NATIONAL MARINE MAMMAL LABORATORY (NMML) (cont.)

Cetacean Assessment and Ecology Program

North Pacific Right Whale Satellite Tagging Project

In August 2004, the Cetacean Assessment and Ecology Program (CAEP) at the National Marine Mammal Laboratory initiated a North Pacific right whale (Eubalaena japonica) tagging project. This is a collaborative study with the whale-tagging group at the Greenland Institute for Natural Resources in Copenhagen, Denmark. Three main questions are being addressed by this study:

1. Where do North Pacific right whales go in winter?
2. What migratory route do they take to get to their wintering grounds?
3. Do right whales found in the “right whale box” in the southeast Bering Sea in summer also use other feeding areas in Alaska?

The project should also provide information about specific habitat use in the Bering Sea, with the potential for investigating the oceanographic conditions of those areas.

The right whale satellite-tagging project was just one element of a 40-day multispecies cetacean survey called the Alaska Cetacean Ecosystem (ACE) survey. The ACE survey included four separate legs: 1) a survey focused on killer whales (Orcinus orca) and humpback whales in the eastern Aleutian Islands; 2) a survey focused on killer whales in the central Aleutian Islands; 3) a multispecies cetacean survey from Dutch Harbor along the Bering Sea shelf break to the Pribilof Islands; and 4) a right whale survey in the southeast Bering Sea. The killer whale studies are part of ongoing killer whale research conducted by CAEP in western Alaska. The humpback whale studies are one component of the international North Pacific-wide SPLASH humpback whale project.

The goal of the right whale survey was to find North Pacific right whales, deploy satellite tags on them, and collect photo-identification data and biopsy samples. The charter vessel Alaskan Enterprise was used to conduct a survey from 6 to 17 August 2004 in the southeast Bering Sea. Nine scientists participated in the survey, including a sighting team of six scientists, two acoustic technicians, and a technician to deploy the satellite tags. The sighting survey team used 25-power and 7-power binoculars to visually scan for whales from one half-hour after sunrise to approximately one half-hour before sunset. The acoustic researchers deployed directional sonobuoys (underwater listening devices) to listen for right whale calls. When calls were heard, the researchers could calculate a bearing (direction) towards the calls to lead the ship to the location of the whales.

At the beginning of the right whale survey, the Alaskan Enterprise was used to conduct killer whale studies along the north side of Unimak Island. Three groups of mammal-eating killer whales (“transients”) were photographed near a Steller sea lion colony on Sea Lion Rocks near Amak Island. Then the ship headed north for the “right whale box” (where nearly all previous sightings have occurred in the last decade). On 10 August, the acoustic researchers deployed a sonobuoy at 1200h and heard distant right whale calls. They calculated a bearing towards the calls and the ship headed in that direction. At around 1900h, about 57 nmi from where the calls were first heard, two right whales were seen near the horizon. The ship approached the whales for some initial photographs and then launched a 22-ft rigid-hulled inflatable skiff to deploy satellite tags on the whales. The satellite-tagging technician placed a tag on the first whale around 2030h, and a tag was placed on the second whale around 2130h. Both whales were fairly large; the larger of the two was likely an adult and the second, slightly smaller whale was likely a small adult or subadult. No additional right whales were found during the survey; high winds that began on 12 August prevented further survey effort in the “right whale box.”

One of the tagged whales was successfully tracked from 10 August through 19 September. This whale spent over 3 weeks in an area, approximately half-way between Unimak Island and the Pribilof Islands, that was south of the “right whale box.” In September, location information for this whale was given to scientists aboard the NOAA ship McArthur II, who were conducting a SPLASH-project humpback whale survey in the Gulf of Alaska and Bering Sea. These scientists located right whales and were able to photograph 25 individual whales and biopsy sample 20 whales, more than doubling the known number of individuals in the North Pacific. In terms of samples, this was by far the most successful summer of right whale research conducted to date in the Bering Sea.

By Paul Wade


Cetacean Surveys in Southeast Alaska

NMML has conducted long-term studies on cetaceans in Southeast Alaska since 1989. The primary purpose of these studies is to collect information on the distribution, abundance and trends, and stock structure of cetaceans.

In 2004, two cruises were conducted aboard the John N Cobb. From 1 to 12 July, the main focus was to collect photographs and biopsy samples from humpback whales. This study was part of the larger SPLASH North Pacific humpback whale research effort (see the SPLASH Surveys report in the beginning of this program section). The waters throughout Sumner Strait, Clarence Strait, and the west coast of Prince of Wales Island were surveyed. During the July survey, 67 hours of SPLASH search effort were conducted, and 26 hours were spent with humpback whales during 26 encounters over a 9-day period. Based on this research effort, 68 individual whales were uniquely identified and 7 whales were biopsy sampled.

During the 11-24 5eptember cruise, the main emphasis was to collect photographs of killer whales. However, images of humpback whales were collected on an opportunistic basis. Inland waterways throughout Southeast Alaska from Juneau to Ketchikan were surveyed, including Icy Strait, Chatham Strait, Sumner Strait, Clarence Strait, Frederick Sound, and Stephens Passage. During nine encounters with humpback whales, photographs of 57 unique individual whales were collected. In September, humpback whales were found in large concentrations throughout Frederick Sound unlike the July survey in southern waters, when small groups of humpback whales were scattered throughout the survey area. Images of each individual whale photographed during the 2004 season will be compared to photographic catalogues of North Pacific humpback whales to determine if matches occur.

During the 2004 season, there were 12 encounters with killer whales, including whales from all three ecotypes (resident, transient, and offshore). Images collected over the last 3 years are being used to update NMML’s photographic catalogue of Southeast Alaskan killer whales. Work is under way to create a digital catalogue that will be readily available to both researchers and to the various communities throughout Southeast Alaska.

By Marilyn E. Dahlheim

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AFSC Quarterly Research Reports July-Sept 2004