Long, slender and snake-like, the giant oarfish is rarely found less than 200m 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.
Which is why 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 visible signs of injury or disease, leading to speculation that they were affected by some deep underwater disturbance.
Dr 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," 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 before an earthquake there is a release of large quantities of carbon monoxide gas, which could also affect oarfish and other deep-sea creatures, Grant said. "The geophysical processes behind these kinds of sighting can happen before an earthquake."
A 4.3m oarfish was found on a beach near the city of Oceanside last weekend, while a 5.5m specimen was washed up on Santa Catalina Island a few days earlier. Tests on the fish failed to find any obvious reason for the stranding, though 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 and marine biologists remain unconvinced.
Milton Love, a research biologist at the Marine Science Institute at UC Santa Barbara, said, "If the oarfish popped up an hour before an earthquakes, I could speculate that they were affected by a sound emitted before the quake, or by some toxic gases. But if the event happened a week or more before, I'm not so sure ... these animals strand themselves all over the world."
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 an 800km radius. Love said since records began there have been no more than 10 or 12 total strandings of oarfish in Southern California, though they have been known to beach themselves in pairs.
"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," Grant said.
The oarfish myth is one of several surrounding unusual animal behaviour or observations before earthquakes. Elephants were reportedly seen running for the hills of Thailand and Sri Lanka before the Boxing Day tsunami of 2004, and in 1975 officials in Haicheng, China, ordered an evacuation based in part on peculiar animal behaviour. A 7.3-magnitude earthquake struck the city the following day. Grant has shown in earlier research that there was no link between reports of mass migrations of young frogs and earthquakes.