Marine mammal researcher Bree Witteveen has had a busy summer.
In the past few months, researchers Witteveen, Kate Wynne and Lei Guo have been tracking and documenting the spread of Kodiak’s whales.
The Gulf Apex Predator project started in 1999, and since then has studied the foraging ecology of fin whales and humpback whales around Kodiak Island.
“We look at what they’re eating, how their diet overlaps with each other, and more importantly how their diets overlap with other users of the ecosystem like sea lions, seals and fishermen,” Witteveen said.
The marine advisory program researchers study the whale population as a whole to estimate the number of whales that are feeding in the Kodiak Island area.
Witteveen estimates how many whales are in the region by identifying them with pictures. This summer she took pictures of 45 fin whales and 200 humpback whales.
“Each species of whale has a feature on it that is unique to individual animals, so we can do photo identification,” Whitteveen said.
Around 800 humpback whales and 300 fin whales are in the Kodiak Island area.
During the cruises, Witteveen also gathered biopsy samples by shooting an air rifle at the whales to collect a plug of skin and blubber. The marine advisory program has permits to get close to the whales and to shoot them with the dart.
“The dart hits and bounces off and we scoop it up,” she said. “It’s the equivalent of us getting a pinprick.”
Once they’ve got the biopsy, the researchers take it into the lab.
“It essentially tells us what they’re eating,” Witteveen said. “Where they’re feeding in the food chain, and if they’re feeding near shore or off shore.”
The research ultimately determines what effect the whales have on the local ecosystem. The whales’ consumption of fish species may indirectly affect fisheries in the region or the recovery of Steller sea lions.
“Whales in general were commercially harvested until the ’60s,” Witteveen said. “Population numbers were almost nonexistent, and now there is an incredible recovery. To think our ecosystem can handle that significant drop and then increase without seeing any sort of fluctuations in other populations that use the same area is not realistic.”
Witteveen has also been working on a study of whale deterrents; it started in 2011.
She held a meeting with fishermen to learn what techniques they use when whales approach their boats or nets. Some common techniques included shooting bottle rockets, banging something on their boat or tightening their nets.
“What the study is doing is trying to look at behavior of whales around fishing boats and fishing sites,” she said. “Whales get in set nets and seine gear. We’re trying to approach this from the point of view of avoiding it happening altogether.”
The study involves tagging whales, then tracking the tagged whales as they encounter different deterrents. Due to bad weather, Witteveen’s team was unable to tag any whales this summer, but the study is expected to continue next summer.
Witteveen will give a public talk about her whale research at the Baranov Museum on Wednesday.
If you go:
“Thar She Blows!”
Sept. 26 at 7 p.m.