By Cameron Kittle
Almost like a primitive video game, the three-dimensional software TrackPlot shows a bulbous, gray whale figure traveling slowly along a line with red and blue spikes that depict the strength of its fin strokes.
Yellow-shaded areas show when it rolls its body more than 40 degrees in any direction, such as when the creature spirals up to the surface as part of the "bubble-feeding" process, and the dimensions of the track show every rise and fall of the whale's 40- to 50-foot-long body.
Mason Weinrich, longtime executive director of the Whale Center of New England, has been using this new software, developed by ocean scientists and engineers at the University of New Hampshire, to track a population of about 700 whales off the region's shores and study their underwater behavior.
It starts with digital tags, made and developed by scientists at Woods Hole Oceanographic Institution, that are programmed and placed on the whales for a maximum period of 24 hours.
These "D-Tags," as they're called, are about 12 inches long, 6 to 8 inches wide, and take 50 readings per second of the whale's depth, orientation, heading, and any sounds the animal makes or hears. It's almost impossible to observe the whales underwater without the D-Tags, since the water is so murky around the North Shore and the whales often swim away when humans or submarines attempt to interact with them.
But with the tracking system and the D-Tags, Weinrich can see everything they do.
"It's like that song by the Police: 'Every breath you take, every move you make, I'll be watching you,'" he said. "We know a lot about these animals, so we can take this data and put it in context."
The study is part of an annual two-week research effort, from July 18 to Aug. 1, that the Whale Center of New England, based at Harbor Loop in Gloucester, has helped with each of the past five years. The project is being carried out in collaboration with Woods Hole, UNH, the Stellwagen Bank National Marine Sanctuary, Pennsylvania State University, and Duke University in Durham, N.C.. While it has previously not had an official name, this year it has been called the Whale Investigations in Local Ecosystems Year 2009 (WILEY 2009) in honor of Dr. David Wiley, an important member of the project who couldn't be involved this year due to health issues.
The National Oceanic and Atmospheric Administration, also a partner in the study, provides the Nancy Foster, a 210-foot vessel where the scientists live and work.
The main purpose of the research is to understand the underwater behavior of whales, Weinrich said, including their feeding strategies and practices, the relationships within their society and how they interact with other ecosystems.
Weinrich said the information is very useful because, while he and other scientists can study the whales at the surface all year long, it's important to know what whales do underwater, where they spend 90 percent of their time.
Weinrich and his team — including Assistant Director Heidi Pearson, Operations Coordinator Tracey Bowen, naturalists Laura Ganley, Kelly Slivka and Kelly Keen, and database manager Jenn Tackaberry — have already come up with some qualitative observations after the first week of research as part of the WILEY project.
Weinrich said the group has found that humpbacks may be using sonar to attack prey — a previously unknown observation — and that the difference between a whale's day and night activity is as different as, well, day and night.
Weinrich has also found that whales in pairs or groups do not always feed cooperatively, as many believe. Instead, one whale will appear to take advantage of the other by lagging behind and then accelerating past its partner to swallow the prey, almost like the drafting technique that runners use to conserve energy.
Humpback whales are considered an endangered species, and 75 percent of the whales in this area have scarring from collisions with ships or entanglements with fishing gear, Weinrich said. So, the information is also valuable because it can be used to find out what people can do to modify fishing, boating and shipping practices and lower the risk of whale injuries and deaths.
Dr. Ari Friedlander, a research scientist at Duke University, has been working with Weinrich and Dr. Wiley for the past five years as a part of this annual project, and his research focuses on the foraging and feeding behavior of whales.
The data that's been collected through the TrackPlot software is extremely helpful, Friedlander said.
"What the tags are able to demonstrate is how much time the whales spend in each part of the water column, whether it's in the first 8 meters or at the bottom," he said. "We can tell when they feed by their orientation and acceleration in the water, and there's been significant changes in terms of the types of prey that's available to them. There's sand lance, krill and herring, and the whales have different behaviors to take advantage of their prey in each different form."
One reason the Whale Center of New England is especially important as a partner in the study is because the longtime staff members, like Weinrich, are on a first-name basis with the whales after identifying the animals for years by the distinct markings on their tails.
"Working with Mason is great because he knows all the whales individually," Friedlander said.
The Whale Center of New England works on a number of humpback whales throughout the year to understand more about them, but these two weeks are essential to learn more about their activity underwater.
"What you see at the surface is bubbles," Weinrich said of the whale's bubble-feeding process. "What you don't see is the triple spiral the whale did to make those bubbles."
Cameron Kittle can be reached at gt_reporter@gloucestertimes.com
