Great story about how technology can help nature, from KQED News.
Right now, thousands of 1-year-old coho salmon, or smolts, are making their way to the Pacific Ocean from the Russian River in Sonoma County.
But most of these endangered fish weren’t actually born in the river’s tributaries. Instead, they were bred and raised at the Warm Springs Fish Hatchery in Geyserville.
At the beginning of this century, the coho in the Russian River were almost completely eradicated.
“We were seeing less than 10 adults returning to the Russian River watershed, when years ago there were thousands of fish returning,” says Mariska Obedzinski, who helps run California Sea Grant’s Russian River Salmon and Steelhead Monitoring Program.
The Russian River watershed was once a stronghold for Central California’s coho salmon population, but Obedzinski says things like extreme habitat loss and drought years have led to the downturn. According to California Sea Grant, the state’s coho has dwindled down to an estimated 15% of its population in the 1940s.
Obedzinski’s group, along with federal and local agencies, have been helping rebuild the coho population in Sonoma County through a combination of restoration efforts, monitoring and the hatchery program, which began in 2004. That was when some of the last handful of coho born in the watershed were captured and bred.
“It was a last attempt to really save the coho salmon in the Russian River watershed,” says Obedzinkski.
Now the program releases thousands of smolt, at different life stages, throughout the year in the Russian’s tributaries. More than 1.5 million smolt have been released since the program began. The fish are closely monitored to see how they’re surviving, but watching over these young fish after releasing them into the wild is no easy task.
Teams of biologists go out daily to check traps in five of the watershed’s creeks, hoping to find a mix of healthy hatchery-born and natural-born salmon.
A contraption, made up netting and pipes, funnels anything going downstream into a covered, wooden box. On any given day, anywhere from a handful to hundreds of smolt can be found inside. And sometimes, other aquatic animals get stuck in the trap too.
“If there’s something big, you can hear it splashing around in there,” says Nick Bauer, a fisheries biologist with California Sea Grant.
Bauer and his team count and scan every single coho they find before letting them go back downstream to the Russian River. A metal detector helps identify which fish have an implanted wire tag, which means they’re hatchery-born.
Then a portion are measured and weighed. An even smaller portion get trackers implanted in them, which help biologists monitor the migratory habits of the smolt and find out whether the fish come back to these creeks as adults to spawn.
“We’d like to see wild fish being able to complete their life cycle in the streams on their own,” says Obedzinksi. “We ultimately would like to see the whole hatchery component go out of business.”
Obedzinksi says the program is making progress. About 1,200 natural-born smolt were recorded in the watershed in 2018, the second highest amount documented since the program began, according to a recent report from California Sea Grant.
“If this program wasn’t in place, coho salmon would pretty much be extinct in the watershed,” says Bauer.
Retrieved June 10, 2019 from https://www.kqed.org/news/11753540/hatchery-born-coho-save-species-extinction-russian-river