Turtles caught in Kalamazoo River oil spill living longer after rehabilitation

Long-term survival of turtles covered in oil during the 2010 Kalamazoo River pipeline rupture disaster was proven to be improved by efforts to clean and rehabilitate them.

Recently published scientific research showed how time spent by volunteers scrubbing oil from wild turtles with toothbrushes and cotton swabs, using little dabs of Dawn dish soap, increased the survival rates of those slicked with low-grade crude in the Kalamazoo River oil spill catastrophe. Northern map turtles that spent the winter in rehabilitation survived even longer, the study found.

That means turtles will survive longer after disastrous oil spills in freshwater systems if captured and cared for by wildlife responders. About 8% can be expected to immediately die, statistics showed.

Biologist Josh Otten was among those who responded to the Marshall, Michigan, area 12 years ago when 843,000 gallons of bitumen oil flowed into a tributary creek to the Kalamazoo River in what was determined among the largest inland oil spills in U.S. history. He spent 14 months paddling the waterway and collecting turtles covered in oil.

The turtles went to a rehab area for treatment before eventually being released back into their native ecosystem.

“We were bringing in almost 100 turtles a day at one point, and some of them were just completely covered with oil. Some of them had a little bit of oil, but then you had to figure out how to keep them all because they need proper heat, water, all that stuff,” he said.

“And then at the same time, we had tons of people just going through and cleaning the oil off the animals and you didn’t want to stress them out. They could only do it like at an hour at a time.”

Otten also collected data during the extensive wildlife rescue operation. Lots and lots of data.

“When I left the project at the end of 2011, I had all these questions in my mind. We did all this work, but what happens after the fact? It’s one thing to interact with these turtles for a week at a time … but you weren’t really sure what the oil does to them long term or to the environment they came from long term,” Otten said.

Seven years later, the researcher saw an advertisement for a doctoral program at the University of Toledo to study the effects of the oil spill on turtles in the Kalamazoo River system.

“I was like, ‘Hey, I know the turtles in that river probably better than anybody. I think I’d be a perfect fit,’” Otten said.

The research was funded by the U.S. Fish and Wildlife Service through civil penalty money paid by oil and gas transportation giant Enbridge, which owned the ruptured pipeline that leaked bitumen oil into the waterway.

In 2018, Otten started paddling the river and collecting turtles again, which he continued for another three years. He recaptured northern map turtles previously caught, some multiple times before. Each was tagged with an electronic microchip like the sort used for pet dogs and cats.

Research showed turtles rehabilitated in captivity through the winter months following the oil spill disaster had the best survival rate among all those studied. Also, those cleaned and rehabilitated for shorter durations survived better than those found without any oil that were marked and immediately released back into the befouled waters, Otten said.

The scientist said this proves time and money spent to rescue and rehabilitate turtles after catastrophic oil spills is worth the effort to protect biodiversity in freshwater streams and rivers.

He said for animals like turtles, which can live 60 or 70 years, this remains important because of the time needed to regenerate the population; turtles reach sexual maturity in 14 years, while other animals often harmed in oil spills, such as birds and frogs, can reproduce every year or two.

“But turtles, if they take a little bit of a hit, it takes a while for that population to start to rebound,” Otten said.

Many adults, juveniles, and hatchlings were captured and recaptured between 2018 and 2021, which the scientist said suggests population growth since the oil spill disaster.

Further research into specific wildlife rehabilitation strategies, emergency spill responses, and habitat restoration protocols remains necessary to develop best practices to ensure the survival of long-lived species, such as turtles, after large-scale oil spills, Otten argues.

“You feel good when you clean that oil off, but you’re hoping that they’re going to go back out there and live their turtle life.”

Related articles:

Six years after historic oil spill, feds close the book on Enbridge catastrophe

NTSB report: Enbridge, federal regulators missed numerous opportunities to prevent or lessen impact of Kalamazoo River oil spill

Kalamazoo river restoration projects to use $27M in PCB settlements