1. Zebra Mussel (Dreissena polymorpa) and Quagga Mussel (Dreissena polymorpha)

Zebra mussels are small freshwater mollusks named for the striped pattern of their shells.

Quagga mussels resemble the zebra mussel, but are generally rounder in shape with shells that appear asymmetrical when viewed from the front. They both have profound effects on the lakes they invade by disrupting food chains. Voracious filter feeders, they reduce the availability of food for larval and juvenile fishes meant for sport and commercial fisheries. They attach easily to boats, docks and buoys.

For more information, visit the 100th Meridian Web site and the USDA National Invasive Species Information Center.

• Quagga Mussel Fact Sheet (pdf)

2. Northern Snakehead (Channidae)

Photo courtesy Susan Trammell, Bugwood.org

Snakeheads are freshwater fish native to parts of Asia and Africa. Currently, they are not found in Oregon but if introduced would threaten native fish, the recreational fishing industry and aquatic ecosystems. Voracious predators, they feed on other fishes, crustaceans, frogs and small reptiles.

For more information, visit the USDA National Invasive Species Information Center.

3. Asian Carp or Silver Carp, Bighead Carp

Asian carp can grow quickly to over 50 pounds, directly competing with native fish for food and space. They consume phytoplankton, increasing algae, detrimentally affecting river systems and decreasing recreational opportunities. The species is native to China.

For more information, visit the USDA National Invasive Species Information Center.

4. Chinese Mitten Crab (Eriocheir sinensis)

Native to Asia, the mitten crab is identified by the patches of hair its white-tipped claws. It contributes to predation of native invertebrates and modifies stream banks through burrowing activities that cause bank erosion. It impacts freshwater food webs at many levels. For more information, visit the USDA National Invasive Species Information Center.

• Chinese Mitten Crab fact sheet (pdf)

5. New Zealand Mud Snail (Potomopyrgus antipodarum)

New Zealand Mudsnails are tiny snails (3-6 mm long) that have brown or black cone-shaped shells. As they reproduce quickly and mass in high densities, there is concern they will impact native invertebrates and the food chain of Oregon’s native trout and degrade steam water quality, with devastating effects to recreational fishing. They attach easily to boats, boots, waders and fishing gear. 

For more information, visit the USDA National Invasive Species Information Center Web site.

6. Rusty Crayfish (Orconectes rusticus) and Red Swamp Crayfish (Procambarus clarkii)

Rusty crayfish have robust claws and dark, rusty spots on each side.  Red swamp crayfish have spots covering their upper body and claws. They affect aquatic food webs by displacing native crayfish species, by destroying native plant beds and by burrowing into levees, dams, and water control structures. Both species are native to the eastern United States. 

For more information, visit the USDA National Invasive Species Information Web site.

7. Oriental Weatherfish (Misgurnus anguillicaudatus)

Oriental weatherfish have long, cylindrical, eel-like body and a mouth that is small, narrow and has six barbells. Potentially, weatherfish could impact native species by predation and competition for food and habitat.

For more information, visit the USGS Nonindigenous Aquatic Species Web site.

• Oriental weatherfish fact sheet (pdf)

8. Feral Swine or Wild Boar (Sus scrofa)

Feral swine are free-roaming pigs found on public or private land, i.e., they are not being held under domestic management confinement. They vary in size and coloration. Impact to Oregon: damage to habitat and depredation of livestock and wildlife as well as disease transmission to wildlife, livestock and humans. Read the Feral Swine Action Plan for Oregon on the Oregon Invasive Species Web site.

For more information, visit the USDA National Invasive Species InformationWeb site.

• Feral swine fact sheet (pdf)

9. Non native Turtles: Red Eared Slider (Trachemys scripta elegans) and Common Snapping Turtle (Chelydra serpentine)

Red-Eared Slider

The Red-Eared Slider is a turtle from the eastern U.S. It has a dark shell, yellow stripes on the neck and legs, and a bright red patch just behind the eye. As an invasive nonnative species in Oregon, they compete with native turtles for food and habitat, especially nesting sites. They can spread diseases to which Oregon’s native turtles have no immunity.

• Red-eared slider fact sheet (pdf)

Common Snapping Turtle

The common snapping turtle, indigenous to the eastern United States, can reach up to 18 inches in length. Its top shell is strongly serrated and varies from tan/brown to olive to almost black. Its long tail has three rows of saw-tooth keels.

It is illegal in the state to import, buy, sell, possess, transport, or release either of these non-native turtles and most other non-native water turtles. If you are in possession of a non-native turtle, contact your local ODFW office.

For more information on red eared sliders, visit the USGW Nonindigenous Aquatic Species Web site. For information on snapping turtles, visit the Michigan Department of Natural Resources Web site.

• Common snapping turtle fact sheet (pdf)
• Oregon’s native and nonnative turtles

10. American Bullfrog (Rana catesbeiana)

Bullfrogs, usually green mottled with brown, can grow to over 6 inches in length. Sold for aquariums, they have also been released into the wild as an edible frog. In Oregon, they impact water quality and prey upon many native turtles, frogs, fish and snakes. The bullfrog is native to central and eastern U.S. and southeastern Canada.

• Bullfrog Fact Sheet (pdf)