This deep-sea shark is one of the world’s largest glowing animals
Shark researchers working off the eastern coast of New Zealand have made an illuminating discovery. In a new study, published in the journal Frontiers in Marine Science, the scientists found that three species of deep-sea shark are bioluminescent, producing a soft blue-green light with specialized cells in their skin.
One of the species, the kitefin shark, grows to a length of nearly six feet, making it the largest known bioluminescent vertebrate. Giant squid, which get much bigger, are also known to produce light.
Bioluminescence had previously been documented in only around a dozen shark species, so this discovery significantly adds to our knowledge of how prevalent the phenomenon is in these and other marine animals, says Jérôme Mallefet, a research associate at the Université Catholique de Louvain in Belgium and lead author of the new study.
The expedition involved hauling up a small number of blackbelly lanternsharks, southern lanternsharks, and kitefin sharks from the ocean’s twilight zone, a scantly illuminated region that extends from a depth of 660 to 3,300 feet.
When Mallefet obtained a kitefin shark and saw it light up aboard the research vessel, he was overwhelmed. “I nearly cried when I saw it … it was so exciting,” he says.
The other two species are somewhat smaller than the kitefin, and all are occasionally caught as unintended bycatch by fishers. None are considered vulnerable to extinction, but little is known about their lifestyles and biology.
Diva Amon, a deep-sea biologist and National Geographic emerging explorer who was not involved in the study, says she was “awestruck” by the discovery. “These findings remind us about how much we still have to discover and understand about the deep ocean and its inhabitants,” she says.