The unusual-looking and extremely elusive ghost shark dwells in the darkness of the deep sea, rarely revealing itself – just like a phantom, or ghost. But now we finally have it on camera.
The rarely seen abyssal ghost shark (Hydrolagus trolli) is, as its name suggests, a ghost-like deep sea fish in the genus Chimaera that can be found in most of the world’s oceans. Scientists have been unable to capture this elusive creature on camera, since they prefer depths up to 8500 feet (2600 meters), although some have been observed in more shallow waters as well.
However, geologists of Monterey Bay Aquarium Research Institute in California were able to record the rare fish in its natural habitat for the first time by pure luck, when they were conducting deep-water surveys with a remotely operated vehicle not far from California and Hawaii. The scientists didn’t expect to come across anything extraordinary in these depths, but to their surprise, a rather peculiar fish kept popping up around the ROV.
Experts were able to identify the mysterious deep-sea creature as a pointy-nosed blue chimaera, which can normally be found near Australia and New Zealand. So, this accidental discovery was not only the first time this species of ghost shark was captured on video, but also proves that it can be found in the Northern Hemisphere as well.
While ghost sharks are not actual sharks, they are closely related – their last common ancestor separated from sharks around 400 million years ago. Since they were around even before the dinosaurs, and survived their extinction, Chimaera species are among the oldest fish that are still swimming in the oceans today.
On average, chimaeras are not very large, but some subspecies can grow up to 6,6 feet (200 centimeters) in length. The lines, that make the Chimaeras look like they were stitched together, cover the whole body of the fish, but mostly their head. While it’s a cool-looking feature, these “stitches” have a very important purpose as well. They are sensory organs that can pick up movements and vibrations in the water. This helps the ghost shark to be more effective at catching its prey – mollusks, worms, and other invertebrates – in the pitch-black environment of the deep sea. And, perhaps even more interestingly, male chimaeras have retractable sex organs on their foreheads.
Most of these animals also have an impressive defensive mechanism against other predators. In front of their dorsal fins, they have an elongated venomous spine, that is sufficient enough to even badly injure humans.
Due to the fact that the dark realms of the deep sea are quite hard to reach for humans, there’s still a lot we don’t know about the ghost shark. Some scientists even speculate that a few Chimaera species may even go extinct before we could even identify them.
We do hope, though, that these one-of-a-kind fish will have a future at least as long as their past.