Deep Sea Ghost Shark: A Peculiar Creature of the Deep

Last Updated August 12, 2022

The most bizarre life forms are found in the deepest part of the ocean. According to NOAA, humans have only explored 20% of the sea — the other percentage remains unmapped and uncharted until this day. 

Among the elusive and mysterious creatures that lurk deep beneath its waters are ghost sharks, or also known as chimaeras — species that are believed to be one of the oldest fishes in the ocean. 

There are only a few human encounters with deep-sea ghost sharks. In 2009, their very first footage was caught by a group of researchers miles beneath the coasts of California. There we see how ghost sharks look and how they behave in their natural habitat. If you want to learn more about them, this post contains curious and amazing facts about this peculiar creature.


What are deep-sea ghost sharks?

Chimaeras or ghost sharks (scientific name: Callorhincus milii) are fishes from species that are relative to sharks and rays. They’re known in many different names such as “King of Herring”, “rat fish”, and “elephant fish”. 

All over the globe, there are over 50 known species of ghost sharks that vary from their elongated noses and tails. They are also divided into three groups — plow-nose, short-nose, and long-nose. 

Surprisingly, the species of chimaeras already exist even before there were dinosaurs. They’re known to have emerged after the Devonian extinction, which is approximately 420 million years ago. The earliest evidence of this species is the skull found in South Africa in the 1980s that researchers claim to be 280 million years old. 

Habitat

Deep-sea ghost sharks live 8,500 feet or 2,600 meters under the water and are thought to only exist in the Southern Hemisphere. Since they’re deep-dwelling in the ocean, they’re rarely seen alive. Their first sighting was from footage caught by an ROV where a pointy nose blue chimaera was filmed.

Other variations of this species can be spotted going to inshore bays during their mating season;  however, Chimaeras are confined to the deep sea since they live in rocky habitats such as the ocean floor. They also prefer cold water; thus why they’re seen in places like New Celadonia, Australia, and New Zealand (not including the Antarctic). 

Similar to other living organisms in the deepest part of the oceans, chimaeras also have what experts refer to as ‘Deep-Sea Gigantism’. It’s an occurrence wherein deep-sea dwelling animals are larger than their shallow-water relatives because of certain environmental factors such as: 

  • Food scarcity
  • Low predation
  • Increased oxygen concentration 
  • Extremely low water temperature

That said, ghost sharks or chimaeras can grow up to 4.1 feet (125 cm) to 4.9 feet (150 cm), with a maximum size that can reach 6 feet. They also have a life span of 15 years. 

Characteristics 

Chimaeras have a morphology that’s is unlike any other animals in this world. Similar to the Greek legendary monster of the same name, ghost sharks appear as if their parts come from different kinds of animals.

For one, they have teeth that resemble that of rodents. These consist of three pairs that continuously grow instead of falling off like sharks’ teeth do. Chimaeras are opportunistic feeders, and their teeth are made of mineralized tooth plates that they use to crush and munch on molluscs and worms. 

Depending on the variety of their species, some Chimaeras also have snouts similar to elephants, as well as nostrils that are very much alike to what mammals have. Unlike sharks that use their tails to propel themselves in the water, ghost sharks make use of their large dorsal fins to glide in the water — similar to how birds flap their wings.

Their name also fits their odd and creepy appearance.

Ghost sharks are known to have the slowest evolving genome in any of the vertebrates, a reason why they don’t look like any of the modern-day species. When inspected closely, it’s noticeable that chimaeras have strong resemblances with the animals from the Devonian period. 

Chimaeras are fishes that don’t have scales. Their colours vary from greyish-blue to brown. And instead of having multiple gills, they only have one external gill on each part of their body that also acts as their means of locomotion. 

Chimaeras’ skeletons are also a cross between cartilaginous and bony (like sharks), so they’re nearly impossible to fossilize. For this reason, there are only little known facts about this species until today. The only documented pieces of evidence about them are several video footage, dead carcasses washed ashore or caught by nets, and the fossilized skull found in the Karoo region, South Africa. 

How they adapt 

The eerie features of ghost sharks allow them to adapt to living in deep waters where the sun’s rays can’t penetrate. Their large eyes consist of reflective tissues called tapetum lucidum that glow underwater. These tissues also enable them to absorb as much light as they can. 

Ghost sharks have upper jaws that are connected to their skulls. Similar to sharks, they also have protruding snouts that are sensitive to electromagnetic fields and movements that help them when they’re hunting for prey. As their defence mechanism, chimaeras have venomous spines located on their first dorsal fins to protect themselves from other predators’ attacks. 

Chimaeras also have ghost-like movements that are quite hypnotic to look at. Typically, most animals who live in the deepest parts of the sea move slow because of the high pressure and cold extremity. However, in their case, they are able to move faster than others because of their large fins that allow them to cover more distance while using less energy. 

The lateral line canals of the chimaeras are another one of its many curious features. The dots, as well as the stitch-like looking lines that run on their entire body (more so in their head), are part of their sensory organs. Like their snouts, these are able to detect vibrations and movements in the water. 

Reproduction

Chimaeras are considered solitary animals based on how they’re always alone in their footage; however, that doesn’t mean that they don’t mate with other ghost sharks. 

The words ‘odd’ and ‘weird’ are accurate descriptions of how chimaeras mate. Instead of having their sexual organs located outside the pelvis and abdominal cavity like other animals do, male ghost sharks have their penises located on the top of their heads. What’s more unusual is that they are retractable, and their club-shaped male reproductive organs also include spines that are used to hold the female and position them better during copulation. 

Ghost sharks are oviparous reproducers, hence why the females release fertilized eggs during spring. The eggs they will lay are yellow, and will then settle to the sandy area of the ocean floor.

Egg incubation takes about 6 to 12 months. When they are hatched, the young fries will go to shallow waters first, and then progress to deeper parts of the ocean as they grow. 

However, since chimaeras reach sexual maturity late, they don’t reproduce as much as other sea creatures. They don’t lay a lot of eggs, too. These factors also contribute to why there are only a few encounters with them.

Conservation

The habitat of ghost sharks may be thousands of meters below the ocean, but that doesn’t guarantee their security from human intervention. 

During the pre-Columbian era, ghost sharks who end up being in shallow waters during summer are often caught in nets, dried, and then stored in kelp bags. In modern days, on the other hand, ghost sharks are targeted by small fisheries, especially the ones on the coasts of Canterbury and New Zealand where they’re often sold and exported in Australia. There they’re sold as silver trumpeters or whitefish fillets for fish and chips. 

Chimaeras are also in danger of boat trawling, a fishing method wherein one or two boats pull on nets to catch fish. Although some fishermen discard and throw them back to the sea, most chimaeras who end up being hauled die before they reach the surface because of the extreme changes in water pressure and depth. 


Conclusion

Even with the human’s most modern technologies, there is still a massive part of the ocean that’s still undiscovered. One of the creatures that we know very little of are the deep-sea ghost sharks or the chimaeras. 

Although peculiar and spooky, these fishes have astonishing characteristics that pique the human minds’ curiosity. Some of these characteristics are their physical features that look like they’re made from different parts of animals, as well as how they adapt to living in the deep sea.


Frequently Asked Questions

Q: Why are they called ghost sharks? 

Chimaeras, also known as deep-sea ghost sharks, are called such because of their ghost-like attributes like their eerie appearance and movements. The lateral line system that covers their bodies also gives spooky vibes because they resemble the ones Frankenstein’s monster has. 

Q: Are ghost sharks extinct? 

No. Chimaeras live in the deepest part of the ocean, thousands of meters below the water surface. According to Florida Museum, their population is stable, even if they don’t reproduce much. 

Q: Are ghost sharks edible?

Certain species of chimaeras can be eaten. For instance, small fisheries in New Zealand and the UK catch ghost sharks for export because they’re sold as whitefish fillets that are used for ‘fish and chips’.

Those that dwell in deep water, however, die as they’re hauled so they may not be as fresh. They may also be venomous because of their spines. 

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