The June Sucker Recovery Implementation Program this week began testing the viability of using controlled flows out of Deer Creek Reservoir to speed the native fish species' larvae down the Provo River and into the lake.

The flow experiment began Tuesday and concludes today. Additional water is being released from the dam during a seven-hour period between 2 p.m. and 9 p.m., in increments that eventually increase to 300 cubic feet per second. The release requires about 125 acre-feet of water each day.

"The additional water is being released to see if releases from Deer Creek Reservoir can increase the survival rate of young June Sucker making their way down the Provo River to the lake," said Chris Keleher, assistant director of the June Sucker Recovery Program. "The additional water may help the young fish safely reach suitable habitat in the lake that is not available in the river channel."

The U.S. Fish and Wildlife Service declared the June Sucker an endangered species in 1986, finalizing the recovery plan in 1999.

Essentially, the goal of the flow test is to time the Deer Creek releases with the movement of the larval, or hatched fish, into what is called "the drift," with the river surges pushing the young fish down towards the river's mouth.

So far so good, according to Division Wildlife Resources Biologist Krissy Wilson.

"They were very successful in delivering the flows to the lower Provo that we needed to move the larval fish," she said Wednesday. "From past research we knew when they entered the drift. We needed sufficient flows to move the fish once they were in the drift, and that's exactly what happened. It was perfect."

The flow experiment was conceived largely as a way to overcome what had become a bottleneck for the larval fish in the lower part of the river. Dredging and channeling the Provo for flood control has created a u-shaped channel out of what was formerly a river delta environment. Predators also posed a problem for the young June Sucker.

The increased flows, it is hoped, will carry the fish through the bottleneck and into safer habitat.

jbaird@sltrib.com