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An Update on Aquatic Nuisance Species

Posted on: Wednesday, 11 April 2007, 18:00 CDT

While many outdoor writers champion the latest and greatest gadgets and technological advances that complement our outdoor experiences, I prefer to invest a good share of my time and attention in issues such as habitat, ethics and safety.

When I mention habitat, I suspect since ice-off on your favorite fishing water has either occurred or is at least worthy of serious anticipation, it's a good time to devote a column to aquatic habitat - specifically, the threats to what we enjoy in North Dakota today.

For this reason I bring an update in the tangled world of aquatic nuisance species, or non-native invaders into our aquatic ecosystem.

Aquatic nuisance species, or ANS, have become a buzzword over the past decade or so because they upset the balance of nature. These plants and animals have the potential to reduce our standard of outdoor recreation and cost us big money working to reduce or eliminate their presence.

A recent example is the discovery of quagga mussels in the Colorado River system, including Lakes Mead, Mohave and Havasu. This is the first evidence of this species in the West. Quagga are related to the notorious zebra mussels that have overrun the Great Lakes and Mississippi River watershed, can multiply rapidly, clog pipes and pumping machinery and ruin the ecology of lakes and reservoirs. This invasive mussel resulted in draining an aqueduct of more than 200 miles to hopefully stop from further spread.

Think of the money and resources needed for just this one effort. Prevention is a better option.

Perhaps a more concrete North Dakota example is carp in your favorite fishing hole. Carp were introduced into the Midwest, including North Dakota, more than 100 years ago, before people clearly understood the risks of introducing species into new environments. Carp compete with more desirable fish for food and space. Anglers place a priority on fisheries biologists to battle carp and other nuisance species where practical. This takes time, money and effort that could be spent elsewhere.

Here's a summary of a few other aquatic nuisance species that have already appeared in North Dakota. Many others are not far away.

3 Curly leaf pondweed has infested parts of Lake Audubon, Lake Sakakawea and the Missouri River. It uses nutrients that native aquatic plants need and can out-compete other plants for space, resulting in a monotypic and less diverse habitat for fish. Curly leaf pondweed produces heavy mats on the surface that are a nuisance for boaters and swimmers.

3 Eurasian water milfoil is still present in Dead Colt Creek Reservoir near Lisbon and the Sheyenne River near Valley City. The North Dakota Game and Fish Department has drawn down the water level in Dead Colt Creek by about 12 feet the past two winters in an attempt to freeze out Eurasian milfoil plants. It's a risky venture because, under the right conditions, a lower water level could lead to winterkill of one of the state's better bass fisheries.

On the other hand, if NDGFD doesn't try to keep the milfoil at bay, Dead Colt Creek could be a conduit for milfoil to other lakes and rivers in the state. It's a lot of cost and effort to control a problem brought in from somewhere else.

3 Salt cedar is a more recent problem along the Missouri River system not only in North Dakota, but extending up and down the entire drainage. Salt cedar displaces cottonwood along riparian areas and kills out grass and shrubs. Salt cedar roots suck up vast quantities of water, further draining areas like Lake Sakakawea. Tens of thousands of dollars have been spent on salt cedar control in recent years.

The bottom line is we all enjoy our time fishing, boating and otherwise enjoying our water-based recreation. We tend to take these opportunities for granted, and human nature has made us more reactive than proactive.

To maintain the health of our aquatic ecosystems means we need to take a different approach and begin seriously addressing potential transfer of aquatic nuisance species. It's a perfect example of the old cliche that says an ounce of prevention is worth a pound of cure. But in the case of ANS, once it's here, there really is no cure, just a continuing need for time and money to keep it from spreading even more.

Source: Bismarck Tribune

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