Editor's note: This story comes to Living on Earth by way of EarthFix.
The largest dam removal project in U.S. history has been taking place since 2011 on the Elwha River in Washington State — a bid to restore historic salmon and steelhead trout runs.
So much sediment has been released from above the two dams that the final part of the removal was put on hold temporarily. But the murky water hasn’t stopped fish from making the journey upriver to spawn in the reopened habitat.
Mike McHenry stands next to a water treatment plant and a fish hatchery not too far from the mouth of the Elwha River. He’s a fisheries habitat biologist with the Lower Elwha Klallam tribe. Put on a pair of polarized sunglasses and the murky stream quickly reveals torpedo-shaped bodies moving slowly through the brown water.
"You are looking at several wild winter steelhead. These are the native remnant stock of the Elwha River," McHenry said.
These fish are some of the last of their kind here. Biologists estimate that there’s somewhere between 200 and 300 wild steelhead left in the Elwha. These fish have just returned from several years in the open ocean, fattening up, dodging killer whales and other predators — and now they’re back to lay eggs in their home river.
But the area below the dam, the murky water, is the wrong place to lay.
"What we’re going to try to do today is capture these fish, tag them, and relocate them into the Little River, which is a tributary in the middle part of the Elwha River, which has very clean water and high quality habitat," he said.
The habitat is in such good shape because it was protected by the dams that were higher up on the river. Those dams are now gone, but removing the dams released a lot of sediment that's built up behind the remaining dam.
McHenry's team of biologists net the fish and carry them up the hill one by one, where they’re put in a large tank. There, the team gathers DNA samples, measures each fish and attaches a radio tag so they can keep track of it once it’s released upriver.
John McMillan, a contract biologist with the National Oceanic and Atmospheric Administration works with McHenry and the tribe. Peering down into the tank, he pauses.
"This is probably brood stock," he said.
This is a key moment. A decision will have to be made. Brood stock are fish that has spent time in a hatchery, even though its parents were wild. Research has shown that when some types of salmon and steelhead are raised in captivity they can become domesticated. Other research suggests the brains of hatchery fish don’t grow as big and they don’t produce as many offspring that survive once they’re released.
"We don’t know for sure but this fish has a worn dorsal which is kind of an indicator that it was raised in a hatchery. The fish chew on each other’s fins in the hatchery," he said.
Do the biologists bring this hatchery fish up into the pristine habitat above the dam? Or do they leave it here? It’s a decision that government agencies, wild fish advocates and the Lower Elwha Klallam tribe have fiercely debated for years.
With so few wild salmon and steelhead in the Elwha, should hatchery fish like this one be used as sort of junior varsity subs to boost the overall numbers of fish in this river as it recovers from the dam removal?
The team decides to bring two hatchery-raised fish upstream, along with six wild steelhead. Using fish from hatcheries is part of the Elwha River Fish Restoration Plan, which has sparked a lawsuit.
Jamie Glasgow is the director of science and research for the Wild Fish Conservancy, one of the non-profits who filed the lawsuit against the lower Elwha Klallam tribe and several governmental agencies responsible for the Elwha restoration project.
"We believe that wild fish in the Elwha would recover better in the absence of hatchery influence," Glasgow said. "You cannot raise a fish in a hatchery without having a negative impact on its genetics and its behavior."
Rob Jones, chief of production for inland fisheries with the National Marine Fisheries Service — a lawsuit defendant — says hatcheries are necessary for steelhead survival in the Elwha.
"What is very clear to us, crystal clear to us, is that the fish are in such bad shape and the conditions in the river are so unprecedented that any risk that the hatchery poses to these fish is more than outweighed by the benefits," he said.
Jones says the hatcheries will be phased out when salmon and steelhead numbers increase. But the plan doesn't give a set timeframe or a hard date when the hatcheries will be removed.
The dam removal going on on the Elwha is truly a grand experiment. No government or tribe has ever tried anything like this before — and no one knows exactly how it will play out.
Right now, the river is a difficult place to live if you’re a salmon or steelhead, but it’s not impossible. Last year 500 wild Chinook made the journey above the lower dam to spawn on their own. So far, only a few wild steelhead have made that trip without the help of McHenry's team.
So, until they’re told otherwise, the biologists will release the hatchery-raised fish with the wild steelhead into the newly available habitat above the lower dam.
The biologists have DNA samples from all of the fish they’re releasing — hatchery and wild. McHenry and McMillan say that will allow them to see who spawned with whom and which pairings led to more successful offspring.
"It’s all we have to work with and you figure that nature will sort it out ultimately. That's what you hope for, that nature sorts out who wins and who loses and it will," McMillan said.