A ghost shark, officially called chimaera. Credit: University of Florida
This summer season, a team of researchers from the University of Florida and the Seattle Aquarium is plunging 100 meters below the waves in the Pacific Northwest to investigate the enigmatic ghost sharks, one of the oceans strangest deep-sea animals.
The scientists are utilizing Remotely Operated Underwater Vehicles (ROVs) in their quest to locate the reproducing habitats of the Pacific found ratfish, Hydrolagus colliei, a ghostlike fish that lurks on the ocean floor.
” We understand really little about these elusive family members of sharks and even less about their spawning habits and embryonic advancement,” stated Gareth Fraser, an assistant teacher of biology at UF, before leaving for the expedition. “We will release ROVs to search for where these ghost sharks lay their eggs.”
Related to rays and sharks but separated by almost 400 million years of development, ghost sharks– officially called chimaeras– are one of the most enigmatic and understudied group of fishes, Fraser stated. They have ever-growing tooth plates like a rodent, which is why they are frequently called ratfish. While shark skin is covered in teeth, chimaeras have no teeth on their skin, and the males have a giant bulb on their forehead called a tenaculum that grows spiky teeth that look like shark teeth.
” We think they utilize this head clasper like a 2nd jaw on their head to bite down and attach to the female throughout copulation,” Fraser described. “Ghost sharks are a really strange group of shark family members whose biology makes them a bit other-worldly.
The ghost shark up close. Credit: University of Florida
Related to rays and sharks but separated by nearly 400 million years of evolution, ghost sharks– formally called chimaeras– are among the most enigmatic and understudied group of fishes, Fraser said. They usually live in deep waters, which is why researchers dont understand much about them. Nevertheless, there are a few places in the world, including in the Salish Sea along the coast of Washington, where chimaeras will enter more shallow waters to feed and reproduce, specifically throughout the summer season.
” If we can locate their embryos, we can begin to find out about the developmental procedures that cause some odd morphologies, or biological attributes, unique to these fishes,” Fraser said.
UF biologist Gareth Fraser holds a ghost shark. Credit: University of Florida
Chimaeras have big round eyes like a rabbit that permit them to see as they creep in the dark hunting for food. They have ever-growing tooth plates like a rodent, which is why they are typically called ratfish. While shark skin is covered in teeth, chimaeras have no teeth on their skin, and the males have a giant bulb on their forehead called a tenaculum that grows spiky teeth that appear like shark teeth.
” We think they use this head clasper like a second jaw on their head to bite down and connect to the female throughout copulation,” Fraser discussed. “Ghost sharks are a very odd group of shark relatives whose biology makes them a bit other-worldly. When we get an opportunity to find these odd fish where they breed and feed, we have to go for it.”
The ghost shark male has a huge bulb on its forehead called a tenaculum. Credit: University of Florida
Fraser and others throughout the globe have actually had success in the last year with deep-water trawling jobs finding adult ghost sharks, but studying older fish does not shed much light on their developmental processes. This summer seasons undersea search for the ghost shark nesting areas is the very first of its kind for this species.
” We found a lot of various stages of the fish in 2015, from freshly hatched infants to completely mature grownups, so this year, were going back to find their nursery grounds,” Fraser said.
UF biologist Karly Cohen runs the ROV from a pier in Seattle. Credit: University of Florida
The ghost shark expedition task is supported through funds from a National Science Foundation grant concentrated on the skin teeth of sharks and Frasers UF start-up grant. The group wants to discover tricks about the origins of teeth, which could help them find out more about how to regrow human teeth.
The four-day expedition began June 11 in Seattle, with the team on a pier running the ROV, which is basically an undersea drone, that traveled about 10 meters deep in search of the ghost shark nesting sites.
The male ghost shark reveals its tenaculum. Credit: University of Florida
In the coming weeks, the group will release the ROV about 100 meters deep from a boat in Elliot Bay in Puget Sound, and other sites around the San Juan Islands. Covered in electronic cameras that will deliver 360-degree views, the ROV will capture images created to create a virtual reality scene of the depths of the ocean for scientists once they are back in the lab.
” This will take us to the waters off Washington state so that we can swim with these ghost sharks practically and get an up-close, scenic view of their environment,” Fraser said.
Karly Cohen, a UF biology postdoctoral fellow in the Fraser Lab who originally located the prospective ghost shark nursing sites, said their project is an excellent opportunity to help enhance preservation efforts.
” Its essential to discover these understudied deep-water fish and their reproductive methods,” she said. “Ultimately, we wish to secure this truly charming types.”
The research was moneyed by the National Science Foundation.
