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What is an Oarfish?

R. Britton
R. Britton

The oarfish is thought to be the longest known species of bony marine fish. It has a long, thin body growing to more than 36 feet (11 m). The oarfish has a scaleless silver body with black to brown markings along the sides. It has a large dorsal fin that starts at the head and runs the length of the oarfish's body. The dorsal fin ranges in color from bright pink to deep red. Until the first video footage was captured of a live oarfish, it was widely thought that the fish propelled itself through the water by undulating its whole body; it is now known this is not true and that they actually propel themselves by undulating the dorsal fin while the body remains mostly stationary.

Caught on film by the United States Navy for the first time in 2001, the oarfish remains a modern day mystery. Although there are occasional sightings, there has been no conclusive research into the life of this species. This fish is thought to only be found on the surface when ill or close to death, and the majority of information gathered comes from the examination of dead specimens found washed ashore on beaches across the world. Sometimes caught by recreational fishermen, the oarfish is not commercially fished because the flesh is unpalatable.

An oarfish's diet might include small squid.
An oarfish's diet might include small squid.

Regalecus glesne is the scientific name given to the giant oarfish. There is a debate within the scientific community surrounding whether there is only one true species or up to four known species. So little is known about the oarfish that it is difficult to know for certain. Differences between specimens could just be a result of localized adaptations of the same species across such a large geographic range. Differences in markings could also be localized variations, and it is known that the markings fade and disappear after death, which could be another factor in species recognition.

The oarfish is thought to be a solitary creature, living in all temperate to tropical oceans. It is to be found at depth of 600 feet (200 m) to more than 3,000 feet (1,000 m). This species is thought to be predominantly carnivorous, eating plankton, squid and smaller fish. Oarfish are not listed as endangered, largely because not enough is known about their numbers and any potential threats to the population to make an accurate judgment. The size and bizarre, somewhat menacing appearance of the oarfish, as well as the rarity of sightings, had led to a widely held theory that sightings of oarfish gave rise to the widespread myths about sea monsters and giant sea serpents.

Frequently Asked Questions

What is an Oarfish and where can it be found?

An Oarfish is a rare, elongated fish that inhabits the deep, pelagic waters of the world's oceans, typically at depths between 200 and 1,000 meters. They are most commonly found in temperate to tropical oceans but are rarely seen due to their deep-sea habitat. Oarfish are known for their ribbon-like appearance and can grow to impressive lengths, with some reports of individuals reaching up to 36 feet (11 meters).

How does the Oarfish move in the water?

The Oarfish moves in a unique, undulating manner, propelling itself through the water with wave-like motions of its elongated dorsal fin. This fin runs along the length of its body, allowing the Oarfish to maintain a vertical position in the water. Their movement is graceful and energy-efficient, which is essential for survival in the nutrient-sparse deep sea.

What do Oarfish eat?

Oarfish are believed to be planktivores, feeding primarily on tiny plankton, jellyfish, and small crustaceans. They likely drift through the water, consuming prey directly in their path. Due to the scarcity of food at the depths they inhabit, Oarfish have adapted to a diet that consists of readily available, small organisms.

Are Oarfish dangerous to humans?

Oarfish pose no threat to humans. They are not aggressive and have no known venomous traits or dangerous behaviors. Encounters with Oarfish are extremely rare due to their deep-sea habitat. When Oarfish are found near the surface or washed ashore, it is often because they are sick or dying, which further reduces any potential threat to humans.

Why are Oarfish often associated with earthquakes and tsunamis?

Oarfish are sometimes called "earthquake fish" due to a Japanese folklore that associates their beaching with imminent earthquakes or tsunamis. However, there is no scientific evidence to support this belief. It is speculated that seismic activity may affect deep-sea creatures, but no direct correlation between Oarfish sightings and seismic events has been proven.

How do scientists study Oarfish if they live in deep water?

Studying Oarfish is challenging due to their deep-sea habitat. Scientists often rely on remotely operated vehicles (ROVs) and deep-sea submersibles to observe and collect data on these elusive creatures. Occasionally, dead or dying Oarfish wash ashore, providing researchers with rare opportunities to examine them directly. Advances in deep-sea technology continue to improve our understanding of Oarfish and their environment.

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    • An oarfish's diet might include small squid.
      By: hiphoto39
      An oarfish's diet might include small squid.