Discovered in the deep: the sharks that glow in the dark

Measuring up to 1.8 metres, kitefin sharks are by far the biggest bioluminescent sharks to have been found? Discovered in the deep: the 'mermaid's wineglass' single-cell organismKitefin sharks (Dalatias licha) have been known about since the 18th century, but it was only in January 2020 that scientists saw them glowing in the dark for the first time. They are not the only bioluminescent sharks - roughly one in 10 species has that ability - but at up to 1.8 metres, kitefins are by far the biggest that have been found.Jérôme Mallefet, a biologist at the Université catholique de Louvain, Belgium, had been hoping for years to see a glowing kitefin shark. "That was one of my holy grails, to see that big shark glowing," he says. Studies in the 1980s suggested they have light-emitting organs in their brown skin, but nobody had seen one alive and illuminated.His dream came true 1,000 miles east of New Zealand, onboard a fisheries research vessel that was using a huge, commercial-scale trawl net to survey species inhabiting the twilight zone, about 800 metres down. Previous surveys of the area regularly caught kitefin sharks, but Mallefet was the first person to carefully transfer them into a darkened room. With the lights turned down low, he saw the live kitefin sharks had a blue-green glow across their bodies. Continue reading...