About 30 June suckers, an endangered species, apparently were clubbed to death while spawning in the lower Provo River, state wildlife officials say.

The June sucker is a large fish found only in Utah Lake. It was placed on the list of endangered species because of a rapidly declining population and limited range.Randy Radant, chief of non-game for the Utah Division of Wildlife Resources, said the fish move out of Utah Lake and into shallow areas of the lower Provo River to breed during the spring.

The breeding areas are also popular recreation areas for people living near the river.

The spawning fish are visible when the water level is low, and they become easy targets for someone swinging a club or stick, Radant said.

He said the deaths are a "significant loss" to the species.

Biologists last year counted only about 200 breeding June suckers in the Provo River, so the loss of 30 fish could represent the elimination of almost 15 percent of the total breeding population of the species.

Past studies have shown that almost all of the June suckers in Utah Lake are more than 30 years old, which may indicate the species has not been reproducing successfully for many years.

Radant said if that's the case, the fish might not be replaceable.

"Our priority is to protect every reproducing fish in that population and then try to build up the spawning population," said Bob Ruesink, state supervisor for the U.S. Fish and Wildlife Service. "Because of that, this incident definitely is important."

Radant said the division is requesting information from anyone who may have knowledge of the incident, and the division and the U.S. Fish and Wildlife Service are offering rewards for information leading to the arrest and conviction of those responsible for killing the fish.

Federal officials have the option of filing civil or criminal charges under the Endangered Species Act. The civil charge carries of maximum fine of $10,000 for each violation. The killing of 30 endangered fish could theoretically be interpreted as 30 different violations, Ruesink said.

The federal criminal charge carries a maximum penalty of one year in prison and a $20,000 fine.

The state charge is a Class-B misdemeanor, which carries a maximum penalty of six months in jail and a $1,000 fine.

Radant said the June sucker looks like the common Utah sucker.