Chasing down and wrangling injured gray seals as they scramble down the beach toward the water’s edge may soon no longer be necessary for researchers and volunteers who want to disentangle the animals from fishing nets.

Officials from the International Fund for Animal Welfare, a non-profit organization, announced this month that a rescue team successfully used a sedation dart with an acoustic tag during a recent mission in Chatham. It marked the first time, according to the group, that the new technique has been used on a pinniped on the East Coast.

“I have devoted a lot of my professional life to disentangling marine animals – primarily large whales and sea turtles, but many seals, too,” said Brian Sharp, IFAW’s manager of marine mammal rescue and research, in a blog post about the recent expedition. “And I see this as a major milestone for our work.”


Sharp and a team of biologists and veterinarians from The Marine Mammal Center, the Center for Coastal Studies in Provincetown, National Marine Life Center, and National Oceanic and Atmospheric Administration set out July 27 on three small boats in Chatham to test the device. A video of the mission was posted online last week.

Typically, researchers, using binoculars, will spot a seal on the beach with netting wrapped around its neck. They will then slowly approach the animal, net at the ready, in an effort to capture it and remove the constricting material. This can be difficult, as seals often flee — or “flush” — into the ocean en masse, making a daring escape.

With the dart system, rescuers can cautiously approach a large grouping of gray seals, pinpoint an injured individual, and fire the dart into its body. The dart then releases a drug that sedates the animal. To avoid the risk of the seal drowning once it’s passed out, the dart contains an acoustic transmitter. As the seal tries to swim away after being shot, researchers can follow and track it based on “pings” emitted from the device, to ensure they can carry out their mission.


In the video showing the process, posted to IFAW’s website, the rescue crew can be seen approaching a pile of gray seals lounging on a sandbar near North Beach. As they slowly ease their boat toward the animals, they identify a small female seal weighing about 220 pounds with wiry material cutting into its neck. With precision, a researcher fires the dart, making a direct hit to the animal’s shoulder.

Sharp described it as the “perfect shot.”

The team later catches up with the sedated seal on the opposite side of the sandbar, captures it in a net, brings it to shore, and goes to work removing the monofilament fishing net. After tagging the seal so they can monitor its recovery, the team sets it free.

“This is a significant step forward in responding to entangled seals locally,” Sharp wrote. “The information we gather on drug efficacy, capture tools, and techniques can also help other entangled animals around the US and in other parts of the world.”

Officials from IFAW said they planned to try the technique again sometime in September or October.

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