What Do Quagga Mussels, Pythons, and Hydrilla Have in Common?   

Posted on August 11, 2016
They’re all aquatic invasive species—and federal agencies are trying to do something about them. When nonnative plants, animals, and microorganisms live in new aquatic habitats, they can damage ecosystems and threaten commercial, agricultural, and recreational activities. Today’s WatchBlog explores what federal agencies are doing to address invasive species in U.S. waters. How did they get here? Aquatic invasive species can be found in all U.S. states and territories. There are several common pathways for them to enter aquatic habitats and travel to others, such as:
  • Trade—People can buy organisms, especially food animals and plants, and send them along trade routes or through the mail.
  • Ballast water—Ships take on water to improve their stability, but organisms can travel in that water.
  • Boats and boat trailers—Hauling a boat over land can help the organisms on it travel between unconnected bodies of water.
  • Aquarium release—Organisms can escape or be released from aquariums or aquaculture farms. 
  • Intentional introduction—People may illegally introduce organisms to bodies of water to improve sport fishing or increase stocks of live food sources.
For example, Chinese mitten crabs are native to the Pacific Coasts of China and Korea. They were introduced to California, the Great Lakes, and the mid-Atlantic coast by hitchhiking on ships and being discharged through the ships’ ballast water. Such crabs can also be purchased as food and sent through trade or mail routes. Once introduced, aquatic invasive species often spread to other locations and ecosystems, as shown in our report. To use the interactive features of this graphic, download the report PDF and find it on page 8. You can roll your cursor over each species to see where they are, and over the pathways for more detailed descriptions of how they work.

Excerpt from interactive graphic (Excerpted from interactive graphic in GAO-16-49.)

What are agencies doing about them?   A 1990 law created an Aquatic Nuisance Species Task Force to coordinate federal and state efforts. From fiscal years 2012 through 2014, the 13 federal task force member agencies estimated spending an average of $260 million annually on aquatic invasive species-related activities, such as: Quagga mussels covering infrastructurePrevention The U.S. Fish and Wildlife Service installed signs at National Wildlife Refuges to alert boaters to the risks of quagga mussels, and funded training across 18 western states on inspecting watercraft to identify and remove the mussels. Early detection and rapid response Environmental DNA can detect Burmese pythonsU.S. Geological Survey researchers tested water from the Loxahatchee National Wildlife Refuge in Florida for environmental DNA to determine whether Burmese Pythons had spread to the refuge. The South Florida environment camouflages Burmese Pythons so well that the chances of actually seeing one in the wild are slim. Environmental DNA is a relatively new tool that could help researchers “see” these hidden snakes.   Collection of Hydrilla for chemical researchResearch The U.S. Army Corps of Engineers is researching Hydrilla, a submerged invasive plant that has clogged navigation channels and other water systems across the United States. The researchers hope that a study of Hydrilla’s biology will help them develop a better understanding of its invasion into northern rivers and glacial lakes. There are more examples of agency activities to combat invasive aquatic species in our report. You can also check out our recommendation for keeping the task force on track.
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