Researchers photographed a glow-in-the-dark shark nearly 1,000-feet below off the coast of New Zealand. This is the kitefin shark that can grow up to six feet long.
The researchers also discovered two more glow-in-the-dark sharks, namely the blackbelly lanternshark and southern lanternshark who also possess bioluminescence. All of the three sharks live in the 'twilight zone' which stretches 3,200 feet below sea level that is out of sunlight's reach, MailOnline reported.
The species were not new but it is the first time their luminescence characteristics were photographed. The kitefin shark is said to be the largest known bioluminescent vertebrae.
The study is entitled "Bioluminescence of the Largest Luminous Vertebrate, the Kitefin Shark, Dalatias licha: First Insights and Comparative Aspects" and published in Frontiers in Marine Science.
Using Bioluminescence as Camouflage
Researchers from the Universite Catholique de Louvain in Belgium and the National Institute of Water and Atmospheric Research in New Zealand said that the three glow-in-the-dark shark species are bioluminescent, which means they produce their own light.
CNet reported that these species need this bioluminescent characteristic to survive the ocean's twilight zone that is 656 feet to 3,280feet (200 m to 1,000 m) below the surface.
Moreover, it also serves as their camouflage to hide from predators. Although this seems to be illogical, the researchers claim that the light from the three shark species plays against the faint glow from the surface of the ocean and helps hide them.
This is the first time that the bioluminescent characteristic of sharks has been photographed although many marine species, mammals, and reptiles are known to glow-in-the-dark. During the lockdown in 2020, bioluminescent plankton reportedly light up Puerto Marques Beach at Acapulco.
According to MailOnline, this phenomenon is known as the 'living light' or 'cold light.' A molecule called luciferin creates chemical reaction in the fish that produces the bioluminescent light as a reaction to light.
Study lead researcher Jérôme Mallefet from the Université Catholique de Louvain's Marine Biology Laboratory said that 57 out of 540 known shark species are thought to be capable of bioluminescence, 9News reported. But since they live deep in the sea, it is difficult to see these glow-in-the-dark sharks.
Using Bioluminescence To Find Food
Researchers said that it is also possible that kitefin sharks use bioluminescence to illuminate the ocean floor while it searches for food. Kitefine sharks have few or no predators and mostly eat other sharks, like its fellow study topic the lanternshark, according to CNet.
"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," the researchers wrote.
Mallefet said that he and his team hope to be back at sea soon and find more luminous creatures.
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