Fish species illegally introduced at Utah reservoir within Colorado River drainage

Utah wildlife officials are again reminding people that it’s illegal to dump fish into bodies of water after state biologists discovered an unapproved species had been introduced at a southeast Utah reservoir.

Biologists found smallmouth bass at Loyds Lake, located within the Colorado River drainage located southwest of Monticello, while doing routine surveys, the Utah Division of Wildlife Resources reported on Wednesday. The reservoir is home to rainbow trout and green sunfish, but not bass, largely because of its proximity to the Colorado River and the threat to native fish within it.

“Due to several endangered fish in the Colorado River, we partner with other agencies to ensure that our sportfish stocking does not interfere with the recovery of native fish. The stocking of sportfish in any drainages in the Colorado River Basin is therefore highly regulated,” said Trina Hedrick, the division’s sportfish coordinator, in a statement. “This illegal introduction is very problematic.”

It’s unclear when the fish were dumped in the reservoir, but the division warns that unapproved species can prey on or outcompete other species approved for a body of water. These include sportfish and native species. New species can also introduce diseases into an ecosystem or impact water quality.

They can also destroy fisheries, which is why it’s a class A misdemeanor to introduce fish into new locations, Hedrick added.

“If we were going to consider the stocking of smallmouth bass, it would get a thorough review and escapement evaluation, and it is highly unlikely that we would stock the species here,” she said.

Anyone who witnesses a person attempting to dump or relocate a fish, or discovers an unauthorized fish species in a body of water, is encouraged to contact state wildlife officials at 800-662-3337.