Exotic marine species are plants or animals, which have been either deliberately or unintentionally transported to the waters of a new state or another country. These foreign marine species include a variety of different animals and plants, such as fish, crabs, starfish and seaweed. Whilst many of these invaders are only minor ecological pollutants, some of them become serious pests and many also threaten Australia's marine ecosystem.
             Exotic marine species pose a threat to the ecosystem all over Australia. Many species have come from overseas, such as the European Carp and the Northern Pacific Seastar. All the waters around Australia are infested with foreign marine species. Once foreign specie is introduced, it rapidly repopulates, eventually spreading to other parts of the water not previously affected. This is why foreign marine species have become such a huge and significant problem.
             Thankfully, most of the marine animals and plants that establish themselves in foreign waters are relatively harmless. However, some invaders are the tough, aggressive types, which prey on native species. They battle with our native species for food and space, and alter the marine habitat to suit themselves. Current investigations have shown that one in every six introduced marine species will become an actual pest to the environment.
             As well as damaging the ecological system, introduced marine species can have the potential to damage fisheries and the shipping industry. Introduced species may dominate marine communities and wipe out all of the native species, some of which are the basis of large recreational and commercial fisheries. Exotic species seem to smother anything they come across, including organisms, and any other artificial structure in the water, such as vessels, jetties, stormwater pipes and long-lines commonly uses in aquaculture.
             Exotic marine species can be transported to foreign waters in many ways. Some of t...