Pueblo Reservoir surveyed for invasive mussel

PUEBLO - When looking for cancer, a physician may start by searching for lumps.

State and federal officials are taking the same approach at the Pueblo Reservoir in the search for zebra mussels, an invasive species that has spread like a cancer through much of the Midwest.

The mussels recently turned up here, the first time they had been discovered in Colorado. Tuesday, state and federal officials began surveying the lake with an underwater camera to find out if the discovery of two adults and larvae was a fluke or the warning sign of a larger invasion.

“It may be very early in the invasion, and we have to see what we find out, and that will affect our strategy a great deal,” said Rob Billerbeck, biologist with Colorado State Parks, which oversees recreation at the reservoir, also known as Lake Pueblo State Park.

The Eastern European zebra mussels were introduced to the U.S. by oceangoing vessels in the late 1980s. They have since spread from the Great Lakes throughout the Mississippi River basin, usually by hitching rides on recreational boats.

Before the discovery in Pueblo — made during routine testing in November and confirmed last month in a laboratory — the farthest west they had been found, other than one location in California, was in the Arkansas River in central Kansas.

Fred Nibling, an invasive species researcher for the U.S. Bureau of Reclamation, which owns the reservoir, said the mussels could have severe impacts on the lake.

They could compete successfully against smaller fish, which could result in a reduction in size and population of larger fish that feed on the smaller ones.

They could make the water clearer by eating all the plankton, resulting in blooms of underwater weeds. They could clog beaches and shores with shells, which, in some Great Lakes areas, has caused beaches to be shut down.

While there is no human health threat, they have been known to clog pipelines and water systems — a big concern in Pueblo Reservoir, which provides 52 billion gallons of water a year to several cities. The Fountain Valley Conduit pipeline brings water from the reservoir to Colorado Springs, Fountain and Security, and plans are in the works for the Southern Delivery System, a $1 billion pipeline project to carry water 40 miles from the reservoir to Colorado Springs.

After a week of surveying the two marinas with the underwater camera, a team of divers will go over the marinas by hand, feeling hulls, docks and other hard surfaces for tiny lumps.

There is urgency to the search. The mussels will begin reproducing when the water temperature hits 52 degrees, and with no predators, they can reproduce prolifically, so officials want to know if there are more in the reservoir.

State parks officials have put up signs warning boaters to clean and check their boats for mussels, and officials may adopt emergency regulations to stop any further spread. About 3,000 boats are put in the reservoir on average summer weekends.

Colorado state parks officials Tuesday would not elaborate on what may be proposed.

The state parks board will vote on emergency regulations at a public meeting Friday in Colorado Springs at the Embassy Suites, ballroom section C, 7290 Commerce Center Drive. The meeting starts at 8 a.m. with a presentation on the mussel invasion. Public comment on what is proposed will be taken after 10 a.m.

CONTACT THE WRITER: 476-1605 or scott.rappold@gazette.com