Study: Oregon gray whales are shrinking in size


For four summers in a row, Oregon State University faculty research assistant Todd Chandler could be found on a small boat off the coast of Oregon piloting a drone over the unsuspecting backs of gray whales piercing the surface of the ocean.

A study published on Friday that used images from Chandler’s drone, as well as almost 1,500 others taken by additional researchers, reached a surprising conclusion — the average size of Oregon’s whales is getting smaller.

The study, co-authored by researchers at Oregon State University, found that among the community of whales that spend their summers feeding in the waters off the coast of Newport, Depoe Bay and Lincoln City, whales born in 2020 are expected to be 13% shorter in length as adults than whales born before the year 2000.

Researchers collected data from late May to mid-October for seven years beginning in 2016. According to the study’s authors, the researchers during that time observed 130 individual whales, which they were able to identify by their unique colorations and scars.

Leigh Torres, an associate professor at OSU and one of the study’s seven authors, said the findings could be a dire warning about the health of Oregon’s marine ecosystem. She said that the whales’ reduced size is likely due to climate change, which has harmed the flow of nutrients that contribute to the whales’ diet. She added that the whales are a “sentinel” species that reflects the health of their environment.

“If the whales aren’t finding enough food, then probably those fish species aren’t either,” she said. “Their health represents the health of that whole reef and ecosystem.”

If the whales are getting smaller due to a lack of nutrition, it could spell problems for their ability to reproduce, Torres said. If female whales aren’t able to get enough food, it will make it harder for them to support their calves in the womb, let alone care for them once they are born.

Torres said that size changes in an animal population are often a “warning sign” before a population decline, and she said that researchers saw fewer gray whale calves as they performed their research.

Humans getting too close to whales is another possible factor preventing them from getting food, she said. Torres said that when boats get within 100 feet of a gray whale it will cause them to stop feeding.

“People often think, ‘Oh, it’s just one time that I wanna have a good look,’” she said. “You have to multiply that by 20 or 30 boats per day, and then every day of the summer and then it becomes, you know, a big harassment for the animals.”

She said that the use of drones in the study helped researchers avoid disturbing the whales.

“Once the drone technology came out there was just this sort of epiphany moment in my head thinking, ‘OK, this is a fairly cheap piece of equipment that can give us this great view of the animals,” she said. “We can watch them for a while from above and again not disturb them.”

Chandler, who said he had prior experience with drones, served as one of the research project’s first drone pilots. He said that the researchers took off-the-shelf drones such as those used by hobbyists and modified them so that they could judge their flying altitude using GPS and specialized lasers. Those modifications, Torres said, allowed the researchers to calculate the scale of the photos they took and accurately measure the whales.

Torres said she hopes the research resonates with people in the state.

“They’re Oregonians like us,” she said. “So if they’re struggling, we should pay attention and try to help them just like we would help other Oregonians.”

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