DENTRY: Mussels spur inspections

By Ed Dentry, Rocky Mountain News (Contact)

Published February 26, 2008 at 12:45 a.m.

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Photo by U.S. Geological Survey

Zebra mussels have spread to Pueblo Reservoir, prompting countermeasures.

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If you think summer boat ramp lines are long now at Colorado's busiest state parks, maybe you haven't seen anything yet.

Boats launching and leaving from state parks will be standing inspection this year in hopes of slowing the advance of invasive zebra mussels.

The destructive mollusks - natives of southeastern Russia - made their unwelcome Colorado debut last autumn at Pueblo Reservoir when Division of Wildlife researchers found three zebra mussels and their microscopic larvae.

The extent of the infestation isn't known yet, but its spread is virtually a given. The State Parks Board authorized the boat inspections knowing that zebra mussels are prolific and capable marine hitchhikers.

State Parks announced Friday that all watercraft and boat trailers will be subject to mandatory inspections, starting in March at Lake Pueblo State Park.

As waters warm, the inspections will extend to Cherry Creek, Chatfield, John Martin and Navajo state parks, which are considered to be at high risk for zebra mussel introduction.

Boats that fail inspections or whose owners refuse to allow the inspections could be denied access or quarantined.

To slow the spread of the mussels - and to speed passage through mussel customs - skippers are urged to keep hulls clean, drain live wells and lower engine units, let everything dry out between trips and regularly inspect for foreign matter.

State Parks hasn't worked out the drill for the inspections yet. The details will depend on budgeting for the project.

"Mostly we'll be relying on people to help us out in terms of being aware and not taking out without making sure the boat is pretty clean," State Parks spokeswoman Clare Sinacori said.

She said park rangers will do their best to keep delays to a minimum.

"Obviously, we're going to try to minimize impact," Sinacori said. "We're sensitive to the fact that there are busy times at the popular parks on the weekends."

She said the inspections probably will be spot checks. Parks officials also have discussed not allowing trailered boats to moor overnight, which would minimize their exposure to the pests.

The brown-striped mussels - averaging about the size of a fingernail - are the same as those that have been wreaking havoc in the Great Lakes and Mississippi drainage since they arrived in the ballast tanks of ocean-going vessels in the late 1980s.

Huge colonies of the tenacious mussels have clogged water conduits, creating expensive problems at dams, power generators and water treatment plants.

The critters also can damage boat engines by blocking off the flow of engine-cooling water.

At their worst, zebra mussels can cause severe environmental damage. Every adult zebra mussel filters one liter of water per day as it feeds on algae and plankton.

Infestations can render a lake clear and nearly sterile after the critters have ripped the foundation from under the aquatic food chain.

There's the rub for fish and fishing. Diminished plankton results in underfed juvenile sport fish. Plankton-eating gizzard shad, which every game fish eats, also will suffer.

A Google voyage through the world of zebra mussels offers one tiny bright spot to anglers. It seems that crayfish feed voraciously on immature zebra mussels.

The resulting crayfish boom, at least for now, has increased the commercial catch of yellow perch five-fold in Lake St. Clair, Mich. The crayfish abundance also has improved Great Lakes smallmouth bass fishing.

In the end, though, healthy plankton is the key to everything. It won't hurt to scrub the boat anyway.

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