Walrus Survey: UAS Noise Research on Marine Mammals

Three management agencies within the Department of the Interior (DOI) are interested in estimating the number of Pacific walruses in the U.S. waters of the eastern Chukchi Sea.  The Bureau of Ocean Energy Management (BOEM) has leased substantial sectors of the northeastern Chukchi Sea for oil and gas development, and these leases are near the offshore foraging areas used by Pacific walruses. The U.S. Fish and Wildlife Service (USFWS) has an interest in knowing the number of walruses in the eastern Chukchi Sea due to mandates in the Marine Mammals Protection Act (MMPA) and the Endangered Species Act (ESA).  Under the MMPA, USFWS has authority to manage the Pacific walrus population, and USFWS is in the process of evaluating the Pacific walrus as threatened under the ESA, with a final ESA decision pending in 2017.  For these reasons, USGS seeks to estimate the number of Pacific walruses in the eastern Chukchi Sea. 

ptarmigan for walrus survey

In recent years, beginning in 2007, in the absence of sea-ice, Pacific walruses have gathered in very large numbers on the U.S. shores of the northeastern Chukchi Sea.  When walruses gather in larger numbers on the coast, these walruses may be efficiently counted by aerial survey.  The use of a UAS may significantly increase our ability to obtain quality survey data with a much reduced chance of disturbing the population.

To explore the potential of this technology, the U.S. Geological Survey (USGS) partnered with the Alaska Center for UAS Integration (ACUASI) for the permitting, operation, and collection of aerial survey data of walruses with a UAS.  For the noise research, two distinct missions were defined.

The first mission occurred in July 2015 offshore in the Chukchi Sea with walruses resting on sea-ice. The mission involved flying multiple rotary UAS configurations at various altitudes, while hovering, ascending, descending, and photographing walruses.  To capture the data, the Norseman II ship traveled from south of the Bering Strait and followed the pack ice north for approximately two weeks looking for groups of walrus. The vessel typically ranges from the US/Russian border to a few miles from shore.  The first UAS mission was successfully flown with data gathered and provided to USGS.  But, we encountered difficulty with the second mission which was scheduled to occur near Point Lay.  All of the Walrus migrated too close to the Point Lay Airport within a UAS restricted area and remained there; this caused the mission to be delayed.

walrus survey boat

A second mission is currently being planned.  Prior to each survey flight, the selected rotary UAS will fly over the periphery of the herd so that USGS may observe potential response behaviors of the herd to the UAS overflights.  The combination of missions will provide the noise research necessary to determine if this is an optimal method of data collection under certain circumstances.