Sunspots and Stranded Whales: A Bizarre Correlation

Then came the email about whales.

Sönke Johnsen, a biologist at Duke University, told Walkowicz that his team had stumbled upon a bizarre correlation: When the surface of the sun was pocked with dark sunspots, an indicator of solar storms, gray whales and other cetacean species seemed more likely to strand themselves on beaches. The team just needed an astronomer’s help wrangling the data.

“This was like a dream request,” Walkowicz said. “And I finally got to do something in marine biology, even though I didn’t study it.”

With that assistance, there is some evidence of this peculiar correlation, the researchers said in a paper published Monday in Current Biology.

“The study convinced me there is a relationship between solar activity and whale strandings,” said Kenneth Lohmann, a biologist at the University of North Carolina who did not participate in the research.

This coincidence across 93 million miles of space is more plausible than it might seem. Sunspots are a harbinger of heightened solar weather, marking times when the tangled plasma of the sun’s atmosphere coughs out more photons and charged particles than usual. These disturbances sail outward and smash into our planet’s magnetic field, creating colorful light shows like the aurora borealis and sometimes disrupting communications.

Biologists have already demonstrated that many animals can navigate by somehow sensing Earth’s magnetic field lines. Gray whales, which migrate over 10,000 miles a year through a featureless expanse of blue, might be relying on a similar hidden sense. But unlike a migrating bird, a whale is not easily placed in a magnetized box for controlled experiments.

Instead, Jesse Granger, a Duke University graduate student, looked at whale strandings, which previous studies had suggested seemed to track with sunspot activity. She narrowed a list of gray whale strandings kept by the National Oceanic and Atmospheric Administration, to highlight the percentage of whales that were stranded alive, as well as whales that were released back to sea and seemed to recover. In theory, those cases were examples of healthy whales that had merely taken a wrong turn.

Sunspot activity waxes and wanes, oscillating over an 11-year period. These strandings followed the same pattern. “They showed the exact same cycle as the sunspots,” Granger said.

Other researchers expressed concerns about the team’s focus on lost whales. Their method included cases that “were almost certainly not” live strandings, said John Calambokidis, a biologist at the nonprofit Cascadia Research who works with NOAA and helped gather the data the team used.

He also said that the correlation might come from a major stranding episode from 1999 to 2000 involving starving whales that coincided with a high period of solar activity.

Granger noted that the research won’t help stop whale strandings. Last year, an unusually high number of gray whales — 123 — washed up dead in the United States. Many were emaciated, unlike the examples in the current study. Investigations are ongoing, but naval sonar, disease and other factors can cause gray whale strandings.

“I’m really trying to make sure that I don’t get someone who hears this story and is like, ‘Oh, I can start blasting sonar wherever I want, because it’s only the sunspots,’” Granger said.

Instead, she hopes to unlock the secrets of magnetic navigation. Aside from sunspot counts, the team also compared strandings with two other markers that also accompany solar squalls. One measure, of how much Earth’s magnetic field was distorted on a given day as it was buffeted by particles from the sun, didn’t seem to matter. But whales appeared to be most sensitive to solar radio frequency noise that intensified during solar storms.

That correlation, if confirmed, suggests that the radio noise is jamming the gray whales’ hypothesized magnetic sensors. Alternatively, Lohmann said, solar activity might also be affecting some other part of whale physiology.

The team now plans to study other whale species. Their findings might suggest new strategies for magnetic sensing experiments on other animals, Granger said:

“You need to be thinking about what the sun is doing, because it is probably interfering with the animals.”

This article originally appeared in The New York Times .