EMERY COUNTY, Utah (ABC4) — The Utah Division of Wildlife Resources said the illegal introduction of Utah chub at the Millsite Reservoir has put another fish species at risk.

The DWR said the species at risk is called the bluehead sucker, which lives in the Millsite Reservoir. The DWR called the bluehead sucker “a species of greatest conservation need” in a social media post.

“The illegal introduction happened in the past few years, as we found several age classes in our sample,” the DWR said.

According to the DWR, officials have been working to ensure a “healthy balance” in the ecosystem at the Millsite Reservoir that supports both recreation and the conservation of the bluehead sucker.

“The illegal introduction of Utah chub has put it at risk,” the DWR said.

In its post, the DWR reminded Utahns that moving fish between bodies of water in Utah is illegal — especially because those introduced fish may prey on other species, including native or endangered species.

“Bucket biology could also introduce disease into the waterbody because the fish and any water introduced have not been certified disease-free,” the DWR said.

What is the Utah chub?

Utah chub is the common name for the species Gila atraria, and are often found in freshwater areas — such as lakes or creeks, according to the website FishBase.

The fish are said to have a “deep, compressed body” with large eyes and a short snout, FishBase said.

“Introduced populations often reach great abundance and become serious competitors with sport fish, especially trout,” according to a USGS Nonindigenous Aquatic Species fact sheet.

Utah officials have said the illegal introduction of the Utah chub at the Millsite Reservoir has put the ecosystem of the reservoir at risk.

What is the bluehead sucker?

According to the DWR’s Utah species field guide, “bluehead sucker” is the common name for the species Catostomus discobolus, which is native in parts of Utah, Idaho and several other states.

The fish is said to have a modified mouth that helps it scrape algae from the surface of rocks, as it dwells at the bottom of the bodies of water it is found in.

“In Utah, bluehead suckers have been reduced in numbers and distribution due to flow alteration, habitat loss/alteration, and the introduction of nonnative fishes,” the DWR said in its guide.

Utah officials said the main cause of population decline for this species is alteration to and loss of its habitats.

Why is moving fish illegal in Utah?

The DWR has asked that Utahns “Don’t ditch a fish,” and has also encouraged Utahns to know the law regarding moving fish.

The most important things to note are that introducing fish into Utah waters is illegal, and transporting live fish between waters is a violation of state law.

Additionally using live baitfish while fishing is illegal in Utah, and releasing any species of fish into a body of water in the state is illegal.

The DWR has an updated guidebook with the most recent fishing regulations available online.