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  • Richard Conniff writes about behavior, in humans and other animals, on two, four, six, and eight legs, plus the occasional slither.

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Beyond Butt Dialing: Blubber Dialing–Seals Part 4

Posted by Richard Conniff on August 18, 2014

 

The capture

The capture

One morning back in Chatham harbor, the fishermen watch out of the corners of their eyes as scientists and federal agencies get ready to head out on a seal research mission. It takes two hours of loading equipment, working out a plan, and explaining it to assembled reporters before the party even gets off the dock. It’s a flotilla of six little boats in a line and—to general snickering among the fishermen–they never even make it out of the harbor.

They don’t need to: There are plenty of seals to work with just 15 minutes from the dock. A little before 9 a.m., the two lead boats drop down a little below an exposed sandbar, where a hundred or so seals have hauled out. Then the boats turn and ease back up, on either side of the sandbar, with a tangle net bellying out in the water between them. As the seals scatter, other members of the team jump onto the sandbar and start hauling in the net. In short order, they have four seals ashore and start the careful business of untangling. “Nails free?” someone yells, and “I’ve got a flipper here!” Three seals quickly get released again, rejoining a vast herd now bottling nearby.

The fourth, a female, gets

The weigh-in.

The weigh-in.

shifted into a carrying net and transported by boat to a broader stretch of sand where, at 9:38, the scientists inject a sedative, weigh her in at 337 pounds, and gather around her in a sort of outpatient surgical scrum. At the head, someone extracts a tooth for aging, and at the tail someone else inserts what’s supposed to be a rectal thermometer but looks more like a colonoscopy tube as it threads endlessly inward. A guy with a computer rigged from a shoulder harness, like a beer tray at the ballpark, steps in to take a quick ultrasound image for blubber depth, then deftly steps aside to give other scientists room to take blood, skin, blubber, microbial swabs and other samples. “Got a whisker,” the guy at the head calls out. “Who needs a whisker? O.k., we’re up to 16 minutes.”

Transmitter in place

Transmitter in place

Someone is now mixing tubes of five-minute epoxy and slathering it onto the mesh fabric backing of a $5000 electronic device about the size of a point-and-shoot camera. Glued to the back of the seal’s skull, it will record her location, depth, ocean temperature, and other indicators for up to 9 months. Every time she comes ashore long enough to dry off, it will trigger the device to place a cellphone call and transfer the latest data, until finally the device drops off when she molts. The team will place similar devices on a total of nine seals over the next few days—and then analyze the data over the coming year. In a pilot test of the technology last year, a juvenile gray seal named Bronx swam 25,000 miles in the first five months, including a two-week trip out to the Georges Bank, with dives down 900 feet.

“So we can start to understand the ecology of these animals,” says Dave Johnston, a marine conservation biologist at Duke University. “Where do these animals go? How often do they travel? How many times a day do they dive and how deep? How does that overlap with ocean topography? How does it overlap with where people go?” A graduate student will work to see how seals interact with the fishing community. “Right now, we don’t know much and when people don’t know much, they’re worried and fearful. When there’s more information, we can move to understanding.”

“She’s starting to come up a little bit, guys,” one of the scientists calls out. A tag on the right and left flippers now identify her as seal 141. Someone calls out a checklist: “We got hair, we got skin, we got anal, we got whiskers.” Then everyone suddenly backs away as the waking seal lifts her baffled head.   She studies the two-legged beasts all around her in puzzlement, then finally recovers enough at 10:40 to drag herself back to water and rejoin her herd.

 

Time to run

Time to run

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