Destructive Zebra Mussels Threaten Our Waterways

Al Hanners is a retired oil geologist who worked worldwide for a major U.S. oil company for nearly four decades. He worked in the Middle East for the company in the early 1970s.

If you’re concerned by the effects of phosphorous and mercury in our waterways, how about zebra mussels? It’s not a matter of whether they will be here, but when. Consider the evidence in the excerpts below from an article by Richard Hanners, published in the Whitefish Pilot, a Whitefish, Montana, newspaper.

“Zebra mussels are dime-sized, black-and-white striped mollusks native to Eurasia. Believed to have hitched a ride in the ballast of an ocean-going cargo ship, they were discovered in the Great Lakes in 1988. Like most successful nonnative species, zebra mussels can easily slip into a pristine environment and, absent any predators, run rampant—creating havoc, death and destruction to the ecosystems. In the Great Lakes and Mississippi River area, zebra mussels have literally coated lake bottoms and ship hulls while suffocating native mollusks or crustaceans.

“Zebra mussels are aquatic hitchhikers. They can survive long periods of time as larvae found in residual water in a boat, or as adults attached to the boat. Once they infest a system, there is no feasible alternative to stop their progress. Zebra mussels are found throughout boats—including deep within the engine’s cooling system—so a thorough inspection and cleaning is essential. With vacationing fishermen hauling boats across the nation, it’s only a matter of time before one of the tiny bivalves is introduced here—immature zebra mussels are the size of a sesame seed, and they can clam up and survive without water or days or even weeks at a time.

“Zebra mussels are capable of spreading quickly until they dominate whatever water system they are brought to. With adult females producing 30,000 to 1.5 million eggs per year, zebra mussel populations can reach upwards of 30,000 individuals per square meter. In Lake Erie, 10-inch thick layers were found in rocky areas. They could virtually provide a carpet layer over important lake spawning beds.

“They spend their entire adult life filter feeding the zooplankton and phytoplankton from the water. It is estimated that during their peak numbers in Lake Erie, they filter the entire lake every day.

“Zebra mussels prefer to colonize rocky areas or man-made structures, such as docks and intake or outlet pipes for cities and industry. (In Lake Whatcom, the city’s water intake pipe could become clogged with the tiny mussels.)

“With huge volumes of water filtering through them, zebra mussels can bio-accumulate dangerous man-made pollutants that come from urban area runoff, exhaust from motorized watercraft and wood smoke. Zebra mussels can accumulate the toxins in their fatty tissue and then release concentrated amounts into the system through their feces or to other species if eaten.”

“All it would take to start an infestation of zebra mussels would be one boat contaminated with them. Sooner or later that is likely to happen. Education of the public is needed, but that would not be enough. We need to keep an account of land movement of watercraft and to get fishing clubs to support the policy. We should require inspection of boats that have been out of the state in the last 12 months. The problem is lack of enforcement because of other priorities. Law enforcement agencies are strapped by lack of adequate funds and too often even warrants for lawbreakers are not pursued because of lack of funds.

“However, we could require registration of boats and declaration at that time whether or not a boat had been out of Washington state in the last 12 months. There should be hefty fines for boat owners who brought boats into Washington state and did not have them inspected and cleaned. There should be spot checks now and a total review and charges if and when zebra mussels appear here. That should discourage carelessness by boat owners.” §