Two rare, deep-dwelling skate species have been recorded for the first time in Alaska and British Columbia waters: the fine-spined skate and the Pacific white skate.
Sharks and Skates: How are They Related?
Skates are sometimes called "flat sharks." They are all elasmobranchs: fish characterized by their cylindrical or flat bodies, five to seven-gill slits, and toothlike scales.Their skeletons are made of cartilage instead of bones.
The fine-spined skate is the deepest-dwelling skate in the world, found at depths more than two miles below the ocean surface. The Pacific white skate is the second deepest-dwelling skate, reaching depths just short of two miles.
Only a few specimens of these two species have ever been collected by scientists at locations, ranging from Costa Rica to Washington State.
That was until a young male skate came up in a deep trawl during a survey of the Bering Sea Slope.
“Jerry Hoff, an expert on Alaska skates, was on board and saw immediately that this was something different,” said research leader Jay Orr. Both Hoff and Orr are biologists at the Alaska Fisheries Science Center. “But we had to wait to identify it until we had a geneticist to work with.”
Meanwhile, Canadian scientists collected five unusual adult male skates from one slope survey trawl off the west coast of Vancouver Island. Biologist Jim Boutillier from Fisheries and Oceans Canada returned them to the Royal British Columbia Museum, under the care of Collection Manager Gavin Hanke.
An International Collaboration
Alaska Fisheries Science Center and Royal British Columbia Museum scientists joined forces to identify the new skates. They used genetics and morphology—looking at the skates’ shape and features.
“It’s an exciting collaboration,” said Orr. “In recent years we’ve developed a strong relationship with the Royal British Columbia Museum. We’ve been working together in the Salish Sea and Alaska as well.”
Geneticist Ingrid Spies of the Alaska Fisheries Science Center played a key role in the investigation. Orr explains:
“Skates are difficult to identify because they are all morphologically similar: flat and dully colored. The only characters we can use to identify them are thorns on the dorsal side and some general color patterns. So genetics provide a lot more information to differentiate species. Ingrid had already barcoded all of the 15 known skate species in Alaska. She could genetically confirm our identifications of the new species.”