PROVO — Some people call Utah Lake dirty. Others think it's smelly, bug-infested or polluted. But within those murky waters lives an endangered fish, and efforts to preserve it just might end up improving the lake environment for good.

"The bottom line for us is that we believe that by recovering the June sucker fish, we have to recover the ecosystem too, and in doing so I think we can make Utah Lake a better place not only for the June sucker, but also for the people who use it," said Reed Harris, director of the June Sucker Recovery Implementation Program for the Utah Department of Natural Resources.

Utah Lake is the only natural habitat of the June sucker fish, deemed endangered in 1986. Ever since, state officials have been making near-Herculean efforts to save the species, which at one point dwindled to just 500 fish.

The latest step is the reintroduction of almost 10,000 mature June suckers to Utah Lake from Red Butte Reservoir, where they were introduced in the early '90s.

Experts didn't expect the suckers to reproduce, as they were thought to require a river in which to spawn. But they reproduced in the reservoir, and have continued to do so.

A project to improve the reservoir's dam means it will be drained in coming months, which opened the door to send a large portion of the growing population to Utah Lake.

Wildlife planners hope the reintroduction will mean more spawning in the Provo River this June, and in coming years, as well. A larger fish population will help scientists better understand the June suckers.

As it is, the fish are very rarely seen in the lake, and scientists have only observed them when they swim up the river to spawn each June.

"Now that numbers are increasing, we can better understand the fish's needs," said Chris Keleher, a biologist from Central Utah Water Conservancy District.

One key need of the June sucker is fewer carp in Utah Lake. The non-native carp constitute 90 percent of the life in the lake, and their presence has severely hampered the June sucker's ability to survive.

"The problem with carp is, they uproot vegetation in the lake, disturbing sediments and making the water muddy," Keleher said. "They are a major habitat destroyer."

Lake-bottom vegetation is key for the June sucker because it provides a place for young fish to hide from predators. Vegetation would also affect the ecosystem in a variety of other positive ways, according to Keleher.

The Conservancy District and the Department of Natural Resources have been studying the feasibility of removing the carp, and have concluded on a preliminary basis that it may be possible.