This article isn't necessarily about "Shinto," but the legend about the fish is one I haven't come across before and anxieties around natural disasters in Japan have a long and understandable history that intersect with folklore (like the namazu).
By Alex Stambaugh and Yoko Wakatsuki, CNN (2/1/2019)
Fears of an incoming natural disaster in Japan are swirling online after sightings of a deep-water fish believed to be a harbinger of earthquakes and tsunamis.
On Friday, two oarfish were discovered after being caught in fishing nets off the northern prefecture of Toyama, bringing the total found this season to seven. Earlier this week, a 3.2 meter (10.5 foot) oarfish washed up on the shore of Toyama Bay, while a 4-meter (13 foot) long oarfish was tangled in a fishing net off the port of Imizu.
The elusive oarfish live between 200 and 1,000 meters (650 to 3,200 feet) deep and are characterized by silvery skin and red fins.
Traditionally known as "Ryugu no tsukai" in Japanese, or the "Messenger from the Sea God's Palace," legend has it that they beach themselves on shores ahead of underwater earthquakes. But scientists dispute such claims.
"There is no scientific evidence at all for the theory that oarfish appear around big quakes. But we cannot 100% deny the possibility," Uozu Aquarium keeper Kazusa Saiba told CNN.
"It could be that global warming might have an impact on the appearance of oarfish or a reason we're just not aware of."
The myth of oarfish as harbinger of destruction gained some traction after the 2011 Fukushima earthquake and subsequent tsunami, which killed more than 20,000 people. At least a dozen oarfish had washed up onto Japan's coastline in the year prior to the disaster, according to Kyodo News.
While he doubted the theory's validity, Saiba said one possible scientific explanation could be that subtle changes in the earth's crust at the bottom of the sea ahead of an earthquake "might cause the current to stir and push creatures at the bottom to the surface."
But Osamu Inamura, director of Uozu Aquarium, had a more scientific theory about the Toyama Bay sighting -- that oarfish are following the movement of their food supply, a kind of a micro shrimp.
"When their shrimp supply rises toward plankton during the daytime, the oarfish may sometimes follow and get caught in fishermen's nets," Inamura said.