Contact: Katy Human, 303-497-4747 | May 10, 2012
Since the 1970s, the population of Steller sea lions has declined dramatically in the western Aleutians Islands of Alaska, and the western stock is listed as endangered under the Endangered Species Act. Keeping tabs on Steller sea lion populations is the responsibility of NOAA's National Marine Mammal Laboratory (NMML). NOAA Marine mammal biologists and their colleagues are experimenting with a potentially powerful new survey tool: unmanned aircraft systems (UAS).
NMML researchers, who work within NOAA's Alaska Fisheries Science Center, routinely fly traditional manned aircraft over the Steller sea lions' Alaska home. That territory stretches from southeast Alaska along the Alaska Peninsula and west to Attu, the westernmost Aleutian island. On March 4, the Geophysical Institute at the University of Alaska Fairbanks worked with NMML's population survey team to try something new – a quieter and possibly safer approach.
Eleven scientists, engineers, pilots, and NOAA Corps officers boarded the 108-ft research vessel Norseman in Adak, Alaska. They embarked on a three-week research mission to study the winter diet of Steller sea lions, and to test the feasibility of using unmanned aircraft systems to survey Steller sea lions. The sea-going mission was a collaborative effort of NMML and the University of Alaska Fairbanks, both of which received grant support from the North Pacific Research Board. The university team focused on the potential of using unmanned aircraft to augment surveys, and NMML scientists studied what the animals eat in winter. During the March cruise, the team visited 54 sites that had a total of almost 3,000 Steller sea lions.
During this cruise, the University of Alaska Fairbanks researchers tested two types of unmanned aircraft – the Aeryon Scout and the AreoVironment Puma AE. The Scout is a small, battery-powered, four-bladed helicopter-like aircraft with an on-board sophisticated camera and video system. A pilot on the ground or in a boat directs the Scout by remote control. The Scout can fly for 25 minutes at a time, and during the March cruise, it made 30 flights on 10 days over 14 sea lion sites. The Scout took thousands of photos of sea lions and was able to take enough overlapping photos at one summer breeding location to produce a three-dimensional map.
The Puma AE is a fixed wing battery-powered aircraft with a 10-ft wingspan, equipped with real-time video plus infrared and visual still photo capability. The Puma can fly for up to two hours, and during the March cruise, it made nine flights in seven days over nine sea lion sites.
Neither unmanned aircraft requires an airfield, and either can be hand-launched from any location on land or at sea from a boat. They are lightweight and land with minimal damage to the aircraft. The fully waterproof Puma landed multiple times in the Bering Sea, sustaining no damage.
Unmanned aircraft can fly lower and slower than manned aircraft and are much quieter, enabling researchers to observe animals at relatively close range with minimal disturbance. During the March flights, the aircraft generally flew at altitudes below 525 feet when over land and often below 300 feet when approaching haulout sites, where sea lions routinely rest and socialize on land. Because unmanned systems do not require an airfield, they can be operated in areas that could pose considerable danger to manned survey flights, such as near cliffs and over long stretches of open water.
NOAA Steller sea lion researchers have reviewed the imagery from the unmanned aircraft and are confident that the instruments on both the Scout and Puma are capable of documenting the presence or absence of Steller sea lions. Unmanned aircraft also show potential for some new, unexpected applications, including the ability to identify specific individuals and three-dimensional habitat mapping.
NOAA's UAS Program is encouraged by the results of this experiment, and looks forward to continuing to investigate how unmanned aircraft can be used to support NOAA's mission.
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