Invasive Zooplankton

Scientific Names: Oithona davisae and Pseudodiaptomus forbesi What Are They? O. davisae and P. forbesi are copepods (small aquatic crustaceans related to shrimp) that are native East Asia. O. davisae is about a half-millimeter long, and P. forbesi is about 1 millimeter long. Are They Here Yet? Yes, invasive zooplankton have been found in the […]

September 18, 2019
Marine Clams

Scientific names: Nuttallia obscurata and Potamocorbula/Corbula amurensis Featured image credit: User: pintail, Link to observation. What Are They? Nuttallia obscurata, commonly known as the purple varnish, or mahogany clam was first introduced to the United States and Washington from ship ballast water from Asia It is freshwater tolerant and is most abundant in areas […]

August 8, 2019
Mitten Crab

Scientific name: Eriocheir sinensis What Is It? A mitten crab is light brown to green, with brown hairy patches resembling mittens on its claws. It spends most of its life in freshwater, but reproduces in saltwater. A mitten crab can prey on and compete with many native aquatic species, posing a threat to ecosystems and […]

August 6, 2019
Vineyard Snail

Scientific name: Cernuella virgata What Is It? The vineyard snail (occasionally referred to as the Mediterranean white snail) is small (less than 1 inch across) and white or tan in color with dark brown spiral bands. These snails often are found on top of vegetation, particularly crops, where they can survive long periods of hot […]

August 5, 2019
European Green Crab

Scientific name: Carcinus maenas What Is It? The European green crab is a small shore crab that is not necessarily green like its name implies. It typically is found in high intertidal areas and marshes in coastal estuaries and wave-protected embayments. It can live on a variety of surfaces including sand, mudflats, shells, cobble, algae, […]

August 2, 2019
New Zealand Mud Snail

Scientific name: Potamopyrgus antipodarum What Is It? The New Zealand mud snail is a tiny (less than 6 millimeter) aquatic snail that is adaptable to diverse climates and environmental conditions. It is found in freshwater and brackish environments. Is It Here yet? Yes. New Zealand mud snails were first discovered in the lower Columbia River […]

August 2, 2019
Invasive Crayfish

Northern Crayfish (Orconectes virilis) and Red Swamp Crayfish (Procambarus clarkia) What Are They? Crayfish are freshwater crustaceans related to lobsters. In the Pacific Northwest, three species of invasive crayfish are present: northern, red swamp, and rusty. The northern crayfish is native to Montana, Wyoming, the upper Mississippi River, the Great Lakes, and the Hudson River. […]

August 2, 2019

Scientific names: Styela clava, didemnum vexillum, and ciona savignyi What Is It? Tunicate, commonly called a sea-squirt, is a primitive marine animal that spends most of its life attached to docks, rocks, or the undersides of boats. A tunicate is built like a barrel. The name “tunicate” comes from the firm, but flexible body covering, […]

August 2, 2019
Zebra and Quagga Mussels

Zebra mussels (dreissena polymorpha) and quagga mussels (dreissena bugenis) What Are They? Zebra and quagga mussels are freshwater mollusks that colonize lakes and rivers. Their preferred habitats include the calm waters upstream of dams. They are most abundant on hard, particularly rocky surfaces. Are They Here Yet? No, but they are only a day’s drive […]

August 2, 2019