News Pet Fish Invasion Troubles Fisheries



‘Pet’ fish invasion troubles fisheries
10th May 2021

By Justine Thompson

Community fisheries in Utah are being devastated by koi that have been released by their owners.

According to the Utah Division of Wildlife Resources, nearly all community fisheries in the St. George area now host colonies of koi fish. Southern region aquatic program manager Richard Hepworth said the fish were generally introduced by families and individuals dumping unwanted ‘pets’ into the nearest pond or waterway.

“Koi are not very desirable for table fare, and they compete with species like rainbow trout that
people tell us they want to catch,” he said.


He fears that the koi reproduce so quickly that even community removal programs will not be enough to reduce the population.

Leisure fisherman Kelly Giacomazza told the St George News that he isn’t troubled much by koi since they don’t tend to bite with the bait he uses.

He said: “Personally, I don’t mind the koi fish because they’re cool looking. I was surprised to see how many there are – there’s a lot: red ones, orange ones, yellow ones, white ones and even some that are spotted like dalmations.”

But Richard Hepworth said. “It all comes down to doing our very best to manage not just a specific pond or a lake, but a greater ecosystem for multiple different species and multiple uses. When you start introducing new species, they can mess with that whole ecosystem.

“It is against the law to release a pet into a pond or lake in the wild,” he added.