The Elwha River flows from the heart of the Olympic Mountains north to the Strait of Juan de Fuca, near the mouth of Puget Sound.
There are two dams on the Elwha, which are slated for removal in what is to be the largest project of its kind in American history.
Before the dams come out scientists are scrambling to collect data on the current state of the Elwha, so they can see how things change with dam removal. And they’re using river otters as indicators of the health of the river ecosystem along its path to recovery.
In the second part of our series on the Elwha, Ashley Ahearn goes out looking for river otters.
River otters always leave the water to poop. So if you want to catch them, you’ve got to head to the bathroom.
Kim Sager-Fradkin is head wildlife biologist for the Lower Elwha Klallam Tribe.
“Because we had a latrine site here we set a trap,” Sager-Fradkin pointed out.
She’s out checking a series of traps, set up near what are called “otter latrines” along the banks of the Elwha River with her intern Selena Gray.
“They function as bathrooms but also as social congregation sites and scent marking sites. So multiple otters will use a single latrine and any individual otter will use multiple latrines up and down the river so there’s always a whole series of latrines up and down the river.”
Sort of like restroom stops along the freeway. But instead of funky smells and toilet paper on the floor, otters prefer to relieve themselves on leafy green river-front property, as Selena Gray explains.
“They like mossy rocks like this. This is their favorite kind of latrine.”
They like mossy rocks the best?
Is that kind of the luxury toilet paper?
River otters are one of the top predators on the Elwha. That means they’re great indicators of the health of this ecosystem, and how that health might improve once the dams come out. The problem is, right now no one really knows how many there are - either above or below the dams. But Sager-Fradkin hopes to solve that mystery using jellies.
“The jelly is a clear mucusy substance that the otters defecate and it appears to clean out their digestive tract of all these fish bones and fish scales. The good thing about jellies is it is chock full of genetic material,” Sager-Fradkin explains.
Sager-Fradkin has about 50 jellies in a freezer that she plans to send to a lab at the University of Montana to have genotyped. That way she’ll know roughly how many individual otters are frequenting the latrines, and she can estimate the local population from there.
She’s also set up infrared motion sensitive cameras at each of the traps to snap photos of the otters while they’re — ahem — going about their business.
Right now her rough guess is that about two dozen otters live in the 45 miles of the Elwha River.
“And because this project is now happening while dam removal is gonna happen. We’re interested in knowing the immediate effects on some of these animals that live around the reservoirs and move up and down between above and below dam habitat.”
Once an otter is trapped Sager-Fradkin takes it to a veterinary clinic where a radio transmitter is implanted just below the belly button so she can track the animal once it’s released.
Samples of whiskers, blood and toenails are also taken and those are sent to the Smithsonian Institute for Conservation Biology in Washington, D.C. where Peter Marra analyzes them for what are called “marine derived nutrients,” which otters get from eating salmon.
“So when a salmon comes into a river after being out at sea for a long time, most of the tissues that it’s accumulated while at sea have a very unique signature and when it dies those signatures work their way into the bugs, work their way into the water and work their way up that food web, so they’ll get into otters,” Marra says.
Marra can tell, from the chemical signatures that show up in an otter’s whiskers, whether it’s been eating fish like salmon, which spend time at sea, or fish like rainbow trout, which spend their entire lives in freshwater.
He says that when the dams went in on the Elwha about 100 years ago, the whole nutrient makeup of this ecosystem changed because the salmon weren’t able to make their way into the upstream habitat and deliver those nutrients from the ocean to the trees.
“We can take a core of a tree and I can sample those rings going back 100, 200, 300 years and I can tell you what years there were good salmon runs and what years there weren’t good salmon runs. I can do that above the dam and below the dam and I can tell you that it’s obvious that above the dam salmon have been absent from this system for a while whereas below the dam it’s obvious that there have been marine derived nutrients that have worked their way into the terrestrial ecosystem,” Marra says.
Kim Sager-Fradkin says otters are going to play a critical role in reconnecting the nutrient cycle from salmon to upland forests in the Elwha watershed.
“The otters along with all the other critters that consume salmon carcasses are going to be moving these nutrients. So it is going to have an ecosystem-wide effect as the fish come back. These nutrients aren’t just going to be left in the river. They’re going to be left in the forest as well and otters are going to play a big role in that picture.”
Sager-Fradkin is standing at what might soon become one of the most interesting trapping sites for otters. It’s the Lower Elwha Klallam Fish Hatchery, or for an otter, it’s kind of like McDonald’s. Otters have been known to get into hatcheries and chow down.
The trap here is empty but there are droppings all around, and that has Sager-Fradkin concerned for the future. As fish production here ramps up, otters might be tempted to take advantage of easy hatchery-raised prey, which could be a mistake that costs them their lives.
“I think there’s a balance that we need to find here. Yeah, we want salmon back in the river but we also don’t want to have to get rid of all the predators to make that happen. They have a place. I’m a big believer in predators.”
So far, otters haven’t killed any fish at the new hatchery, which opened in May and will be releasing Coho and Steelhead salmon into the Elwha in the spring.