New discovery of 2 rare skate sharks found in Alaska, British Columbia
New deep-sea findings by scientists reveal two rare shark species have been found for the first time in Alaska and British Columbia waters.
Scientists from the National Oceanic and Atmospheric Administration in Alaska and British Columbia teamed up to identify the new sharks, according to the NOAA Fisheries website.
The fine-spined skate and the Pacific white skate are usually only seen in Costa Rica and Washington, but a young male Pacific white skate showed up in a recent 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 said they had to wait to work with a geneticist to identify it.
While those researchers were busy, Canadian scientists made their discovery of a Pacific white skate as well — an adult male representing a new record for the species in British Columbia, according to an abstract of the study published in Northwestern Naturalist.
Researchers from Fisheries and Oceans Canada collected five other adult male fine-spined skates in a survey off the west coast of Vancouver Island. Biologist Jim Boutillier, from FOC, turned over his sharks to the Royal British Columbia Museum.
Fine-spined skates are the deepest-dwelling skate in the world. They can be found at depths of more than two miles below the ocean's surface. While the Pacific white skate is the second deepest-dwelling skate, able to reach depths just short of two miles.
Orr notes their preference for deep oceans may explain why these two species have been rarely recorded or encountered by humans.
Scientists from both groups used genetics to look at the skates' shapes and features to identify the species.
Orr said in the post from NOAA Fisheries that geneticist Ingrid Spies, of AFSC, played a major role in identifying the sharks.
“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," Orr explained. "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.”
The team of researchers identified the juvenile male skate from the Bering Sea as a Pacific white skate by comparing data from a juvenile male in Costa Rica and matched the structural biology to their shark.
Orr said the discovery was the first record of the species for the Bering Sea and for Alaska.
Scientists are confident this Pacific white skate must have been spawned in the Bering Sea because it was a young, newly hatched male.
As for British Columbia scientists, their five skates also set a new record. These sharks had been misidentified as Okhotsk skates, a species typically known from the western Pacific and western Aleutians. Orr thought something wasn't quite right though.
"We were suspicious because they were collected far from the known range of Okhotsk skate and at a much greater depth—more than 1,000 meters deeper," he said in NOAA's post.
After the scientists saw the sharks in person, they knew they were not the Okhotsk skate, according to Orr. The RBC Museum did genetic testing and find all five were fine-spined skates, leading to the first record of the species in British Columbia.
So what's a skate shark and why are they important?
Skates are sometimes called "flat sharks," according to NOAA. They are characterized by their notably, flat bodies, they also have five- to seven-gill slits and toothlike scales covering their bodies. Another distinction is their skeletons are made of cartilage instead of bones.
These sharks play a big role in maintaining the health of ocean ecosystems in the Bering Sea and the North Pacific Ocean. Many skates are caught as bycatch in fisheries targeting other fish. Orr says it's important to know what skate species there are and knowing where they live is crucial to understanding the ecosystem and how to effectively manage them.
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