Aquatic Invasive Species

Aquatic invasive species are spread primarily through human activities. Awareness and education among anglers, boaters and other water recreation participants as well as water garden and aquarium hobbyists are vital to limit their spread.

Here are some examples:

Aquatic Invasive Animals

Zebra mussels (Dreissena polymorpha) and
Quagga mussels (Dreissena rostriformis bugensis)
These fresh water mussels colonize hard surfaces. They are highly efficient filter feeders, removing phytoplankton from the water and starving other water animals. This disrupts the food web in aquatic systems. Human health risks arise from concentration of contaminants in the mussels that increase in fish feeding on the mussels and in anglers consuming the fish. Economic costs come from clogging intake pipes of water and power facilities as well as damage to boat propellers, hulls and fouling infrastructure like locks and dams.

Zebra Mussels
National Invasive Species Information Center

Quagga Mussels
National Invasive Species Information Center

Northern Snakehead (Channa argus)
These predators can potentially devastate native fish and wildlife populations. Young snakeheads eat zooplankton, insect and fish larvae and small crustaceans. Frogs, fish, crustaceans, small reptiles even small birds and mammals are taken by adults. Nicknamed "frankenfish," they tolerate poor water conditions and can move over land for short distances. They are well established in the Potomac River.

Snakeheads: The Newest Aquatic Invader
National Invasive Species Information Center

Aquatic Invasive Plants

Purple looseatrife (Lythrum salicaria)
Purple loosestrife fact sheet

Didymo or Rock Snot (Didymosphenia geminata)
Didymo, a freshwater alga, is primarily spread by anglers, boaters and their equipment but can also be spread on clothing of children or pets wading in an infested stream. It grows in stream beds on rocks creating clumps of stalk material up to 8 inches deep that carpet the bottom, disrupting the stream ecology.

National Invasive Species Information Center

Hydrilla is a federal noxious weed that grows quickly, forms dense mats and interferes with navigation, irrigation and can clog hydroelectric water intakes. The dense mats prevent sunlight penetration, shading desirable plants growing underneath. Blooms of this plant that later die in a pond can consume all the oxygen, causing a fish kill. It slows the flow of water in streams and irrigation ditches and can be found in freshwater lakes, ponds, rivers, canals and impoundments.

USDA invasive species info
PA DCNR Invasive Plant Search

European Water Chestnut (Trapa natans)
Dense floating mats choke waterways, limiting nutrients, light and oxygen for native organisms. It produces sharp nuts that can puncture shoes causing painful wounds and floating mats make boating and swimming nearly impossible.

National Invasive Species Information Center

VHS (Viral Hemorrhagic Septicemia)

For information on aquatic invasive species and water gardens:

Aquatic Invasive Species & Water Gardens

For more information on aquatic invasive species:

Aquatic Nuisance Species (ANS) Task Force

Habitattitude

Pennsylvania Fish & Boat Commission Aquatic Invasive Species
Pennsylvania Sea Grant Aquatic Invasive Species
Protect Your Waters
USGS Nonindigenous Aquatic Species (NAS) Site

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