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All in the name of science: experts dissect great white shark that washed up on Cape Cod

A 7 1/2-foot juvenile male shark was found in Barnstable during the July 4 holiday weekend. Scientists took it apart during a necropsy to advance their knowledge of the species.

Scientists and researchers performed a "necropsy" on a great white shark on July 5. The shark washed up in Barnstable.John Chisholm/@MA_Sharks

Greg Skomal spends much of his summer racing around on a boat on the outer banks of Cape Cod while wielding a long pole with a tracking device at the end, trying to affix it to the dorsal fin of a great white shark.

But most seasons, the state’s leading shark expert will have at least one run-in with an apex predator on dry land.

That was the case on Tuesday, when Skomal was called to Barnstable to help perform a necropsy on a juvenile great white that had washed up along Barnstable’s Sandy Neck Beach in Cape Cod Bay.

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While tagging and tracking live great whites provides needed insight into their habits as they return to the region each summer, the somewhat-rare opportunity to examine a deceased specimen up close can provide even greater understanding.

“A lot of what we know about basic natural history and physiology comes from dead specimens,” said Skomal, senior fisheries scientist with the Division of Marine Fisheries who works closely with the Atlantic White Shark Conservancy to tag and monitor sharks.

He said performing a necropsy gives information about a shark’s reproductive biology, its age and growth, its feeding habits (which is determined through a stomach content analysis), its brain size, and its circulatory system.

“You can’t learn that from a live animal,” he said. “This is a species that is prohibited from retention, which means even scientists like me can’t just go out and kill them. [We] take this as an opportunity to sample as much tissue as we can.”

When one does wash ashore, experts from several organizations are often called in to assist with the dissection. It may seem gruesome to an outsider. But for those who want to know as much as they can about the predators, the methodical process is a crucial opportunity that aids ongoing research.

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“It’s not like I’m celebrating the opportunity because there is a dead shark,” Skomal said. “But at the same time, I’m not going to mourn the death of the animal — I’m going to move on and take a scientific perspective and make use of it.”

Experts will keep everything from the shark’s stomach to its backbone, which can help determine the animal’s age. They will also use its skin, eyes, and other tissues to further their knowledge about the species, as well as practice potential tagging methods.

“Because we are always developing new tag technologies, I keep the dorsal fin,” Skomal said. “I attach tags to it to see how they hold.”

John Chisholm, a shark biologist who works closely with Skomal and the Division of Marine Fisheries, shared a time-lapse video of the necropsy to Twitter on Tuesday.

In the 13-second clip, researchers are shown crowded around the shark — a 7 1/2 foot juvenile male — as they begin to cut into it and slowly dissect it, piece by piece. By the end, all that’s left of the animal is its head.

“Nothing is wasted when scientists do necropsies!” wrote Dr. Vincent Raoult, a fisheries biologist based in Australia, in response to the tweet.

Skomal said it wasn’t immediately clear what killed the shark, but its death wasn’t caused by any obvious external or internal trauma such as an interaction with fishing nets or gear. Tissue samples collected and sent out for pathology could help determine what happened, experts said.

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While there have already been reports and videos of great white sightings along the Cape this summer, the research team has not yet hit the waters to begin tagging and tracking them just yet. (Last season they attached 39 acoustic tags and 10 camera tags to white sharks).

“We wait until we’ve got a predictable number around before we get out and start our work,” Skomal said.

But Tuesday’s necropsy marked what will most likely be a busy shark season.

“We’re starting to ramp up pretty quickly,” he said. “It’s a fun time of year.”


Steve Annear can be reached at steve.annear@globe.com. Follow him on Twitter @steveannear.