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London - Long, slender and snake-like, the giant oarfish is rarely found fewer than 200 metres from the surface of the ocean. Yet in the year leading up to the devastating 2011 Tohoku earthquake and tsunami, between 10 and 20 of the deep-sea creatures washed up dead along the coast of Japan.
Ancient Japanese fishermen's lore suggests the oarfish - known as the “messenger from the sea god's palace” - rises to the surface to warn of impending earthquakes.
So people in southern California are a little nervous at the news that this month at least two oarfish have been sighted on their beaches without any sign of injury or disease, leading to speculation that they were affected by some deep underwater disturbance.
Rachel Grant, a lecturer in animal biology at Anglia Ruskin University in Cambridge, said there might be some truth to the Japanese legend, and she has begun a study to test the idea. “It's theoretically possible, because when an earthquake occurs there can be a build-up of pressure in the rocks which can lead to electrostatic charges that cause electrically-charged ions to be released into the water,” Dr Grant said. “This can lead to the formation of hydrogen peroxide, which is a toxic compound. The charged ions can also oxidise organic matter which could either kill the fish or force them to leave the deep ocean and rise to the surface.”
Another possibility is that prior to an earthquake there is a release of large quantities of carbon monoxide gas. “The geophysical processes behind these kinds of sighting can happen before an earthquake. I will be watching California closely over the next couple of weeks,” she added.
A 4.5m oarfish was found on a beach near the city of Oceanside last Friday, while an even larger specimen was washed up on Santa Catalina Island a few days earlier. On the day following the second beaching, a 6.4-magnitude earthquake was recorded in the Gulf of California.
Californians frequently discuss the possibility of “The Big One”, a devastating earthquake to match some of the state's historical seismic catastrophes. But local geologists remain unconvinced by the omen. “I don't discredit or disrespect the Japanese theory at all,” Pat Abbott, a seismologist at San Diego State University told ABC News.
“But there's a big difference between suggesting something like that and proving it. What did an animal sense that maybe we didn't that told them about a coming event?”
Dr Grant said she has built up a database of several hundred oarfish sightings over the past two and a half years, and will now see if there are links between the sightings and any earthquakes reported by the US Geological Survey within a 500-mile radius. There have been at least four reported sightings in southern California since 2010.
“We do know that there's not an earthquake after every oarfish sighting, but we are going to see if there is an increased probability of oarfish being seen prior to an earthquake,” Dr Grant said. “It may be due to seismic activity or it may be due to other factors unconnected with earthquakes, such as infrasound caused by underwater activities, such as military submarines, or pollution.” - The Independent