Episode 167 – Giant Oarfish: Seismic Sensitivity?

“…and today we’re talking about the longest boy in the ocean. But more on that later.”

Earthquakes are some of the most destructive events on this planet, snuffing out lives by the thousands and destroying entire cities. The worst part is, we can’t really predict them in advance-or can we? The elusive oarfish is often considered an incredibly long harbinger of earthquakes, and some people see sightings of them as a sign of impending disaster. Let’s find out just how much truth there is to this here in Life, Death, and Taxonomy.

Description of the Oarfish

  • The oarfish is a long slender bony fish with a body shaped like a flat tube. In other words it’s wide along its y axis instead of its x axis like many bony fish.
  • They often come in a very pale bluish-grey color with a red dorsal fin that runs the length of its body. 
  • It’s head comes to a rounded flat side like a mahi-mahi and it has an upside down u-shaped frowny face mouth. 
  • They also have long red crests that come out of the tops of their heads and two pelvic fins are very long and thin. These pelvic fins are up close to the head. So the fish is mostly tail.

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. We do have a new Measure Up intro this week.

  1. Muscovy Duck
  2. Bean Goose
  3. Mute Swan
  4. Magpie Goose


  • They’re generally around 8 m (26 ft) but they may be as much as 11m (36 ft).
  • How many oarfish go into the longest oars on the Tessarakonteres, a greek catamaran galley from the Hellenistic period.
  • Hint: The Tessarakonteres was built by Ptolemy IV. The ship was reportedly so large that it was impractical and existed only as a prestige vessel.
  • 2.1 oarfish. Longest rowing oars were 38 cubits, 57 ft (17 m).


  • Maximum recorded was 270 kg (600 lb)
  • How many oarfish go into the weight of the water in the ocean?
  • Hint: A gallon of water is around 8.3 pounds (3.7 kg).
  • 4,869,333,333,333,333,333 oarfish (Four quintillion, eight hundred sixty-nine quadrillion, three hundred thirty three trillion, three hundred thirty three billion, three hundred thirty three million, three hundred thirty three thousand.)
  • There are 352 quintillion gallons in the ocean weighing around 2,921,600,000,000,000,000,000 lbs.

Fast Facts About the Oarfish

As with many animals that live in the pelagic zone in the ocean, the giant oarfish is very elusive. Adding to it’s off the grid nature, it also migrates constantly, following food sources. 

For that reason, we don’t know much about their behavior in the wild. The first reliable video of an oarfish came in 2010 when one was spotted in the Gulf of Mexico.

Oarfish have no teeth and instead have 40 to 50 gill rakers. These are bristly long things that are used for suspension feeding. 

Oarfish have been seen floating vertically with its tail down, and we don’t really know why they do this. Though it may be how they feed.

They feed on krill primarily, but they may also eat other small fish and squid.

Eggs are laid in the open water and they float near the surface until they hatch. The eggs are tiny, only 2.5 mm (0.1 inches) in diameter. 

Oarfish aren’t fished commercially, but they can be caught at bycatch. 

Because of their long shape, it’s thought that they are why people report sea serpents. 

Major Fact: Seismic Sensitivity?

Oarfish, and fish in general, are prominent in Japanese mythology, specifically their earthquake lore (and what mythology is complete without a robust helping of earthquake lore?)

For example, earthquakes are said to be caused by a country-sized catfish demon named Namazu that lives under Japan. Every time he shakes his tail, an earthquake shakes the islands. Oarfish are thought to be the messengers of Ryujin, the Japanese equivalent of Poseidon or Neptune. 

Since they live so deep, people rarely see these guys. When they do see them though, they’re considered harbingers of earthquakes, sent by Ryujin to warn people.

This was widely held even as late as 1855 when Tokyo was destroyed by a massive earthquake just after several oarfish were caught as bycatch in fishermen’s nets

However, just like most ancient mythologies, it fell into obscurity for the next century and a half until about a dozen oarfish washed up on Japan’s shores the year before the 2011 Fukushima earthquake.

This revived the myth – not that they’re the messengers of some ocean deity, but that they are like the canaries in the coal mine when it comes to earthquakes.So are they sensing tectonic movement or magnetic changes and trying to swim away from the ocean floor? Can we use the appearance of oarfish to predict and prepare for natural disasters?

Nope. There is no believable cause for these correlations outside of coincidence. So then why do they get stranded so often, and in “waves”?

There was a study done in 2018 showing a correlation between oarfish strandings and El Nino years.The temperature of the surface water gets a bit warmer during an El Nino, so the plankton and krill that the oarfish eat migrate up where the currents are stronger. Since the oarfish is a weak swimmer, only using its dorsal fin to propel itself, it can get exhausted fighting the currents.

Ending: So putz along in the depths, don’t get caught in stray nets, and warn humans of impending natural disasters like the oarfish here in LDT.