Aggressive boat inspection keeps lakes mussel-free

As of Aug. 24, Boyd Lake was still clean. Same for Carter Lake and Horsetooth Reservoir.

Aggressive vessel inspection programs this summer at Northern Colorado’s three biggest and most popular boating destinations have so far prevented the spread of some very nasty little aquatic pests.

Zebra and quagga mussels have been spreading in bodies of water across the nation over the last 20 years, beginning when a Russian cargo ship from the Caspian Sea dumped its ballast tanks in the Great Lakes. The ballast contained the clam-shaped mussels that spawn exponentially and hitch rides on pleasure boats from one body of water to the next.

The invasive mussels out-eat and out-reproduce all competition, killing off native fish populations. Their vast numbers create problems for boaters as they clog and damage motors and cause expensive maintenance issues at dams and water treatment plants.

The first Colorado infestation was found at Pueblo Reservoir – a year-round boating destination – in January 2008. Colorado wildlife agencies scrambled to put together a statewide boat inspection program that resulted in the identification of seven bodies of water containing zebra and quagga mussel larvae by the end of the 2008 boating season.

Boyd Lake, a state park near Loveland, was inspected last year but no evidence of infestation was found. The Colorado Division of Wildlife is responsible for inspections in this year’s program, which now also includes Horsetooth Reservoir and Carter Lake.

Gene Seagle, invasive species coordinator for Colorado State Parks, said Boyd Lake remains clean. That may have something to do with the stepped-up inspection of boats before and after they spend the day in the water.

“Last year in state parks we did about 114,000 inspections,” Seagle said. “This year we’re looking at more than 200,000.”

Dan Rieves, visitor services manager for the Larimer County Department of Natural Resources, said inspections at Horsetooth and Carter have so far turned up clean.

“We have actually had a dozen or so high-risk inspections and a handful of boats qualified for decontamination,” he said. “One boat had an adult zebra mussel attached to it but it was dried out. But so far Carter Lake and Horsetooth have both tested negative for presence of mussels.”

Seagle said containing the spread of the mussels won’t be easy. “They’re an invasive species that sticks to boats and that’s a big problem,” he said. “But the real problem comes when they reproduce. Under good conditions it’s phenomenal, with a female producing a million eggs for each spawn. You have billions of young and in good conditions you can have exponential growth and lake bottoms being covered with these things.”

But it’s not just the biological impact that has wildlife and water officials worried. The mussels attach themselves to everything and can clog water pipes and water treatment plants, impeding water delivery to homes and agricultural users.

And it’s not just the adult mussels that are worrisome. Young larval mussels – called velligers – can get into boat engine cooling systems, live bait wells and other vessel spaces and survive until the boat reenters the water. That’s why inspectors are reminding boaters to thoroughly clean, drain and dry their vessels between every use.

Boat inspections in Northern Colorado will continue through the end of the season, which usually comes around the beginning of October.

So while things are still looking good in Northern Colorado waters, all four of Northern Colorado Water Conservancy District’s Colorado-Big Thompson reservoirs on the Western Slope – Lake Granby, Grand Lake, Shadow Mountain Reservoir and Willow Creek Reservoir – have tested positive for velliger mussels.

Yes, the same reservoirs that send water to Horsetooth and Carter through the C-BT system.

Talk about trying to keep your finger in the dam.

Steve Porter covers agribusiness for the Northern Colorado Business Report. He can be reached at 970-221-5400, ext. 225 or at sporter@ncbr.com.

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