New Mexico

For the Fish: Restoring the Upper Colorado Basin

Aggressive strategies along the San Juan River are enabling endangered fish to recover—and providing a Navajo community with the benefits of easier access.

“Now we know the fish are using the channels we built.”

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High spring flows used to annually scour vegetation from the San Juan River floodplain. But that’s not the case today, due to the Navajo Dam and subsequent invasion of non-native Russian olive trees armoring the riverbanks. 


The result is a deeply cut, fast-flowing river—not the slow moving secondary channels and backwaters that provide habitat needed for young fish to reach adulthood. 

This lack of sustainable nurseries has contributed to declining populations of Colorado pikeminnow and razorback sucker, landing both native fish on the federal endangered species list. 

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The Nature Conservancy, in partnership with the San Juan River Recovery Implementation Program and the Ancestral Lands Youth Conservation Corps, is restoring habitat diversity to sections of the river so fish populations can again thrive

So far it’s working, according to Dave Gori, the Conservancy’s director of science in New Mexico. 

This year was the first in a three-year study to understand how fish are responding to the restored habitat. 

“In the first sampling this spring, we caught year-old pikeminnow in our restoration channel, and none of them in the control channel. Now we know the fish are using the channels we built,” said Gori. 

As plants grow and the flows reshape the sandy bottom in the restored channels, the habitat will become more varied. “Over time,” he continued, “we think it’s going to get better and better.” 


With 17 acres now cleared of Russian olive trees, the Navajo community has easier access to the river and the floodplain again. There are beautiful cottonwood groves now used for picnics or camping. 

And that’s not all. “The restoration project also provides wood and jobs for the community,” said Gori. 


Preparations for the next phase of the project are currently underway. A series of wetlands connected to the river during high spring flows will provide habitat, currently lacking along the river, which the larvae need to grow into young fish. 

Gori believes this next step may be the crucial missing link for endangered self-sustaining fish populations in the San Juan. 

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