At a Glance Many of California's salmon, trout and steelhead species could be extinct in 100 years, according to a new study.

Climate change and agriculture are cited as reasons for the likely mass extinction.

The study's authors say the species can be saved through restoration efforts.

Nearly two dozen species of California salmon are expected to go extinct within 100 years if measures to preserve the fish aren't taken soon, according to a new study.

Titled "State of the Salmonoids II: Fish in Hot Water ," the study performed by California Trout and the UC Davis Center for Watershed Sciences found that 45 percent of the salmon, steelhead and trout native to California will likely be gone in just 50 years. The report follows a 2008 study that didn't have nearly as many dire findings.

"At the current rate, 45 percent of California salmonids are likely to be extinct in the next 50 years," said the study. "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."

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<img class="styles__noscript__2rw2y" src="https://dsx.weather.com//util/image/w/ap_17136599641923.jpg?v=at&w=485&h=273&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0" srcset="https://dsx.weather.com//util/image/w/ap_17136599641923.jpg?v=at&w=485&h=273&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0 400w, https://dsx.weather.com//util/image/w/ap_17136599641923.jpg?v=ap&w=980&h=551&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0 800w" > In this April 24, 2014, file photo, young salmon that have been transported by tanker truck from the Coleman National Fish hatchery are loaded into a floating net suspended on a pontoon barge at Mare Island, California. (AP Photo/Rich Pedroncelli) (AP Photo/Rich Pedroncelli)

An obvious culprit for the dire outlook, according to the study, is climate change. Salmon and trout need clean, cold water to thrive, and a warming planet likely means less snow and frigid water flowing downstream, where the salmon live. This means far less suitable water for the fish – if the streams don't dry up completely in the summer, the study said.

The authors also cite agriculture as a major threat, as farmers pump water out of rivers, leaving them shallow and warmer. The waterways can also be polluted with chemicals from fertilizers and pesticides, the report added.

"This report should rightly be considered an alarm bell, but it should also be seen as a roadmap for how we can correct course to better support native aquatic species ," lead author Peter Moyle, the associate director of the Center for Watershed Sciences, told SFGate.

The study's authors remain hopeful that habitat restoration and other protective measures can reverse the damage already done and prevent a mass extinction, but time is limited.

"We do still have time, and we are optimistic that with some effort, we can have a future that involves these fish ," CalTrout executive director Curtis Knight told reporters, as reported by NPR.

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