Shark Washes Up On Sagamore Beach
A stranded shark washed up on Sagamore Beach earlier this week. The shark was still alive when it was spotted on Monday afternoon, January 9, but died overnight and was recovered by experts for sampling on Tuesday.
The shark was spotted by a family walking their dogs, according to a report by Boston 25 News. The family reported the sighting, and that report made its way to John Chisholm, an adjunct scientist affiliated with the New England Aquarium’s Anderson Cabot Center For Ocean Life’s Sharks, Fisheries Science and Emerging Technologies (FSET) Program.
Mr. Chisholm tweeted about the stranding on Tuesday after he was alerted by the New England Coastal Wildlife Alliance. In an interview with the Enterprise, Mr. Chisholm said he spent 28 years with the state’s Division of Marine Fisheries, so he has a vast network of contacts spanning numerous organizations that still keep him in the loop on various sightings and strandings.
“If it’s a shark, it usually ends up getting reported through the grapevine back to me,” he said. “I help everybody that is interested in sharks.”
Mr. Chisholm made his way to Sagamore Beach on Monday to see the shark, which was still alive and swimming when he arrived. He tweeted a video of the shark, a female porbeagle, swimming in shallow waters the following day, writing that a “Good Samaritan moved it into deeper water but clearly it was not well.” Mr. Chisholm said the shark was about six feet long and very thin, and died a few hours later.
“The tide went out and left it high and dry,” he said, adding that he and other experts then made a plan to recover the shark on Tuesday morning for a necropsy. Sharks strand for different reasons, he explained, noting this particular shark did not have any signs of obvious trauma that would have caused its death.
Michelle Passerotti, a fish biologist with the NOAA Fisheries Apex Predator Program out of Narragansett, Rhode Island, this week conducted the necropsy on the porbeagle with a team of scientists, including Mr. Chisholm.
“We try to collect these stranded sharks anytime they wash up,” Ms. Passerotti said, “just because if it’s already dead, it’s a great opportunity for us to collect samples we normally wouldn’t be able to obtain from a live shark.”
“Everything gets used so the shark, as sad as it is that it died, is going to get studied and a lot of different researchers are going to have access to it,” Mr. Chisholm said. “It is ultimately going to benefit science.”
The Apex Predator Program, which runs the oldest shark tagging program in the world, sees a variety of sharks, but Ms. Passerotti said porbeagle sharks are common in Massachusetts at this time of year. Porbeagles are cold water sharks and belong to the same family as the great white shark and the Mako shark. Mr. Chisholm said that while most people have never heard of the porbeagle shark, it’s not rare to see them around here, especially because they stay in the cool waters of this area year-round.
“It’s rare for it to wash up on the beach like that,” Mr. Chisholm said, “but it’s a shark that I like to say, if Massachusetts had a state shark, it would be the porbeagle shark.”
The team conducting the necropsy collected a number of samples from the shark, including skin cells and tissue from the muscles, brain, heart and liver. The samples were sent out for pathology, Ms. Passerotti said, which will help identify any pathogens or “anything strange that might’ve been an underlying cause for the shark to wash up.”
“We try to take everything that we can so that nothing goes to waste,” she said.
Team members also took samples that will help depict the shark’s life history. Vertebrae samples can indicate age, she explained, and analysis of the stomach can delineate food habits and diet. Reproduction is also studied, along with more niche areas, such as eyeball sampling to study eye lenses. One student, from the Harvard School of Comparative Zoology, took samples of the shark’s dermal denticles, which are the microscopic scales that cover its skin.
Pathology results available in six to eight weeks, may lead to an understanding about what caused the shark to strand.
Mr. Chisholm asks that, if anyone does come across a stranded shark, they reach out to him through his Twitter or Facebook, @MASharks.