The pandemic offered a unique chance for scientists to sample stress levels in whales while there was minimal tourism activity in Juneau’s waters. Federal biologists took advantage and took samples in 2020 and 2021.
In 2022, tourism was almost back to pre-pandemic levels, so samples taken this year will show the difference in the whale’s stress levels when there are and aren’t boats in the water all summer.
Suzie Teerlink studies whales and coordinates whale watching practices with NOAA’s Whale SENSE program in Juneau.
For the study this year, researchers collected samples of the stress hormone cortisol from whales in Juneau waters. Teerlink said they take those samples from blubber, which stores the hormone longer than blood does.
“In blubber, it takes weeks and months to accumulate,” she said. “And so we’re getting more of a cumulative average of what their physiological stress environment has been in the weeks and months prior.”
That also makes sure that the sample doesn’t reflect the whale getting temporarily stressed out by the dart that takes the sample. Teerlink said the whales often show that they feel it a little bit, sort of like a bee sting.
“Generally speaking, after we take a biopsy sample, we do monitor whales for some period of time,” she said. “And by and large, they go back to what they were doing before, so we think that it’s a pretty small impact.”
A 2019 study used instruments posted on land that observed the whales without influencing their behavior. The instruments record respiratory rates, dive patterns and speeds of whales. This tracked the more immediate behavior differences, minute by minute.
“And what they found is that, especially as the number of boats increased, they did see faster swimming speeds, faster rates of respiration, longer downtimes, and changes in direction,” she said.
That study was led by Heidi Pearson with the University of Alaska Southeast. Pearson is also the lead investigator for this year’s stress study.
Pearson said they biopsied 24 whales in total and will use photographic data to track which whales are coming and going.
“We’re also trying to determine if there’s a change in residency, or how long whales are here each year,” Pearson said. “And also how many whales are here each year, because we predict that there might be changes in how many whales are here, or how long they stay, depending on the vessel traffic.”
Teerlink, Pearson and their research group are expecting results from this latest round of data next spring, which will be just in time to help better inform whale watching practices in Juneau for next season.
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