A Southern Resident killer whale just beneath the surface of the water
Photo courtesy of Sara Shimazu.

In 2020, NOAA Fisheries—the government agency responsible for marine mammal protection—authorized the U.S. Navy’s request for 7 more years of training/testing in the Pacific Northwest.  An assessment concluded potential harm to 28 species of marine mammal—including the endangered Southern Resident killer whales—from use of sonar and by in-water detonations, but that aircraft were not likely to adversely affect endangered species, or their habitat.

Yet a team of scientists analyzing noise—both above and below the water—from aircraft operating out of the Naval Air Station on Whidbey Island, found that impacts on the Southern Residents, “have been unstudied, underestimated, or otherwise dismissed,” both by the U.S. Navy, and NOAA Fisheries.

What was the research?

The scientists sought to answer two questions: Can noise from Growler aircraft impact both land and sea habitats? How does it compare to previous studies showing thresholds at which people and wildlife are impacted?

Over the last decade, the U.S. Navy has increased operations out of its base on Whidbey, the largest Salish Sea island; including a fleet upgrade to a more powerful aircraft, the Boeing EA-18G Growler. In 2019, the number of Growlers at the base rose from 82 to 118 aircraft, an increase of 44%. Growler training primarily involves “touch-and-go” aircraft carrier landing procedures, but also air-to-air combat.

With increasing flight frequency, and amplified noise levels, island residents began to express concern for their own health, as well as for local wildlife. The scientists noted that, “the implications of a concurrent change to more powerful aircraft and increased operations for noise pollution have not been measured, leaving knowledge gaps in the ability to assess vulnerability of both people and wildlife, including Endangered, Threatened or sensitive species.”

They recorded noise levels under known Growler flight paths: with in-air recordings from a county beach captured over two typical military training days in Sept 2019, while an underwater microphone (hydrophone) recorded for 28 days.

An EA-18G Growler aircraft rolls down a runway.
Photo courtesy of Mass Communication Specialist 1st Class Bruce McVicar PD-USGOV-MILITARY-NAVY. Creative Commons.

A US Navy EA-18G Growler lands at NAS Whidbey Island.

What conclusions did the government reach?

A 2015 agreement between the U.S. Navy and NOAA Fisheries assumes that aircraft flying above 1,000 feet will not impact marine mammals. However the scientists noted that existing models show that, “underwater noise for aircraft at altitudes of 1,000-10,000 feet exceeds known thresholds for behavioral reactions and adverse impacts on marine mammals, including the Southern Resident killer whales.”

Consequently, the Navy’s Environmental Assessment only considered aircraft flying below 1,000 feet. They assumed that only orcas at the surface—and directly below aircraft—might be impacted by noise. However, they also surmised that vessel noise would “most likely drown out or lessen the sounds of aircraft overflights.”  Yet, the scientists’ research found that underwater Growler noise levels, “are likely to exceed those associated with a range of typical vessel noise.”

Finally, the Navy and NOAA Fisheries concluded that aircraft noise would have no effect on foraging areas in the Salish Sea, crucial to the Southern Residents’ survival—known under the Endangered Species Act as “critical habitat.” However, Naval Air Station Whidbey lies within 112 square miles around 18 military sites in the Salish Sea that are excluded from critical habitat protection. Hence, no impact!

Likely impacts on endangered orcas

This community lives in a world of sound. As highly social mammals, in tight-knit family groups, they’re highly communicative (chatty), staying connected with unique dialects shared by pods. The scientists found that underwater noise pollution from Growlers would force them to increase the volume of their calls and whistles. Critically, it would also impact their reliance on sound to hunt prey, as echolocation—using sound waves— helps them locate, and identify salmon.

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The scientists noted that the Navy and NOAA Fisheries both focused on physical impacts such as hearing damage, or changes in foraging or mating behavior. In fact the scientists’ research found that noise pollution from Growlers was above levels known to cause not just behavior change, but also “avoidance” in killer whales— that is forcing them to leave the area. Yet Whidbey lies within Puget Sound, one of the primary foraging grounds for chum and Coho in fall and winter when their preferred prey—Chinook salmon—is less seasonally available. New research by NOAA Fisheries found that foraging females are disturbed by vessels—presumably noise-related—so why would this not equally apply to aircraft noise?

Finally, the scientists noted that the Navy and NOAA fisheries failed to take into account the cumulative effects of noise pollution on these orcas, as well as the impact to the habitat itself as a less hospitable place to be, “nor that noise may be added to other stressors,” such as other pollution sources, and lack of prey.

These endangered killer whales already face three key threats in the Salish Sea; lack of prey, vessel noise, and contaminants. It seems NOAA Fisheries needs to add military aircraft noise pollution to this list, and then take some action.

This work is made possible in part by a grant from
Rose Foundation