From KUNC (Luke Runyon):
The temperature is hovering right around 90 degrees the day Dale Ryden and I float down the Colorado River near Grand Junction, Colorado. The water looks so inviting, a cool reprieve from the heat, but if either of us jumped in we’d be electrocuted.
“It can actually probably be lethal to people if you get in there,” Ryden, a fish biologist with the U.S. Fish and Wildlife Service, says.
Next to us, Ryden’s coworkers cruise by in grey and blue inflatable rafts, outfitted with a metal sphere — the size of a disco ball — hanging off the front. A generator on the back of the raft sends an electric charge through the ball into the turbid water. Ryden compares the color to a glass of Ovaltine. What lies beneath the surface of the sediment-laden water is a mystery.
“To get at the animal we’re studying we have to actually find ways to capture them and take them out of their natural habitat,” Ryden says. “And so one of the ways we can do that is electrofishing.”
The fish that venture near the electrified rafts are momentarily stunned and pulled out of the water with nets. Today’s mission is to remove nonnative fish — like small mouth bass — which feed on the young progeny of the four endangered species found in the river. The bass will be collected, measured, weighed, stored in bags and eventually discarded in a local landfill.
Meanwhile, any of the four endangered species — bonytail, razorback sucker, Colorado pikeminnow, and humpback chub — we encounter will be treated with care and released back into the river.
Ryden has a tough, and some would say impossible, job. Everyday he tries to find ways to help the fish that evolved to live only in this river system — one of the most engineered ecosystems in the world — survive.
Fish in the Colorado River are a product of harsh conditions.
Over millions of years the rushing, sediment-laden water sculpted their bodies with characteristic ridges and bumps, making them well-equipped to handle its highs and lows. But human interference in the rivers they call home has caused a few to nearly go extinct.
“They’ve survived three explosions of the Yellowstone supervolcano. They were here when mastodons and woolly mammoths went extinct,” Ryden says.
He ticks off the historical events that upended human civilization while the fish just kept swimming. The razorbacks and humpback chubs didn’t bat an eye while Roman and Egyptian empires collapsed, while America was colonized, while soldiers fought the Civil War.
It was the era of big dam building that fundamentally altered the fish species’ home. Within the last 100 years or so, Ryden says, dams and other water diversions have made life close to impossible for these fish. Then people started adding in toxic chemicals, pharmaceuticals and a suite of invasive fish.
“Call it the death by a thousand cuts,” Ryden says. “So they could survive any one of those problems probably fairly well. When you start throwing them all on top of them, then it becomes a lot more problematic.”