Three new deep-sea shark species have been found off the coast of New Zealand and they all glow in the dark. Scientists were studying fish in the Chatham Rise off of New Zealand’s east coast when they made the incredible discovery.
The kitefin shark, blackbelly lanternshark, and southern lanternshark were glowing in the dark because of bioluminescence (biochemical emission of light by living organisms). The kitefin shark can grow as long as 180 cm (5.9 feet) which makes it the largest-known luminous vertebrate that has been found thus far (also known as the “giant luminous shark”). (Pictures can be seen here.)
Researchers from the Université Catholique de Louvain in Belgium and the National Institute of Water and Atmospheric Research in New Zealand noted that since the sharks live between 200 and 1,000 meters underwater in the mesopelagic zone (or “twilight” zone) of the ocean where the sunlight doesn’t reach, their glowing features may leave them vulnerable to possible predators.
On the other hand, since the kitefin shark probably doesn’t have to worry about predators, it may use its glowing underbelly to light up the floor of the ocean to search for lunch or perhaps to even camouflage itself while getting close to its prey. Other uses for their glowing features could be for mating and schooling.
The researchers wrote in part, “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.”
Jérôme Mallefet, who is the lead researcher from the Marine Biology Laboratory of the Université Catholique de Louvain in Belgium, stated, “The luminous pattern of the Kitefin shark was unknown and we are still very surprised by the glow on the dorsal fin. Why? For which purpose?”
Mallefet went on to say that as many as 10% of all shark species may be able to produce bioluminescent light. As for the three that were discovered in Chatham Rise, he described their blue-green glows, “They are glowing in the dark. They are not producing flashes. They are glowing for a long time.”
While more studies need to be conducted in order to better understand their bioluminescence, this is a very interesting discovery off the coast of New Zealand and perhaps the researchers may find even more glow-in-the-dark sharks.
As a matter of fact, there are numerous bioluminescent creatures living off the coast of New Zealand, such as fungi, glow-worms, and even a large glowing earthworm. Microbiologist Dr. Siouxsie Wiles explained this in further detail, “What we know is that [bioluminescence] evolved many times, and creatures don’t use the same ways to make light.” However, the cells on the sharks that magnify the light are controlled by their hormones which Wiles described as being “...quite different to other bioluminescent creatures.”
The study was published in Frontiers in Marine Science where it can be read in full.