NATIONAL MARINE MAMMAL LABORATORY (NMML) (cont.)

CETACEAN ASSESSMENT AND ECOLOGY PROGRAM:

Bowhead Whale Data

In June/July 2004, the International Whaling Commission (IWC) will be conducting an Intensive Assessment of the western Arctic stock of bowhead whales (Balaena mysticetus). As a part of the assessment, all relevant data was prepared for any reanalyses that might be required in the intervening months.

Between 1976 and 1998, the NMML and LGL (environmental research associates) collected aerial photographs of bowheads during the spring migration near Barrow, Alaska, as well as during the summer in the Beaufort Sea. Data from these photographs have been combined into a uniform database. Information on each photo includes time and location, image quality, amount of marks on whales, and lengths of whales. NMML also provided data from aerial transects flown in support of the ice-based censuses conducted in the Barrow area. (These censuses were under NMML direction until 1982 but are now done by the North Slope Borough). Most of these data files were compiled by Dr. Judy Zeh at the University of Washington prior to delivery to the IWC. Data from other laboratories include acoustic locations of whales during census periods, harvest records, corpora rates, pregnancy information, aging indicators relative to baleen growth and lens racemization, and genetics.

By Dave Rugh.


Joint Russia-Canada-US Project to Tag Belugas off the Chukotka Peninsula

In November and early December 2003, Rod Hobbs (NMML), Greg O’Corry-Crowe (Southwest Fisheries Science Center (SWFSC)) and a Russian colleague, Dennis Litovka (ChukoTINRO), traveled to Lavrentia Bay on the Chukotka Peninsula in far eastern Russia. The trip was the first field season of a 3-year joint Russia-Canada-U.S. project to collect genetic samples from and attach satellite transmitters to beluga whales that spend a few weeks each fall in Lavrentia Bay. The genetic samples will provide information on the stock identity of the whales and may indicate that these whales spend time in U.S. or Canadian waters. The biopsy samples will be collected either directly while handling the belugas to attach transmitters or remotely by using a crossbow and biopsy dart. The satellite transmitters will collect dive information and transmit these data to an ARGOS receiver on a satellite. The location of the whales will then be calculated from the location of the satellite and the Doppler shift in the radio signal. The location and dive data from the satellite tags will provide information on the movements and behavior of the belugas as they (presumably) overwinter in the Bering Sea and, possibly, during their spring and early summer migration.

The field team spent a productive field season scouting capture locations and developing contacts with local Chukchi, Inuit, and Russian marine mammal hunters to get biopsy samples from harvested belugas. However, the belugas did not arrive at Lavrentia Bay during the field season. Local knowledge indicates that the belugas typically move south into the Bering Sea with the sea ice, and sea-ice formation was unusually late this fall. Although Lavrentia Bay had frozen over by the end of the field season, sea ice had not formed offshore from the bay. However, a local hunter sighted belugas near the field location 4 days after the field team departed, and he collected biopsy samples from whales harvested in the area. These samples will be sent to the genetics lab at the SWFSC for analysis.

By Rod Hobbs.


Workshop on Odontocete Capture and Handling Techniques

A workshop, entitled “Capture and Handling Techniques for Small Odontocetes During Tagging, Health Assessment, and Sample Collection,” was convened in mid-December at the 15th Biennial Conference on the Biology of Marine Mammals, in Greensboro, North Carolina, by Rod Hobbs (NMML), Stephanie Norman (NMFS Northwest Region), Jonas Teilmann (Denmark), Tony Martin (UK), and Brad Hanson (NWFSC), with funding from NMML. The workshop provided a forum for the exchange of ideas between researchers, veterinarians, and other interested parties on handling and attachment practices during tagging and other capture activities. The capture-release of odontocetes for tag deployment, as well as for clinical assessments and tissue collection, has become an important component of studies of behavior, range, habitat use, and the health and reproductive status of free-ranging animals. The workshop emphasized techniques and issues related to animal and human safety that are common to studies of several species.

The workshop opened with a series of oral presentations along with poster sessions during the breaks. This was then followed by a group discussion which focused on specific issues raised during the talks. The workshop was attended by more than 60 people, ranging from students to scientists with many years of experience in handling cetaceans. The talks included specific examples of capture and handling techniques for a variety of species and circumstances, as well as issues concerning the successful handling and health and well being of the animals and their handlers, such as monitoring animals during handling, tag-release mechanisms, and zoonotic diseases.

By Rod Hobbs.


Abundance of Cook Inlet Belugas

NMML scientists have completed an abundance estimate for the Cook Inlet beluga population from observer counts and video data collected during an aerial survey of Cook Inlet in early June 2003. During the survey, the complete coastline of the inlet and several transects of offshore waters were surveyed (see July-September 2003 Quarterly Report for additional details). Aerial video of beluga groups was analyzed and compared to observer counts to estimate group sizes, which were summed to estimate the population abundance. We estimated that there are 357 whales in the population. This estimate has a CV of 10.7%, yielding a 95% confidence interval of between 289 and 440 belugas and an N_min, for management purposes, of 326 belugas (Fig. 1 above). This abundance estimate falls within the range of estimates over the previous 5 years, which suggests that there is no significant increasing or decreasing trend.

By Rod Hobbs.

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AFSC Quarterly
Research Reports
Oct-Nov-Dec 2003