-POWER cruise
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| Surface-feeding humpback whale. | A fin whale surfacing to breathe. | |
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| Spouting gray whale. | Collection of skin samples from a gray whale. | |
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Crewman searching for whales. | International researchers and crew. |
Completion of the 2025 IWC/Japan Joint Cetacean Sighting Survey Cruise in the North Pacific - IWC-POWER (PDF file)