According to lore, the fish rise to the surface and beach themselves ahead of an impending earthquake. That ties in with scientific theories that bottom-dwelling fish may very well be susceptible to movements in seismic fault lines and act in uncharacteristic ways before an earthquake.

Hiroyuki Motomura, a professor of ichthyology at Kagoshima University, has a more mundane explanation for the recent discovery of oarfish off Toyama Prefecture.

"I have around 20 specimens of this fish in my collection so it's not a very rare species, but I believe these fish tend to rise to the surface when their physical condition is poor, rising on water currents, which is why they are so often dead when they are found," he said.

"The link to reports of seismic activity goes back many, many years, but there is no scientific evidence of a connection so I don't think people need to worry."

Oarfish - characterised by long silver bodies and red fins - usually inhabit deep waters and the fish are rarely seen from the surface, although legend has it that when oarfish rise to shallow waters, disaster is near. via Strait Times

Nevertheless, the oarfish's reputation as an indicator of imminent doom was enhanced after at least 10 oarfish were washed up along Japan's northern coastline in 2010. In March 2011, a magnitude-9 earthquake struck off northeast Japan, triggering a massive tsunami that killed nearly 19,000 people and destroyed the Fukushima nuclear plant.

With that anniversary looming, people on social media became jittery about the omens.

A message on Twitter claimed: "This is no doubt evidence of a precursor to an earthquake. And if it is in the Nankai Trough, it might be a huge quake."

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