|
Eavesdropping on Whales' Mealtime ConversationA graduate student journeys to Norway to investigate how orcas orchestrate their hunt |
|
|
 | |  |
|
| Enlarge ImageResearchers aboard the sailboat Iolaire watch a close group of killer whales in the Tysfjord, in northern Norway. The researchers, including MIT/WHOI graduate student Ari Shapiro, were there to study the whales'unusual behavior when feeding on schools of herring. (Photo by Jesper Jensen) |
|
|  |
|
| Enlarge ImageMIT/WHOI Joint Program student Ari Shapiro prepares a D-tag, a digital recording device that will be attached to a whale. (Photo by Matt Villano) |
|
|  |
|
| Enlarge ImageJesper Jensen prepares to affix the D-tag temporarily and harmlessly to a whale via a long pole and suction cups. (Photo by Michael deRoos) |
|
|  |
|
| Enlarge ImageThe D-tag sticks to a whale with suction cups and records the whale's movements and the sounds the whale makes and hears for a period of hours, then falls off and floats to the surface, to be recovered. (Photo by Sanna Kuningas, University of St. Andrews) |
|
|  |
|
| Enlarge ImageKiller whales, known as orcas, come into the waters of Norwegian Tysfjord in late autumn, following herring schools. (Photo by Sanna Kuningas, University of St. Andrews) |
|
|  |
|
| Enlarge ImageBelow deck on Iolaire, researchers take a break and warm up after hours in the cold, salty air. Geoff Magee (left) served as the boat's skipper. (Photo by Michael deRoos) |
|
|  |
|
| Enlarge ImageTysfjord is home to fishing villages and ecotourism as well as herring, whales, and whale researchers. The Iolaire, owned by prominent orca researcher Tiu Similä of Finland, carried researchers from eight nations during this project. (Photo by Matt Villano) |
|
|
Related Multimedia |
|
|
|
|
|
Related Links |
|
|
Like a knife slicing through denim, the black dorsal fin broke the
surface of the icy water quickly, and then disappeared into the depths.
“Off the port bow,” yelled Ari Shapiro. “Whales!”
From his post on a sailboat roughly 300 meters from the surfacing
creatures, Shapiro, a biological oceanography graduate student,
counted at least six whales approaching in tight formation. He set down
his binoculars and radioed to a trio of colleagues on an inflatable
boat that was following the animals much more closely.
“Mads, please get into position,” he said to Mads Christoffersen, who
was piloting the inflatable boat. “Please get ready to tag.”
Shapiro, a student in the MIT/WHOI Joint Program was referring to
the D-tag, a digital recording device affixed temporarily (and
non-invasively) to whales with suction cups. About the size of a cell
phone, D-tags track the whales’ movements and record the sounds that
whales make and hear in the oceans. Developed earlier this decade by
WHOI engineer Mark Johnson and biologist Peter Tyack, Shapiro’s
advisor, the tags have revolutionized the way scientists study marine
mammals.
Hit and miss
Here, in the expansive Tysfjord of northern Norway, Shapiro was set to
use D-tags in the fall of 2006 to learn more about orca whales. But
first, researchers on the inflatable had to tag some whales.
Christoffersen, the pilot, passed along Shapiro’s instructions to
Jesper Jensen, clad against the cold in a fluorescent Mustang suit, who
staggered against the howling wind and fought his way to the bow of the
boat. Safely situated, Jensen bent down and grabbed a 7-meter (23-foot)
long carbon-fiber pole. At the end of the pole, a D-tag was poised.
As Christoffersen positioned the boat alongside the whales, a huge male
orca surfaced just out of Jensen’s reach. After a few moments, another
whale surfaced—another miss. The whales, probably feeding, were
swimming around furiously in the water surrounding the boat.
Just then, as one orca was readying to descend, Jensen lunged at it and pulled the pole back. The D-tag was gone.
“It wasn’t a clear hit, but it managed to stick,” Jensen yelled into the radio. “We have successfully tagged our first whale.”
The moment the tagged whale dove beneath the surface, a saltwater
switch on the D-tag instructed the device to start collecting data. A
hydrophone on the tag recorded every call and click the whale uttered
or heard. Elsewhere on the D-tag, an accelerometer and magnetometer
began recording the whale’s depth and movements—raw data that
ultimately would enable scientists to calculate every pitch and roll.
For years, fishermen and scientists alike have witnessed orcas swimming
round and round schools of zigzagging herring in Tysfjord to gather
them into a tight, wriggling mass. Then the whales slap their powerful
tails on the corralled fish to stun them before devouring them one by
one.
Researchers have dubbed this behavior “carousel feeding” but have only
begun to understand how the whales manage an attack that clearly
requires coordination, and possibly communication. For Shapiro, D-tags
offer a window into the depths of whale behavior.
“In the short term, I’m hoping to get a better sense of what goes on
when these whales engage in collective feeding,” Shapiro said. “Long
term, we could end up learning something important about the ways in
which whale communication impacts other aspects of their behavior.”
A cold and remote place
Late autumn is a dark time in Tysfjord. The area is one of the most
expansive fjord systems in all of Norway, comprising hundreds of
waterways. Because it sits on the western half of the Scandinavian
Peninsula more than 155 miles north of the Arctic Circle, there are
fewer than six hours of direct sunlight each day.
Most mornings the sun didn’t rise before 8:30 a.m., poking over a
horizon of jagged, snow-capped mountains in a glow of sherbet pink and
orange that reflected on the water below. Norwegians call the largest
of these mountains Stetind
(shtet-in), the “Anvil of the Gods,” because of the way its summit
forms a plateau 1,392 meters (4,567 feet) above sea level. They also
voted the peak their national mountain in 2002.
This setting served as the backdrop for a 30-day window of field
observations on orcas. Over that time, 15 researchers from the United
States, Canada, Denmark, Finland, Greenland, Portugal, Japan, and the
United Kingdom pitched in—eight on Shapiro’s project and seven on
another project coordinated by Patrick Miller, an MIT/WHOI Joint
Program graduate and now a senior research fellow at the Sea Mammal
Research Unit at the University of St. Andrews in Scotland.
Researchers in both groups passed the daytime hours at sea, working on
separate boats. Shapiro’s group used a 39-foot (11.9-meter) sailboat
named the Iolaire. Though the
boat had sails, Capt. Geoff Magee kept it under motor power the entire
time to control its speed near the whales and minimize drift from
frequent gusts off the mountains.
“You never know what the wind’s gonna do around here,” Magee explained
one afternoon on a tour of the fjord system. “Better to be master of
your own power, if you know what I mean.”
The boat was property of Tiu Similä, a Finn who has been one of the
most prominent whale researchers in northern Norway. Similä is
considered the “mother” of orca research in northern Norway, having
brokered relationships among scientists, fishermen, and whale watchers
for the better part of two decades. She was among the first to document
carousel feeding and to compile a photo identification catalog of
whales that frequent the Vestfjord area, which she made available to
Shapiro, Miller, and the rest of the researchers from the beginning.
Perhaps the boat’s most appealing feature was a stove below deck, which
made the cabin a great place to dry off after hours in the cold and
salty air.
Back on shore, in the tiny fishing village of Korsnes, researchers
shared two three-room cabins—modest vacation rentals with working
kitchens. They dubbed one cabin the “eating hut” and used the common
room there to host buffet-style meals for breakfast and dinner.
The other cabin, known as the “science hut,” was where researchers went
to study and tabulate data. When the weather was too lousy to go out on
the water at all, Shapiro and Miller hosted classes there, including
tutorials on how to download and analyze data from D-tags.
The group wasn’t alone out there. Korsnes is a working fishing
community, and occasionally one of the researchers would buy fresh cod
from a fisherman right off his boat. About a 15-minute van ride away,
an ecotourism lodge named the Tysfjord Turistsenter offered free
wireless Internet, which researchers (and at least one intrepid
journalist) used whenever possible.
Perhaps the strangest feature of the area was a lonesome ice cream
truck that drove around at all hours of the day and night, blasting a
catchy tune all the while. Even though the air itself was considerably
below freezing, researchers hailed the truck frequently and enjoyed
every last lick.
They were onto something—even for an ice cream fanatic like me, frozen goodies never tasted so yummy.
Waiting for whales
Shapiro’s research in Tysfjord actually began in November 2005. That
season, Miller, Shapiro, and a team of international collaborators
deployed eight D-tags on eight different whales. The scientists shared
the data. It was a good deal for everyone involved. These first instruments recorded the sounds of all members of a group
of whales, as well as the movements of the tagged individuals within
the group. Five of the tagged animals engaged in carousel feeding.
“We were really enthusiastic about the data that first season,” Shapiro
said. “From what we had, we could see that the orcas engaged in
complex behaviors that are coordinated at the group level and produced
a rich vocal repertoire.”
When fieldwork wrapped up in December of 2005, Shapiro and other
researchers, including Tyack and Andy Solow of the WHOI Marine Policy
Center, began exploring the D-tag data to identify movement and
communication patterns.
By correlating the whales’ sounds and movements, Shapiro is
investigating how the marine mammals may communicate to coordinate
their actions during feeding and other situations. He is also examining
the different kinds of whale calls, their components and their
sequences—in other words, the syntax of their vocalizations.
Heading into November 2006, the plan was to jump in and resume the
study. But there was a problem: no whales. Generally, killer whales
swim into Tysfjord in autumn following schools of herring that return
to the calm and nutrient-rich waters of the fjord to find food. By
November, the herring had not returned, so neither did the whales.
Shapiro and the researchers felt handcuffed for nearly three weeks
before they received word that the animals were sighted in the area;
even then, reports had them 30 miles west, in Vestfjord, where winds
and open water would have made D-tagging challenging at best. One
night, over burritos in the eating hut, Miller put the frustration into
perspective.
“When you study nature, you’re always at her mercy,” he quipped. “You can only do what you can do.”
Indeed, science is like televised poker games: Hours upon hours of
boring hands are edited out; we see only the exciting money hands. In
the world of research, so too might scientists spend 30 days in the
field for three or four good days that comprise the bulk of a published
work.
Eager for data, Miller and his team eventually used their sturdy boat
and hit the open water. Shapiro’s team, on the other hand, waited
things out in Tysfjord, passing time with transmission loss
experiments. Using a speaker designed to broadcast tunes underwater
for synchronized swimming, the crew repeatedly broadcast acoustic
chirps into the water at various depths to gain a better sense of how
sound travels in the area’s waterways. These sounds were recorded by a
D-tag suspended from the inflatable, which was positioned at varying
distances up to 500 meters (545 yards) away. This grunt work
established the audio background onto which whales add their
calls.
The transmission loss experiments were conducted one day after another.
One day, the rain was incessant. Another day, wind seemed to penetrate
even the thickest fleece. Shapiro tried to keep the mood light with
jokes and stories. At one point, he even handed out smiley-face pins as
a token of camaraderie.
“I’m not as much the leader of this project as I am an equal to
everyone else,” he explained. “We’re all in this together. When the
whales finally get here, we’ll celebrate together.”
Tagging time
Finally, the whales arrived. Fishing reports indicated the whales had
been moving in and out of the Tysfjord area for a few days, but
researchers aboard the Iolaire
hadn’t spotted them near Korsnes yet. Miller’s group saw them first.
Shapiro and his team celebrated their successes graciously; now they
wanted some of their own.
On Nov. 9, the whales made their way past Korsnes, darting across the horizon with whooshes as they surfaced to breathe. The water was so choppy that first day that neither the Iolaire nor the inflatable could get within tagging distance. Still, the mere sight of dorsal fins buoyed everyone’s spirits.
“That first day we saw them it was like, ‘Thank God, they’re really
here,’ ” remembered Andy Foote, a doctoral student at the University of
St. Andrews. “Then it hit us—we have got to get those tags on.”
Sea conditions were equally lousy on the morning of Nov. 10, but Shapiro’s team decided they could not wait any longer. The Iolaire
and the inflatable both pushed off from the dock at Korsnes and headed
west into a steady wind. About an hour later, the inflatable motored
up alongside some whales, and Jensen made his heroic lunge.
Back on Iolaire, Shapiro and
his team were doing recordings of their own. From the first day of the
season, the boat had been equipped with a homemade array of 12
hydrophones in a giant tube tailing behind the boat, specially designed
to pick up sounds from the depths.
“I cannot tell you what a relief it was to get the tag on and start
recording,” Shapiro said. “Suddenly, everything we had worked for, all
of our preparations—it all became worthwhile.”
The speedy inflatable followed the tagged whale, but the wind picked up
considerably, making it difficult to spot whales among the whitecaps.
As if the task weren’t difficult enough, the whales decided to pick up
speed and started moving out of the area almost as quickly as they had
come in.
Nevertheless, the boat pursued. After about 90 minutes, the vessel had
lost track of the whales, but Mike deRoos, a Canadian researcher on
the inflatable, picked up a constant string of very-high-frequency
beeps, indicating the tag had come off. An hour later, the inflatable
found the tag floating in the water, full of precious data.
“We sped back to the Iolaire as fast as we possibly could,” deRoos remembered. “It was like we had won the lottery or something.”
Whale tales
Of course, the data remained raw until this winter, when Shapiro
downloaded it and started making sense of what the D-tag recorded.
In the first stage of data processing, Shapiro listened to the hours of
audio data from each tagged animal, denoting when calls, tail slaps and
echolocation clicks (sent out by and reflected back to whales to detect
objects) occurred. Shapiro finished this step in February 2007.
Next, he’ll go back through the record and analyze the calls—squeals,
sirens, and bellows that whales make by moving air around in the
chambers of their heads. Shapiro will attempt to correlate these sounds
with behaviors to discern if orcas are communicating to coordinate
their feeding. Still, comparing and contrasting thousands of calls
won’t be easy. The first step is to run a pitch tracker to extract
fundamental frequencies—that is, digital traces of certain wavelengths
of sound. Shapiro plans to use software developed for telephone speech
by Chao Wang and Stephanie Senneff at the Computer Science and
Artificial Intelligence Lab at MIT, and he has hired undergraduates to
help him parse through the data.
Already, Shapiro said he has found that the whales increase their
calling activity when they increase their movements during carousel
feeding. Ultimately, he hopes to be able to identify certain call types
and cadences and correlate them to certain cooperative feeding
behaviors. Later, he’ll analyze these vocalizations to see whether the
whales flexibly arrange smaller subunits of sound to assemble longer
calls in their vocal repertoire.
Beavers to narwhals to orcas
Whatever he finds, the research itself is a realization of one of
Shapiro’s lifelong goals. During his childhood years, he was always
fascinated with animals and why they did the things they did. Later, as
a high school freshman in the suburbs of Cleveland, Ohio, Shapiro once
began a presentation about marine biology with a photograph of a killer
whale.
“I started rattling off all of these facts about killer whales,” he
remembered. “Then I stopped and said, ‘I don’t want to grow up and
become a killer whale; I want to study them.’ ”
In high school, Shapiro drew
inspiration from his AP Biology teacher, Mrs. Nora Doerder, who animated
his interests in the life sciences.
By the time Shapiro entered Boston College in 1997, he was convinced
he’d focus on molecular biology. In his second year, he met Donald
Griffin, a biology professor emeritus who had been Tyack’s graduate
student advisor at Rockefeller University. Griffin invited Shapiro to
join him on a project studying a small group of Canadian beavers
outside Concord, Mass. Shapiro jumped at the chance.
The next summer, he was accepted into the WHOI Summer Student
Fellowship Program and worked in Tyack’s lab under the direction of
Miller, who was then a graduate student. After receiving a bachelor’s
degree in biology, Shapiro spent a year at the University of St.
Andrews, where he obtained a master’s degree in animal behavior for
work that involved training gray seal pups.
“It was in graduate school that I really got hooked on the idea of
studying marine mammals full time,” said Shapiro, who participated in
a couple of research projects during his time abroad. “I came back and
thought, ‘I can do this. I actually can do it.’ ”
He did do it. But first, Shapiro spent a year in New York participating
in a program called Avodah: The Jewish Service Corps. During his stint
there, Shapiro worked as a legal advocate representing clients on
welfare who were homeless or precariously housed. Looking back, he
recalls the time as one of the most formative of his life and says it
was valuable to “take a year off from schooling and focus on others and
on issues of social justice and equity.”
The following year Shapiro joined the MIT/WHOI Joint Program. His first
project involved communication among narwhals, toothed whales that are
famous for their unicorn-like tusks. That research was published in the
September 2006 issue of the Journal of the Acoustical Society of America.
The opportunity to study the killer whales of Tysfjord finally
presented itself in early 2005. Representatives of the Norwegian navy
contacted Tyack looking for guidance with experiments that would expose
killer whales to controlled amounts of sonar activity. In exchange for
advice and associated involvement, Tyack paved the way for Shapiro to
research the same whales.
“We had a unique opportunity to go in there and study whales in a
unique environment,” said Tyack. “Ari took that responsibility
seriously and has made the most of it.”
What's next
While the Norwegian navy did not run sonar tests during the 2005
season, it did conduct them in 2006. Local fishermen and ecotourism
operators were quick to blame the tests for spooking the herring and
keeping whale sightings low. During my brief visit to Tysfjord, the
locals met with researchers and navy officials at the Tysfjord
Turistsenter in a heated discussion about the future.
While Miller and other scientists remained patient during the two-hour
talk, many local boat captains and naturalists became animated when
expressing their concerns to the navy about the long-term prospects of
the area’s nascent whale-watching business with no whales.
“If you drive the fish out and the whales don’t come back, then what
will we do?” asked one boat operator. “For you, it is an exercise. For
us, it is a livelihood.”
Nobody knows for sure yet what the impacts of future testing might be on the whales or on whale research in Tysfjord.
“The great thing about marine biology is that there are always new
questions,” said Shapiro, who expects to complete his Ph.D. in 2008.
“I’d like to continue to study in Norway, but if I can’t find my
answers here, I’ll find them somewhere else. The answers are
everywhere. That’s what makes this fun.”
—Matt Villano
This project was funded by the Ocean
Life Institute at WHOI, the National Geographic Society, the MIT
Undergraduate Research Opportunities Program Office, and the National
Defense Science and Engineering Graduate Fellowship.
Posted: August 9, 2007 [top] |
|
