Why California's salmon species are in hot water

May 22, 2017, 7:13 a.m.
A salmon tries to jump a salmon ladder at a dam.
Photo: bpperry /iStockPhoto

California's genetically unique salmon populations are in dire straits, according to a new report on the status of California's native salmon from University of California, Davis.

In "State of the Salmonids II: Fish in Hot Water," the researchers say: "At the current rate, 45 percent of California salmonids are likely to be extinct in the next 50 years. This includes 11 of 21 anadromous species and 3 of 10 inland species. In 100 years, 23 of the remaining 31 species (74 percent) are likely to be extinct if present conditions continue."

The primary culprit, posing a high threat to most of the species studied, is climate change. Climate change affects the temperature and amount of water available to salmon, which need plenty of cold, free-running water to complete their reproductive cycle. Other threats brought on by climate change include a loss of habitat, rising sea levels and an altered food web in the ocean that will dramatically impact the survival of adult salmon.

But climate change isn't the only problem. Agricultural practices, including the production of marijuana, wine and food crops, create serious issues with sediment, pollutants and water management practices that are fouling the watersheds.

"The juveniles of Chinook salmon, by contrast, spend just a few months in freshwater before migrating to the sea, which makes them somewhat less vulnerable to inland habitat loss," notes NPR. "Still, Chinook salmon — the only salmon species that is commercially fished and marketed in California — are not doing well, either. The report says six of California's eight genetically distinct Chinook populations are likely to disappear."

Without some protective steps made by humans, more than half of the genetically distinct salmon populations of the Golden State will be gone in 50 years.

CalTrout outlines several steps that could help minimize the damage and protect native fish species from disappearing. They rely on restoration of habitat and crafting better strategies for minimizing the harm done by human influence.