This week, a team of researchers from the U.S. and Russia will jointly kick-off the largest survey effort ever to estimate how many ice-associated seals live in the Bering Sea region.
This large scale, springtime aerial survey will begin this week from Nome. Scientists will use advanced imaging systems and modern statistical techniques to provide the first comprehensive estimates of abundance for the four species of ice-associated seals found in the Bering Sea: ribbon seals, spotted seals, bearded seals and ringed seals. Survey flights will also originate from Bethel, Dillingham, and St. Paul. Each flight will typically last between five and seven hours.
Aerial surveys are the best way to study ice-associated seals in their natural environment while covering large areas in a relatively short amount of time. Spring is the best time to survey because the seals concentrate within the Bering Sea ice pack and spend more time on the ice (where they can be seen and counted) while they have pups, breed and molt.
In the U.S. surveys, two types of aircraft will be used: a NOAA-owned and operated Dehavilland Twin Otter aircraft and a chartered long-range Aero-Commander 690.
Because the aircraft will be flying at an altitude of 1000 feet, too high for the human eye to identify species, high-resolution digital cameras will capture images to be analyzed back in the lab for species identification. Thermal sensors will be used in tandem with the digital cameras to pinpoint the seals, thus reducing the number of images that will need analyzing.
“The most novel thing about the survey is the pairing of two devices that have already been used to survey other marine mammals,” said Peter Boveng, one of the principal investigators of the survey, along with Michael Cameron and Erin Moreland. “Thermal or infrared cameras are good at detecting seals on ice, which are very warm relative to their surroundings, but not good at revealing the species of seals. High-resolution digital photos are good for species identification, but very labor intensive for detecting and counting seals. Putting the two together creates a more efficient system in which the thermal camera finds the seals and the photo camera allows us to identify the seal species.”
The planned survey will include nearly 19,000 nautical miles of track lines over U.S. waters and 11,000 nautical miles over Russian waters, and will last into May. Another spring survey is planned for 2013.
Springtime in the Bering Sea is important not only for seals, but for many other species and the Alaska coastal communities that depend upon them. The seal survey team will be communicating regularly with Alaska Native villages to ensure that the surveys do not conflict with subsistence hunting activities, particularly bowhead whaling around the communities on St. Lawrence Island and in the Bering Strait.
The results of this study will contribute to the scientific understanding of these unique marine mammals and will be used to identify, evaluate and resolve conservation concerns as required by the Marine Mammal Protection Act. The results will also help to assess the risk posed by loss of sea-ice habitat that may occur due to ongoing and anticipated warming of the Arctic climate, a key concern addressed in status reviews that NOAA has conducted on all four species under the Endangered Species Act.
Studying seals in the Bering Sea and Arctic waters pose many challenges that limit the ability for scientists to learn about these special animals. The Bering Sea’s remote location, along with the cold and unpredictable weather, limits scientists’ ability to study these animals in their natural habitat. Figuring out how to efficiently and safely survey the region for seals has been a focus for scientists at the NOAA Alaska Fisheries Science Center and a multi-agency team of Russian collaborators for several years.
Updates from the surveys will be available on this website after survey completion.
For more information go to: http://www.afsc.noaa.gov/nmml/polar/
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