Zebra mussel found at Geist means trouble

Indiana DNR Release:

A marina worker at Geist Reservoir hooked a Chinese mystery snail, an exotic species already prominent in the reservoir, while fishing recently, and on it was another undesirable species—an adult zebra mussel.

“That’s one invasive species colonizing on another,” said Doug Keller, aquatic invasive species coordinator with the DNR Division of Fish and Wildlife.

The find could signal trouble for Geist, much as the mussel's presence has affected other waters.

Previously found in more than 65 bodies of water in 44 counties throughout Indiana, the discovery marks the first time that the mussel has been found in the Indianapolis area. Zebra mussels were also discovered last year in Summit Lake, the first population known to occur in Henry County.

Keller said the effect of zebra mussels can be devastating where the invasive species successfully colonizes.

“Zebra mussels can rapidly multiply and are known for clogging drainage and filtration pipes,” Keller said. “Besides pipes, they can attach to virtually anything in the water column, including rocks, limbs, piers or even boats.”

Geist is one of three water supply reservoirs for the Indianapolis area. Keller said that as zebra mussel numbers increase in Geist and downstream in Fall Creek, there could be negative impacts to the water utility’s withdraw capacity.

Zebra mussels are originally from Europe and spread rapidly across North America in the 1990s. Aside from being a costly nuisance to humans, zebra mussels may also cause declines in fish populations. By filtering tiny plants, called phytoplankton, out of the water column, zebra mussels diminish the base of the food chain, potentially causing declines in all other aquatic life, including fish.

Keller said that few options for eradicating the mussel exist, short of eliminating every other living thing in the reservoir. The best means of control, he said, is by educating boaters about preventing further spread of the mussel.

Typically, zebra mussels are transported by human recreational activities such as boating or fishing. A few simple steps can prevent the spread of zebra mussels and other invasive species. Removing all aquatic vegetation and draining livewells, bilge, water lines and boat trailers at access ramps will prevent transport of the mollusk to other waters. Drying equipment after each use also is important.

“Letting all equipment dry for five days after a boating trip will prevent the spread of both adults and larvae," Keller said. “However, if you plan to visit a body of water sooner, you can use a solution of 5 percent bleach and water to clean and disinfect all of your equipment.”

For more information, visit http://www.in.gov/dnr/fishwild/3123.htm, or contact Keller at (317) 234-3883.