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Invasive smallmouth bass make it through Glen Canyon Dam into mainstem Colorado River, threatening native fish

The National Park Service says smallmouth bass have been found in the mainstem Colorado River below the Glen Canyon dam. The announcement comes as lake levels drop to unprecedented lows.

Smallmouth bass are a predatory non-native fish that have adversely impacted native and federally protected fish in the upper basin of the Colorado River over the last 20 years.

In a press release, NPS and the Department of the Interior say lower water levels at Lake Powell and rising temperatures in the Colorado River have increased concerns that non-native, warm-water predators, including smallmouth bass, could pass through the dam and begin reproducing.

Researchers have spent decades working to restore native fish populations below the dam.

If these warm-water predators establish populations in the mainstem river, officials say it’s likely they would negatively impact native fish communities in Glen Canyon National Recreation Area and in Grand Canyon National Park.

NPS encourages anglers to report any observations or catches of smallmouth bass below the dam.

If caught, NPS says to remove the fish, put on ice and contact staff at Glen Canyon National Recreation Area or Grand Canyon National Park with a description of the location where found. Report findings to: Jeff Arnold, Glen Canyon National Recreation Area, or Brian Healy, Grand Canyon National Park,

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