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On the evening of March 13, 2020, Michelle Fournet was preparing for lockdown like so many others. Yet while she was packing up her office at Cornell University in Ithaca, New York, she realized that the impending quarantine may be presenting her with a once-in-a-lifetime chance. An expert on marine mammal communication, especially of humpback whales in Alaska’s Glacier Bay National Park, a popular destination for cruise ships, tour boats, and recreational boaters, Fournet saw the sudden shutdown as an opportunity to see how humpbacks vocalize in a sea with less vessel noise. Locked down in New York, she reached out to colleagues in Alaska, where Christine Gabriele was able to sink a hydrophone in the same location where Gabriele had recorded the whales in the summer of 2019. Gabriele monitors humpbacks for the US National Park Service in Glacier Bay.
Fournet spent the winter and spring listening to the hydrophone’s recordings and compared them to the previous year’s. The analysis shows that even in the absence of cruise ships, the humpbacks made about the same number of kinds of calls. But her initial data, which has yet to be published, shows one key change: the humpbacks made a certain kind of call, which she calls a whup, much less often.
In the summer of 2019, about 66 percent of humpback whale calls were whups. In 2020—when traffic was down by 44 percent and median noise levels were three times lower than usual—the frequency of the whales’ whups fell to less than 50 percent.
Fournet also compared her tally of calls to recordings of humpbacks made in 1976 by researcher Roger Payne, who was studying the whales in nearby Frederick Sound. The proportions of whups in that 45-year-old recording, which was made in the absence of boats, Fournet says, closely resembles her recordings made in 2020.
Fournet’s finding is among the early results from studies leveraging the so-called anthropause—a name coined for the sudden slowing or shutdown of human activity around the world because of COVID-19 lockdowns—that hint at the subtler impacts of noise pollution on marine life.
For the most part, researchers don’t know what each kind of humpback whale vocalization actually means. Based on her earlier work, however, Fournet thinks that for the Glacier Bay humpbacks, whups are a kind of contact call. “It’s a way of announcing their presence,” Fournet says. This may help them keep their spacing as they feed on capelin, sand lance, and other fish.
If that interpretation is correct, the prevalence of whups in non-pandemic times suggests that cruise ship noise may be affecting humpbacks’ table manners.
Scientists know that noise pollution can make it more difficult for marine animals to hear each other, find food, and navigate, and can also result in hearing damage. But Fournet says they are just beginning to look at the more subtle impacts, such as how a change in call proportion could affect the quality of interactions.
Paul Spong and Helena Symonds, who run OrcaLab, a whale research station off the east coast of Vancouver Island in British Columbia, where cruise ships pass on their way from Seattle, Washington, to Glacier Bay, saw a less pronounced anthropause, with boat traffic and other noisemakers persisting. But they did get a respite from cruise ships, Spong says, which can drown out everything else for an hour as they pass. With none in the water, he says, “it was just beautiful listening to [the whales].”
Spong and Symonds haven’t linked specific humpback vocalizations to specific meanings in British Columbia. However, Symonds says that OrcaLab is one of several research centers that installed a coordinated network of new hydrophones along the British Columbia coast in 2020. So, with cruise ship activity ramping up again, they will be able to compare their 2020 recordings of ambient noise, industry, and whales to post-pandemic years. “I think any noise in the ocean, especially big noise, is disruptive to behavior,” Spong says.
However, even if researchers can show marked changes in humpback vocalizations in the face of ship noise, linking that data to social impacts is difficult. Jackie Hildering, the cofounder of the Marine Education and Research Society in Port McNeill, British Columbia, explains one reason why: the meanings of calls may vary depending on what the whale is doing, where it is, and critically, who is making it.
“Individuals do different things in different places,” Hildering explains. A broader cultural context, such as whales’ identities, relationships, or migration routes, is necessary to understand any given call—or the implications of changes to those calls triggered by noise pollution.
In the future, Fournet and Gabriele hope to incorporate demographic data collected by Gabriele and the humpback monitoring team in Glacier Bay with the sounds recorded on the hydrophones before and during the pandemic.**
Fournet hopes that as they further quantify these changes, the data will reveal not only how the whales were vocalizing differently during the anthropause in the unique theater of Glacier Bay, but what they were saying.
*Correction: This story was updated to clarify that cruise ships are not the only source of vessel noise in Glacier Bay, and that compared to nearby waters outside of the national park, cruise ship activity in Glacier Bay is actually quite low.
**Correction: This story was updated to clarify that the researchers are comparing humpback whale calls with demographic data, not with specific observations of what the whales were doing at the time they made the call.
***Correction: This story has been updated in a number of places to clarify the partitioning of labor between the researchers.