News about Colorado's Natural Resources   Email Article

Colorado Parks and Wildlife

Invasive goldfish dumped at Teller Lake #5 in Boulder

BOULDER, Colo. -- Colorado Parks and Wildlife (CPW) is seeking information on who may have released goldfish into Teller Lake #5 off Arapahoe Road in Boulder. The exotic species, which were first noted by Boulder Open Space Rangers March 13, are now present in the thousands and will likely need to be removed to maintain the integrity of the lake.

"Goldfish are not a native species and are very harmful to the local aquatic ecosystem," said Kristin Cannon, district wildlife manager for Boulder. "We strongly encourage the public not to dump their unwanted pet fish in our waters. It is bad for our environment as well as illegal."

In November 2012, the removal of koi goldfish from Thunderbird Lake in Boulder put a spotlight on the threat exotic species represent to Colorado's aquatic wildlife. The electro fishing effort yielded 2,275 nonnative goldfish, which had likely been reproducing in the water for two to three years, based on the age classes of fish removed. What likely began as the deposit of unwanted pets into the lake grew into a problem of enormous proportions.

"Most people don't realize the far-reaching effects of introducing exotic species to the environment," said Ken Kehmeier, senior aquatic biologist for CPW.

"Nonnative species can be devastating to native populations by causing disease outbreaks and creating competition unbalance. It's an issue that anyone concerned with our environment should know about."

Zebra and/or quagga mussels were identified in eight reservoirs in Colorado in 2008 as a result of a multiyear statewide sampling effort conducted by the CDOW, in partnership with Parks, the U.S. Fish & Wildlife Service and the U.S. Bureau of Reclamation. Zebra mussels, and their close relatives quagga mussels, are highly invasive aquatic species that negatively impact plankton communities, fisheries, water based recreation, and water supply and distribution systems for municipal, industrial and agricultural uses.

Also of concern is the "bucket brigade"-- anglers who choose to dump sport fish of their choosing into Colorado waters. While some nonnative fish are stocked at times, aquatic biologists only do so after a rigorous biological assessment to determine what can be stocked and where for a balanced ecosystem.

"We work closely with anglers via creel surveys and check with local bait shops on a regular basis to find our anglers' desires and aspirations for fishing in the state," said Ben Swiggle, a northeast region aquatic biologist. "We carefully stock for optimum conditions to get people outdoors, offer recreational opportunities, and to better the habitat of the state."

Colorado Parks and Wildlife is dedicated to protecting wildlife and fisheries for future generations. Managing over 9,000 miles of stream segments with average or better fisheries, CPW maintains 6,000 miles of water open to the public.

Photos available upon request.

CPW is an enterprise agency, relying primarily on license sales, state parks fees and registration fees to support our operations including 43 state parks covering more than 220,000 acres, big-game management, hunting, fishing, wildlife watching, camping, motorized and nonmotorized trails, boating and outdoor education. CPW's work contributes approximately 6 billion in total economic impact annually throughout Colorado.

Colorado Parks and Wildlife