A new collaborative study documenting the complex vocal repertoire of Cook Inlet beluga whales has quantified how ship noise may be masking specific beluga calls crucial to the safety and wellbeing of these endangered whales.
Beluga whales use acoustics to find prey, navigate their environment, avoid predators and maintain group cohesion, according to authors of the study published on Nov. 30 in the Journal of the Acoustical Society of America.
Beluga whales are highly social and vocal marine mammals, according to study lead author Arial Brewer, who’s a NOAA Fisheries affiliate at the Alaska Fisheries Science Center and Ph.D. student at the University of Washington.
“The core critical habitat for these whales is a very noisy area,” she explained. “Commercial shipping, an international airport, military operations, and gas and oil exploration are all concentrated there.”
The study is the first to document the complex vocal repertoire of the endangered beluga whales. It is also the first to quantify how ship noise may be masking specific beluga calls in this region. Findings were a collaborative effort between NOAA Fisheries Alaska Fisheries Science Center, the University of Washington and Alaska Department of Fish and Game.
“A fundamental knowledge gap for the Cook Inlet beluga population is how they communicate important information. The first step is to describe their vocal repertoire,” Brewer stated. “With that information we can begin to understand if their communication is impacted by human-caused noise.”
There are 21 recognized populations of belugas worldwide, including five distinct populations in Alaska. The geographically and genetically isolated Cook Inlet beluga population is the smallest, with an estimated 331 individual whales.
Cook Inlet beluga whales live exclusively in their namesake waters alongside Anchorage, Alaska’s largest city and busiest port.
The Cook Inlet beluga whale population was listed as endangered under the Endangered Species Act in 2008. That led to the designation of critical habitat in 2011. However, the population has remained low.
A 2016 recovery plan ranked human-caused noise among the three highest level threats of concern.