This story was reported in partnership with NPR’s “Here to Help” series about volunteers who give back to their communities.
On a cloudy morning in early April, Ron Eby and a couple other volunteers from the Elkhorn Slough National Estuarine Research Reserve (ESNERR) head out into the calm, blue waters of Elkhorn Slough in a very quiet electric boat.
Immediately, they’re surrounded by wildlife—a pile of barking sea lions, an eared grebe, harbor seals.
Then, after just a few minutes, the main attraction.
“There's the otter right in front of us,” Eby says as he slows the boat.
A furry brown southern sea otter splashes around in the estuary.
Eby spent 20 years in the Navy before he retired from his role as a commander. But after a while, he got bored. So he signed up for a new covert mission.
“To go out there in the middle of the night, park, turn the lights off, kind of hide,” Eby said.
And look for otters. Not enemy warships—but threatened sea otters.
All that surveillance led to new understandings about the marine mammals once hunted nearly to extinction for their uniquely warm coats.
Twenty years ago, scientists thought these otters typically lived in the ocean. But Eby and his friend Robert Scoles, a retired sheriff’s deputy, weren't so sure.
“We would see things that didn't fit what they were saying,” Eby said. Like otter footprints and scat on the Elkhorn Slough shore.
And that made them curious. They’d just started volunteering at the estuary, and they wondered—if the otters mostly just visited, why were there so many footprints?
“After all my time in the Navy and Robert's time as a sheriff, you kind of like to check things out,” Eby said.
So they did. That's how they ended up on their covert nighttime mission.
For two years, twice a month, Eby and Scoles staked out the otters overnight. No one had ever monitored the animals like this.
The pair discovered that many of the otters scientists thought were visiting the estuary were actually residents. And the otters did something called "hauling out"—when they scoot out of the water and onto land as a way to rest and warm up.
“And we found that otters here in Elkhorn Slough were healthier by far than all the otters along the coast,” Eby said, because they don't have to worry about predators, and food is abundant. “So that really was a breakthrough.”
All the monitoring by Eby and Scoles changed scientists’ understanding of otters. For example, they realized that the estuary—which is quiet and undeveloped, unlike a lot of California’s coastline—gave the otters more opportunities to haul out.
This discovery led to other research showing that not only do otters thrive in estuaries, but they’re part of an important food chain that helps the rest of the ecosystem thrive, too.
Otters eat crabs, which helps keep their population down so they don’t gobble up all the little snails and sea slugs that keep eelgrass clean and healthy.
“If you get too many crabs, the eelgrass gets covered with algae and it dies,” Eby said.
Which is bad, because eelgrass is full of climate benefits. Among other things, it stores carbon dioxide and helps prevent erosion.
As the boat heads back toward the harbor, Eby points to an example of his body of work—a furry brown blob on the shore.
“That's an otter hauled out on the marsh,” he says.
Back on land, ESNERR Research Coordinator Kerstin Wasson is waiting.
“I've worked with so many amazing volunteers, but I've never met one quite like Ron Eby,” she says.
Wasson credits Eby with starting the Reserve Otter Monitoring Project, which now has 30 volunteers.
“He is such a generous man and loves to mentor the other volunteers and infect them with his enthusiasm for the sea otters,” she said. “So he's really giving that gift to the other volunteers as well as to our science of studying the sea otters.”
Eby, who’s now 78-years-old, says every time he goes out to look for otters he still learns something new.
“ That's what makes it enthralling,” he said, “and something you would just wanna keep doing forever.”
