A species of shark that glows in the dark have been found off the coast of New Zealand
Scientists say they discovered three deepwater shark species from the Chatham Rise, an area of ocean floor to the east of New Zealand, in January last year.
Largest known luminous vertebrate
One of the species, the kitefin shark, is now the largest known luminous vertebrate and can grow up to 180cm long (5ft 11in).
Bioluminescence (organisms emitting light) was also found in the blackbelly lanternshark and the southern lanternshark.
All three species were already known to marine biologists, but the discovery marks the first time that bioluminescence has been identified in them.
The ability to glow in the dark is achieved via thousands of light producing cells which are located within the shark’s skin.
Several other marine animals, along with some insects like fireflies, have the ability to produce their own light, but this is the first time it has been found in larger sharks.
Researchers have suggested that the glowing underbellies of the sharks may be used to help them hide from predators, or other threats which lurk beneath them.
Found in the twilight zone
The three species of shark inhabit a space called the mesopelagic zone, also referred to as the twilight zone.
This area ranges between 200m to 1,000m in depth, which is the maximum depth reached by sunlight.
Researchers say that these species face an environment in which there is no place to hide and so use counterillumination as a form of camouflage to protect them from predators.
The study, published in Frontiers journal Marine Science, explains that bioluminescence is important for many marine creators.
Scientists from the Université Catholique de Louvain in Belgium and the National Institute of Water and Atmospheric Research in New Zealand said: “Bioluminescence has often been seen as a spectacular yet uncommon event at sea, but considering the vastness of the deep sea and the occurrence of luminous organisms in this zone, it is now more and more obvious that producing light at depth must play an important role structuring the biggest ecosystem on our planet.”