Dispersal of invasive species by ballast water

[2] Typically, ballast water discharge contains a variety of biological materials including non-native, invasive, and exotic species that can cause extensive ecological and economic damage to aquatic ecosystems.

[citation needed] Dreissena polymorpha, commonly known as the zebra mussel, live in freshwater and are native to southern lakes in Russia and Ukraine.

In North America, Great Britain, Ireland, Italy, Spain, and Sweden, the species has invaded native habitats.

The mussels take oxygen and food from the water, limiting the resources available for native species and disrupting local ecosystems.

[4] Mnemiopsis leidyi, commonly known as the sea walnut, is a ctenophore species native to the eastern coast of North and South America.

For aquaculture and fishing industries, C. maenas poses a particular threat due to its appetite for valuable farmed mollusks.