A species tagged for survival
Electronic marking may help scientists in quest to protect whales
The inflatable boat rocked in the gentle waves 16 miles off Scituate as Cornell University engineering student Erik Dawe leaned forward, concentrating intently on a patch of bubbles in the water. He knew that a 40-ton humpback whale he and his colleagues had been pursuing for more than an hour would soon surface. He steadied himself.
Suddenly, the massive mammal broke the water not 30 feet away. Nervous but exhilarated, Dawe quickly lowered a long pole attached to the boat's bow and slapped a small electronic tag on the whale's glistening back.
"Tag on, tag on," his colleague Cara Pekarcik of the Whale Center of New England chirped into the boat's radio to cheers and sighs of relief from the researchers watching aboard a nearby vessel.
Chasing a beast the size of a small house might seem like a bizarre pastime for scientists, but to the team of whale experts who traveled to Stellwagen Bank National Marine Sanctuary from around the country this week, tagging whales promises to unlock the mysteries of their underwater behavior. The electronic tags allow scientists to monitor both movements and sound, information they hope will guide them in developing better ways to protect the humpbacks and other endangered whales from being struck by ships or becoming tangled in fishing lines or nets.
Many whale species are threatened as they increasingly share their habitats with massive tankers, industrial fishing nets, and recreational boats. In addition, a growing body of research indicates that hu man-caused noises, from ship engines to explosions, can interfere with their communication. Humpback whales hit the endangered species list in 1970 after years of commercial whaling, though scientists report that their numbers have bounced back in some areas. The population of North Atlantic right whales, which also inhabit the sanctuary, has dwindled to an estimated 350 animals overall.
Electronic tagging is the latest technology scientists are using to study a creature they cannot easily observe or follow. The tag, about the size of a paperback book and containing sensors and a hard drive, measures the direction of whales' movements and records their sounds, allowing researchers to see and listen as whales feed and interact underwater. It attaches painlessly to the whales with suction cups much like those on the bottom of a shower mat, then releases automatically several hours later and floats to the surface, where scientists retrieve it.
With the tag, "we're almost like terrestrial biologists," said David Wiley, research coordinator at the sanctuary and leader of the multiyear tagging project. "Terrestrial biologists can go and watch a lion or a gazelle, and see the trees and other animals around them. We can't do that, but now with this technology we can come close."
Humpbacks, which some scientists call drama queens because of their close approach to boats and flamboyant tail-slapping, migrate to Stellwagen Bank from the Caribbean in spring and summer to feed on fatty sand eels.
With a permit from the National Marine Fisheries Service, researchers motored out to see the whales in the misty dawn Wednesday. When they spotted the telltale sprays of two whales a quarter of a mile away, teams of scientists jumped into small rubber crafts and zoomed after them. They circled the whales carefully, waiting for the right moment.
Tagging can be tricky, even perilous. Researchers fear that whales could leap from the water and land on a boat. And they also must take care not to startle the creatures when they tag them, which could change their normal behavior.
"You don't want to make a lot of boat noise and whack them because that's not respectful," said Dawe. "You can't screw up because you spend two hours approaching an animal and it's about one moment. That moment makes or breaks the day."
After Dawe finally succeeded in tagging the whale, behaviorists from the Whale Center compared distinctive markings on the underside of its tail to a catalog of 2,000 individual whales the center has tracked over the past four decades. They identified it as Ampersand, an 11-year-old behemoth whose sex is undetermined.
Ampersand took the scientists on a 5-mile journey as it frolicked and fed with other whales. While Whale Center staff followed on the surface, ecologists from Duke University used sonar to measure the density of fish schools in the water around the whale to analyze its feeding behavior. Mapping specialists from the University of New Hampshire will enter that information, along with sound and movement recorded by the tags, into a computer program that will create a three-dimensional movie of Ampersand's activities.
The researchers are focusing on how social interaction among whales in the same group affects their ability to avoid dangers. Young whales, for example, collide with ships more often than adults. So the scientists tagged a mother-and-calf pair earlier in the week and will examine whether the calf followed its mother as she dove deep to avoid oncoming boats.
"If they're not following the mom down and just playing on the surface when a ship's coming, it's like playing in the street," said Duke postdoctoral researcher Ari Friedlaender.
Last year the scientists found that whales rolled back and forth on the sea bottom while feeding, putting them in danger of being caught in the lines lobstermen were using to connect their traps, which could float a few feet above the ocean floor. The discovery helped convince the Massachusetts Department of Marine Fisheries to require the lobster industry to switch to lines flush against the bottom.
On Wednesday, researchers failed to meet their goal of tagging three animals. But the scientists, hardy souls who wear T-shirts with pictures of whales, still returned to shore invigorated.
"Whales have been a big part of so many people's lives, but we still don't know much about how they live," said Friedlaender, who joined the Cousteau Society when he was 4 and recently spent a frigid winter tagging killer whales in Norway. "What pushes me forward is trying to learn things about these animals that will get other people jazzed about protecting them and the entire ocean." 