Will ghost sharks vanish before scientists can understand them?
Take one look at a ghost shark and you may say, “What’s up with that weird looking fish?”
Over the past few decades, scientists learned that these cartilaginous fishes, also known as ratfish or Chimaeras, have been around for hundreds of millions of years and that they have venomous spines in front of their dorsal fins and “fly” through the water by flapping their pectoral fins.
Unusual aspects
They even learned that most male ghost sharks have a retractable sex organ on their foreheads that resembles a medieval mace.
However, much remains to be learned about these strange creatures.
Basic biological information, like how long they live and how often they reproduce, is lacking for most of the 52 known species.
The absence of this key information makes it difficult for scientists to manage and monitor ghost shark populations, even as evidence mounts that some species may be at risk of extinction.
Scientists from the Shark Specialist Group, a division of the International Union for the Conservation of Nature, recently assessed the extinction risk of all confirmed ghost shark species and determined that 16% are “threatened” or “near threatened.”
The assessment, which was published in the journal Fish and Fisheries, also found that 15% of ghost shark species are so understudied that their extinction risk cannot be determined.
Experts’ concerns
Now experts are concerned that certain ghost shark species might go extinct before scientists have a chance to study them.
Ghost sharks can be found in all of the world’s oceans, except the Arctic and the Antarctic.
Most inhabit the deepsea, although a handful of species inhabit shallow coastal waters.
Not true sharks
Despite their name, ghost sharks are not true sharks, though they are closely related. Unlike their shark cousins, ghost sharks have long, thin tails and large, continuously growing tooth plates that give them a ratlike appearance.
Some have long skinny snouts while others sport plow-shaped ones that they use to probe seafloor sediment in search of food.
“They’ve got a face only a mother or a researcher could love,” said David Ebert, director of the Pacific Shark Research Center at Moss Landing Marine Laboratories and co-author of the assessment.