Largest ever glow-in-thedark shark is discovered
THE largest known shark that can glow in the dark has been found by researchers off the coast of New Zealand.
Scientists discovered that three species: the kite-fin shark, the blackbelly lantern-shark, and the southern lantern-shark emit a luminescent glow in their habitats deep below the surface of the ocean.
All three deep-sea sharks, which live at depths between 200m and 1km, were known to science already, but their ability to glow was not documented.
The three species were collected during a survey in eastern New Zealand in January last year, and were observed in tanks before being dissected and analysed.
One of them, a kite-fin shark, which can reach up to 1.8m (5ft 10in) long, is now the world’s largest known luminous vertebrate, said the paper published in the journal Frontiers in Marine Science. It is also the first documented shark with fully luminous dorsal fins.
The researchers believe that kite-fin sharks, which have few if any predators, use their glowing ability to camouflage themselves from prey and to illuminate the ocean floor while hunting, but said more evidence was needed to confirm this theory.
“The use of counter-illumination for this giant luminous shark is here suggested to be co-opted for a camouflage-type approach as a predatory tool,” the researchers said.
Lead author Jérôme Mallefet, of the
University of Louvain-la-neuve in Belgium, said the sharks used a different mechanism to glow than other bioluminescent animals. “The sharks discovered off New Zealand in January 2020 control their light production system by hormones, while most of the bioluminescent organisms seen to date use nerve control to trigger their light,” he told Belgian broadcaster RTBF.
The researchers concluded that bioluminescence plays a greater role than previously thought in deep-sea ecosystems.
Other luminous marine creatures include some species of algae, crustaceans and jellyfish, and the ability serves different purposes for different species. Some prey animals, such as jellyfish, use the function to startle predators and attract other creatures that prey on their predators.
The bizarre creatures found in the depths of the ocean aren’t usually known for their beauty. The pudgy cusk eel is about as attractive as the name suggests. Nor will the blobfish or the goblin shark be winning pageants anytime soon. Which puts the kitefin shark, which lives off New Zealand, in a league of its own. The predator, which can grow to 180cm, is the biggestknown luminous vertebrate – or, as the learned researchers aptly put it, a “giant luminous shark”. Its eerie glow is thought to be a form of camouflage, or for illuminating the ocean floor when hunting. But galeophobes needn’t fear coming across one, the next time Jacinda Ardern allows visitors to her pristine country: they live up to 1,000m deep. How else would they have kept researchers in the dark for so long?