On Earth, there are places where the pressure is so great that it can crush steel. No light penetrates there and the temperature is close to zero… it’s an abyss. These vast depths (however inhospitable) occupy two-thirds of the planet and are home to many forms of life, much of which remains a mystery to science.
Among them, the “Ghost Fish” belongs to the Aphyonidae family and had never been seen in its natural habitat before 2016. Forbes Magazine reported that that year, during an expedition carried out by the American Oceanic and Atmospheric Observatory (NOAA), researchers managed to film specimens at a depth of about 2,500 meters.
The “ghost fish” were later discovered along a ridge at the bottom of the Mariana Trench, the deepest ocean trench known to date, located in the northwestern Pacific Ocean. The specimen observed was only 10 centimeters long. To date, this exploration video recording is the only video recording of a member of the Aphyonidae family.
Previous knowledge about this family of fish came from analysis of specimens caught by trawls, making it difficult to learn more about their lifestyle and habitat. Images from 2016 show that this fish lives very close to the seabed and not in open water.
A huge hidden ecosystem
These “ghost fish” are only a finger long, almost completely transparent, and appear to glide rather than swim. Its skin was gelatinous, devoid of scales, and its eyes were very small, making it look more like a wandering spirit than a fish. These common traits shared by other abyssal creatures are what inspired its name for researchers.
Observations of these specimens have brought many benefits to the world of marine biology, particularly by highlighting how fragile certain abyssal species are. This also adds to our knowledge of fish evolution, because aphyonids are close relatives of Ophidiidae, which are also nicknamed “Damsels”. But they diverged in surprising ways, losing scales, reducing the size of their eyes, and changing much of their body structure, to adapt to the deep sea environment.
This observation also reminds us how limited our knowledge of ocean depths is, because more than 80% of the deep ocean remains unexplored to date. Therefore, this is a small discovery in a vast ecosystem that is still hidden.
Finally, this exploration is a reminder that advanced remotely operated underwater vehicles have revolutionized marine science. The discovery of the little ghost was possible thanks to this type of device, which was used by the NOAA ship, Okeanos Explorer. Without robots capable of operating under extreme stress, the existence of creatures like the “Ghostfish” may only be hypothetical, as science has yet to find another way to observe them in their natural habitat.
