Oarfish

The Giant oarfish (Regalecus glesne) holds the Guinness Book of World Records for the longest bony fish in the world. They are found in the depths of the Mediterranean Sea and the eastern Atlantic Ocean and have a ribbon-like appearance.

Oarfish are members of the Regalecidae family and are also known as the King of Herrings because their dorsal fin looks like a crown. Their dorsal fins run down the entire length of their gigantic bodies, with a tiny spine located above 400 individual fin rays.

The oarfish’s pelvic fins are elongated and similar in color to their bodies. The King of Herrings is a rare species because it primarily inhabit deep sea waters.

They move their pelvic fins in a circular motion, very similar to an oar, hence the name. These unique fish use their dorsal fins to help them swim and swim in a vertical position.

Three Amazing Oarfish Facts

• The oarfish resembles a giant snake or dragon because of its elongated body. In addition, they are smooth and lack scales, with tubercles and a guanine coat topped with ornate markings and a red dorsal fin.
• Their flesh is sought after by fishermen because it is so rare. The texture is sticky and jelly-like
• There is a superstitious folklore in Japan that when an oarfish washes up dead on the shore, it’s considered a sign of impending doom, like a Tsunami or Earthquake. For example, 20 dead oarfish washed up on shore just before Japan’s 2011 tsunami.

Classification and Scientific Name

Oarfish belong to the order Lampriformes, and while families of this order don’t look alike, they all share the following characteristics that distinguish them from other orders of ray-finned fishes:

• Compressed body
• Ribbon-like appearance
• No true spines on fins; rays only

The oarfish are members of the Regalecidae family, consisting of small oceanic fish with elongated, ribbon-shaped bodies. In addition, their upper dorsal fin rays are longer than the others and contort into a crown or crest above the head. The pelvic fins only have a single ray trailing below the body.

There are only three species of oarfish, and they include:

• The Giant Oarfish (Regalecus glesne)
• The streamer fish (Agrostichthys parkeri)
• Russell’s Oarfish (Regalecus russeii)

Giant Oarfish

Giant oarfish is a species of bony fish that got its name from the shape of its pelvic fins, that it rotates like an oar. They are often compared to monsters because of their elongated bodies and massive size. The giant oarfish can grow to lengths of 56 feet and can weigh a whopping 600 pounds.

They have flat, long tapering bodies that are reflective silver in color, and a dorsal fin that runs down their entire body, which they use to help them swim.

These giants are deep-sea fish that occur in the Gulf of Mexico. They go by many names, which include:

• Ribbon Fish
• Streamer Fish
• King of Herrings
• Pacific Oarfish

In addition, many people refer to them as sea serpents because they look so similar when they appear close to the surface.

The fin rays near their heads lengthen to form a distinctive, bright red crest that has evolved over many years to act as a defense mechanism against predators.

An interesting fact about oarfish is that most of their organs are situated close to the head, so even if their elongated tails are cut off, they can still survive.

Giant oarfish live in the deepest depths of the ocean, but sometimes, when they die, they wash up on shore, especially after a brutal storm.

Appearance

The oarfish’s most distinctive feature is its elongated body. However, they are rarely seen because they inhabit the deepest depths of the ocean.

Oarfish have a reflective silvery color, and their skin is rubbery and smooth (they have no scales). Their bodies are covered in wavy markings and coated in guanine, which is one of the building blocks of DNA and RNA.

Unlike most fish, oarfish don’t have anal fins; instead, they have a long dorsal fin, which runs down their entire body. Their pectoral fins are located on the lower part of their bodies.

An interesting fact about the oarfish is that its mouth is capable of extending or protruding. And while the sea serpent is not real, many people believe their myth originated with the giant oarfish because of their massive size and snake-like appearance.

The giant oarfish holds the record for the longest bony fish in the world. They can grow up to 56 feet long and weigh up to 600 pounds.

Behavior

There is very little research about the oarfish’s behavior. In fact, marine biologists did not record this species in their natural habitat until 2010.

They use their elongated dorsal fin to help them swim in search of prey. But their swimming style is very unusual. They swim horizontally with their bodies in a column-like position, with their heads facing upward and tails downward.

Habitat

Oarfish are native to the western Indian Ocean, southwest Pacific, northeast Atlantic, western central Atlantic, eastern central Pacific, northwest Atlantic, Mediterranean, and the Black Sea, western central Pacific, eastern central Atlantic, southeast Atlantic, southwest Atlantic, and the east Indian Ocean.

The giant oarfish inhabit pelagic waters (deep waters) or open oceans. Which means they do not occur close to the coast. They are mainly found in the mesopelagic and epipelagic zones of the deep sea.

These serpent-like fish live in habitats as far down as 3,000 feet, and the shallowest waters they inhabit are around 600 feet below the surface.

Diet

Oarfish are carnivores, but despite their massive size, their prey is primarily small marine creatures. The main component of their diet is krill; however, they also feed on:

• Shrimp
• Plankton
• Squid
• Small fish

Unfortunately, because researchers have only observed a few live specimens, there is very little information about their hunting behavior. However, researchers have observed the oarfish eating by suctioning prey like plankton blooms while in the water.

Predators and Threats

While not much is known about this pelagic fish, they likely fall prey to large open-ocean carnivores like Great White Sharks and Orcas.

These massive creatures have no known significant threats. Most of them die from natural causes or predation, and their bodies often float to the surface or wash up on beaches.

Giant oarfish are sometimes caught in nets meant for other species;  however, these are very rare occurrences, and it does not affect their overall population numbers. In fact, the IUCN has listed them as Least Concern on their Redlist.

Reproduction, Babies, and Lifespan

Oarfish are oviparous and reproduce by releasing their eggs and sperm into the ocean. Spawning takes place during July and December once the temperatures begin to rise.

The eggs lay on the surface until they hatch and develop into larvae within 3 weeks. Juveniles have distinctive long rays on the pelvic and dorsal fins. Once they grow up, they live a solitary life.

Population

There are no definitive estimates of the population size of this fish. They have three species with two genera, and sightings of any of these three species are very rare.

Importance to Humans

These massive fish are not of commercial value due to their location deep within the ocean and their poor quality of meat, which has a gelatinous texture and is considered inedible. However, some consider them game fish, and they catch them with encircling nets, where they market them fresh in some local areas.

But, in general, they are rarely observed by humans, only when swimming on the surface or washed up dead on the coasts. The first time one was caught on film was in 2001 by the US Navy.