The researchers presented their findings at the Society for Integrative and Comparative Biology meeting on Tuesday, marking another step in understanding how animals can detect Earth's magnetic field or be influenced by other celestial bodies.
"It's a fascinating finding," Kenneth Lohmann, a biologist at the University of North Carolina at Chapel Hill, told Live Science in an email. "There have been several previous reports linking magnetic storms to whale strandings, but this is a particularly well-done and convincing analysis," said Lohmann, who was not involved in the study.
Jesse Granger, a conservation biophysicist at Duke University in North Carolina and the lead study author, said they believe that migratory whales, such as grey whales, are likely to use magnetoreception – the perception of magnetic fields – to navigate throughout the ocean – thus the radio waves from solar storms can disrupt it.
Grey whales usually swim from March to June from the coast of Baja California, Mexico, to the Bering and Chukchi seas, looking for food, starting their journey back in November. However, during their journey, some of the whales occasionally get lost, and the authors of the study suggested that the possible reason is if something was disrupting Earth's magnetic field or the whale's ability to detect it.
Granger and her colleagues reviewed grey whale stranding data from the US West Coast between 1985 and 2018 and found a correlation – the whales were stranding far more often when there were a high number of sunspots. However, since most of the electromagnetic radiation from the Sun is blocked or scattered by Earth's atmosphere, it is still a mystery how exactly it affects whales’ navigational abilities.
“There's a huge chunk in the radio frequency (RF) wave range that does make it all the way to the Earth," Granger said. "And, it's been shown in several species that RF noise can disrupt a magnetic orientation ability."
The researchers found there was a 4.8-fold increase in the likelihood that a whale would be lost on days when there was high RF noise, suggesting that solar storms can affect whales' magnetic receptor. Yet the very existence of this receptor has yet to be proven. All we know, Granger said, is that "whales are stranding a lot more often when the sun is doing crazy stuff.
Lohmann added that magnetic storms are also known to cause other issues for animals unrelated to navigation, “so, more work will be needed to determine whether the storms are affecting whale navigation or having some other effect.” The team now aims to determine if this phenomenon is true for other migratory species and in other parts of the world – for example, where the magnetic field may not be as easily detected.