It's not just plastic. Noise pollution threatens endangered Cook Inlet Belugas

Published: May. 28, 2019 at 6:53 PM AKDT
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While images of dead whales washing ashore with bellies full plastic have been widely shares across the globe, wildlife biologists say there is a greater and more urgent threat to the wellbeing of the endangered Cook Inlet Beluga.

"There's been a lot of media coverage of late of humpback whales, other whales with their stomachs full of plastic. That's not something we've necessarily seen up here," Verena Gill, wildlife biologist with the National Oceanic and Atmospheric Administration said. "So people think about plastic debris and that's definitely a problem, but people don't think about noise pollution, which is as much as, if not more of a problem."

Toothed whales, which include the estimated 328 remaining Cook Inlet belugas along with orcas, use echolocation to communicate, navigate and track down their food.

The whales emit a series of clicks and can tell what's in their surroundings based on how the sound waves reflect back to them.

"That's particularly important in a place like Cook Inlet where it's extremely hard to see. It's very silty," Gill said.

NOAA records sound from the bottom of Cook Inlet with acoustic monitors. The monitors record around the clock and are retrieved every six months.

An analysis of five years of acoustic monitoring published last week in NOAA's Marine Fisheries Review found that there was not a single day of recordings without human-made noise.

Nine noise sources were identified as commercial ships, dredging, helicopters, jet aircraft (commercial or military non-fighter), fighter jet, propeller aircraft, outboard motor, pile driving, and sub-bottom profilers, a type of underwater remote operated vehicle. Four additional noise sources were not identified.

Underwater noise is currently regulated for activities including pile driving and seismic surveys, but researchers are concerned about the cumulative effect of all noise sources.

"You cannot see in front of your face out there, so that's how they see is through this echolocation. And so if this is being disrupted by some of these sounds out there - the pile driving, the ship noise, the airplane noise - that is going to make it incredibly hard to find food, even if the food is right in front of them," Gill said.

Researchers described the areas between the Port of Alaska and Port MacKenzie as "highly disturbed acoustically due to the convergence of different sources of noise."

Because the area is geographically constrained, researchers say there is considerable potential for creating a barrier that reduces belugas passing through.

The Marine Mammal Commission lists noise as one of three threats of high relative concern for the beluga's recovery plan. The only other threats at the highest level are catastrophic events -- including natural disasters and spills -- and cumulative effects of multiple stressors.

Gill says while NOAA works with industry leaders to mitigate underwater noise, there is a role individuals play.

"I think on a personal level someone might say, 'Well what can we do? It is what it is,' " Gill said, suggesting Alaska residents consider their purchasing habits, since most items come to the state through the Port of Alaska.

"I thought long and hard about it," Gill continued, "and I honestly think it comes down to consumerism."

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