Common questions with important answers.


What is an invasive species?

An invasive species is a plant, animal or other organism that causes environmental, economic and/or human harm when introduced by humans into a new ecosystem from its native or original ecosystem.

Why is the OPA concerned about invasive species?

Invasive species can displace native species, degrade habitat and the quality of outdoor recreation, harm public and private property, threaten human health and safety, and impact recreation-based economies.

Zebra mussels can alter aquatic food chains by displacing native species. They can clog drinking water intake pipes located in the lakes and increase water supply maintenance and costs. Their empty shells can accumulate and cover shorelines and be a hazard for walking with bare feet. Silver carp can be dangerous to boaters. Boat noise triggers their nervous system, causing them to jump high out of the water and potentially hit water skiers or boat passengers. Eurasian watermilfoil, an aquatic plant, can grow so aggressively it forms thick mats that can entangle boat props.

How do species become introduced from their native into new habitats?

The rate of species introductions has increased dramatically in the past few centuries, as a result of human activities, such as global exploration, trade, and colonization.  Species evolve and disperse naturally, but at a much slower rate without human influence.

Species introduction happens both intentionally and unintentionally. In the late 1800s Federal funding helped to introduce carp  to the United States from Europe for their presumed culinary excellence and angling potential. By contrast, ocean going vessels from Europe accidentally introduced the zebra mussel to North America by dumping contaminated ballast water into the Great Lakes.

More recently, zerba mussels have dispersed into inland lakes, largely through the inter-lake movement of recreational and fishing boats.  Mussels attach to boats, nets, docks, swim platforms, boat lifts, and can be moved on any of these objects. They also can attach to aquatic plants, making it critical to remove all aquatic vegetation before leaving a lake. Microscopic mussel larvae may be carried in water contained in bait buckets, bilges or any other water moved from an infested lake or river. Click here to learn more.

 Do all introduced species become invasive?

Only about 1 percent of all introduced species become invasive. Often a lack of predators and disease allow an introduced species to grow uncontrollably.

What has the OPA done to help prevent the spread of invasive species?

  • Education: The OPA has been educating the public about the threat of Eurasian watermilfoil, zebra mussels, silver carp and other invasive species since the 1990s to prevent their spread. Because fishing tournaments and sailboat races often bring boats from other lakes with known or potential invasive species infestations, the OPA targets these audiences for education through the media.
  • Legislation The OPA encouraged the passage of legislation making the transport of aquatic invasive species illegal and punishable by fine. Prior to this, law enforcement officials did not have any authority to remove invasive species if discovered on a boat trailer or prop or to fine the carrier.
  • Electric Fish Barrier and Silver Carp: The OPA championed fundraising efforts for the electric fish barrier at the Lower Gar Outlet of the Iowa Great Lakes by raising $700,000 for the project.
  • Boat ramp inspection and education: Since 2010 the OPA has cost shared extra Iowa Department of Natural Resources staff to monitor 12 boat ramps in the Iowa Great Lakes.

What can I do to prevent the spread of invasive species?

Follow the Iowa Department of Natural Resources guidelines. Clean your outdoor recreation gear to prevent the introduction and spread of invasive species. Do not release an unwanted pet or fish into the wild. Garden with native species. Learn which invasive plants threaten the ecosystems in your area, and control invasive plants on your property.