Aquatic Invasive Species

Aquatic Invasive Species (AIS) are species that enter into new ecosystems and spread, causing damage to native species and their habitants. These species are spread beyond their normal distribution, often as a result of human activities, and can threaten valuable environmental, agricultural or personal resources by the damage they cause.
They are spread a number of different ways (often referred to as vectors or pathways). One of the most important of the pathways is on boat hulls and in ballast or bilge water. On any one day, an estimated 3,000 species are transported in the ballast water of ocean-going vessels around the world.


Once established, Aquatic Invasive Species can spread and become a pest, making them difficult to get rid of. They are often non-native, but there are native invasive species as well. Every decade, some 15 aquatic species establish themselves in our coastal or inland waters. In the absence of their natural predators, the most aggressive of them spread rapidly and are then classified as invasive.


Aquatic Invasive Species will often out-compete, prey upon, or smother native species. They are one of the leading threats to biodiversity, including species at risk, as they reduce or destroy ecosystem functions and fish habitat. They also out-compete native populations for food and space, alter established food webs, possibly interbreed with native species, changing the gene pool, as well as introduce new diseases and parasites.

They can dramatically increase the operating costs of boat operators and port owners. They cost millions of dollars to control, and cause substantial revenue losses for local fisheries.