Effort Underway To Save Endangered Fish In Southern Utah

SCOTT M. MATHESON WETLANDS PRESERVE, Moab – If you were to encounter a full-grown razorback sucker, you’d probably think they could do a pretty good job taking care of themselves. They look healthy, tough, maybe even a little mean.

But in fact, adult razorback suckers are very rare, and the species is in danger of going extinct. It’s largely because human activity has drastically altered the Colorado River, changes that helped make baby razorback suckers exceptionally vulnerable in their first weeks and months of life.

Now a major effort is underway to help them survive because, in much of the Colorado River drainage, they’re in deep trouble.

“We think of it as an indicator of the health of the river system,” said Linda Whitham of The Nature Conservancy. “When the fish are not doing well, obviously there’s something wrong with the system itself.”

The rescue project is on the Scott M. Matheson Wetlands Preserve, a property owned by The Nature Conservancy on the fringes of Moab alongside the Colorado River. Over the last few weeks, construction crews have been creating a special side-channel that will carry river-water into the wetlands during periods of higher water. It’s designed to mimic – on a small scale – the natural system of annual spring flooding that’s been disrupted over the last century or so by dams, diversions and other human activity.

“We don’t have the same magnitude of flood events, or the same duration, or even the same timing,” said Zach Ahrens, a fish biologist for the Utah Division of Wildlife Resources, one of several agencies that have partnered on the project.

In the spring, the suckers spawn and hatch tiny babies in the main current of the river. The plan is to divert the higher spring flows through the new channel into a large pond in the Matheson wetlands. Actually, in recent years it hasn’t really resembled a pond because it contains so little water. The new channel is aimed at refilling it from time to time to give the larvae of razorback suckers an alternative, temporary habitat.

“Away from the main channel allows for a little bit warmer water, which allows the fish to grow more quickly,” Ahrens said. “It also allows them some refuge from the turbulent currents that occur during spring runoff.”

If they stay out in the main channel of the river, the larvae are highly vulnerable to being eaten by non-native fish that have taken over the Colorado. “They’re maybe a half an inch long,” Ahrens said. “They’re tiny little translucent noodle-looking things.”

But if they can spend a few months in an off-stream nursery, they can come out big and strong.

“If we can bring them into a safe harbor, into a nursery and give them the months they need to grow to a sufficient size, and then release them back into the river, then they can compete” Whitham said.

When they re-enter the Colorado River, they’ll have a better chance of stand up to hungry non-native predators that were accidentally or deliberately introduced in the last few decades.

“If we can help bring back these populations of native fish, who have been around for millions of years, and get them to sufficient sizes, then we’ll know that we’re doing something right,” Whitham said.

The project is being built in phases because all the funding hasn’t been lined up yet. The Nature Conservancy hopes to fill the gap with state and federal grants as well as private contributions.