Scientific Names: Oithona davisae and Pseudodiaptomus forbesi
What Are They?
These zooplankton (Oithona davisae and Pseudodiaptomus forbesi) are small copepods (crustaceans related to shrimp) native to East Asia.
Are They Here Yet?
Yes, invasive zooplankton are in the Columbia River and Salish Sea.
Why Should I Care?
Once established, eradication is impossible. They can replace native copepods, altering the food chain by reducing plankton-eating fish, such as salmon.
What Are Its Characteristics?
- O. davisae is about half a millimeter long; P. forbesi about 1 millimeter long.
How Can We Stop Them?
Ships spread these copepods when they take up ballast water (used for stabilization) in one part of the world, then release it and the copepods it contains, elsewhere. Exchanging ballast water before reaching a new port does not stop completely the spread of invasive species but when combined with treating ballast water, is the best way to prevent the spread of invasive copepods.