Drought impact on Russian River watershed challenging fish survival
MONTE RIO, Sonoma County -- As Northern California finds itself between two desperately needed rounds of rain, compounding years of drought have taken a toll across the state and particularly on our watersheds.
For several years now, researchers have been trying to understand more about how the Russian River watershed is responding to all of the dry years. It is a study focusing on the effects of a changing climate and how fish might survive those conditions.
"Survival is impacted by so many things," explained Sarah Nossaman of the Russian River Monitoring Team. "But only the fish that are in wet, connected areas have a really solid chance of survival in these dry years."
Nossaman and two other team members were sloshing their way through Dutch Bill Creek in the hills of Western Sonoma County, trying to understand this stream like a doctor knows a patient; Assessing its health in another dry year.
"So yes, in a sense we are measuring the drought," Nossaman said. "We're measuring what that really means for these fish, what conditions they are experiencing."
"The ones that we are focusing on today are temperature and dissolved oxygen," explained researcher Jason Held.
Of course, fish don't just need water, they need good, oxygen-rich water that is moving.
"Water coming in from downstream," Held said. "But then all this oxygenation that's happening with the bubble curtains calculation to the gravel and all that."
Eventually, the fish will need to keep moving as well.
"They are going to need a connection at the mouth out into the estuary and the ocean," Nossaman said.
For a coho or a steelhead in Dutch Bill Creek, the big intersection on the way to the Pacific is the junction with the Russian River in Monte Rio. But those fish have to be able to get there. This project is about understanding how creeks are changing, and what kind of odds the fish are facing as they try to make it out and back.
"You know, who even has a chance to survive," Nossaman said of the work. "There are so many factors related to survival and it's hard enough for them to survive."
"We see these conditions plummet in pools that are disconnected from surface flow," Held said of tough conditions in dry years.
Disconnection is the real killer, places where the creek simply dries up.
"That was once a pool, as you can see from the scour," Nossaman said, pointing to a dry creek bed. "As we head downstream there are some very large calls that are completely dry as well."
Year by year, the team is piecing together a picture of a watershed stressed by drought; More disconnected streams, tougher conditions. But all the fish know how to do is keep trying, and some coho are managing pretty well.
"The fact that we are able to see so many fish," Nossaman said, looking at a pool with young coho circling. "And not even in the pool, but like standing on the edge of the pool, indicates there was really good successful spawning in this reach of stream."
The hope is that a better understanding of the creek, and how it's changing, can provide better strategies for how to give more fish better odds of surviving.
"Also, just to kind of understand better what we are facing," Nossaman said. "What we are potentially losing. What sort of scale of work is going to be needed if we're going to help these fish to survive under climate change conditions."
