Habitat restoration efforts have led to the reappearance of wild salmon in one California creek, according to Phys.org.
A University of California, Davis, study identified the genealogy of Chinook salmon returning to Putah Creek in Northern California. By examining the water chemistry contained in salmon ear bones, researchers were able to tell that the fish coming back were the same ones that had been born there.
This means the salmon were fully wild, not strays from nearby hatcheries. That said, the wild salmon are descendants of hatchery salmon. This is significant, as hatchery fish are usually characterized as having inferior genetics unsuitable for surviving in the wild. It could also mean that salmon hatcheries could productively coexist with wild populations.
“The fact that you have Putah Creek-origin fish is a big deal,” said study author Andrew Rypel, per Phys.org. “To have a growing, stable population that’s natal means it’s a well-managed ecosystem. It means we’re taking care of the water and the land the right way, and that there’s a future for fish in that place. It also shows there’s hope for other streams that are degraded.”
The return of the salmon is the result of intense habitat rehabilitation. Dams, warming, runoff, and drought are just some of the barriers facing salmon populations in addition to natural challenges. Other habitat protections, such as one in the United Kingdom, have also been able to bring salmon populations back.
Salmon are a vital part of ecosystem health. Their heroic return upstream to breed and die leaves a wealth of nutrients vital for nearby trees and scavengers, including bears. When wild salmon populations fail, so does everything that relies on them.
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Researchers are hoping this study is optimistic for both hatcheries and habitat protection.
“The idea that hatcheries can be part of the solution might take people off guard,” Rypel said. “But there may be positive effects so long as the salmon have a good place to go. There’s a lot of potential to have more Putah Creeks out there.”
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