Ships need ballast water for their safety, stability and manoeuvrability. In this manner, vast volumes of water can be transported between different continents. However, this water is not pure, but it contains a sample of the local ecosystem at the place of intake. At the port of destination, ballast water is pumped overboard again with the living and dead organisms it still contains. The receiving ecosystem is not always well adapted to the reception of newly introduced and previously unknown species. Because of this, they may cause harm to the local ecosystem, human health and the economies.
In order to reduce the risk of new introductions of non-indigenous species, the UN International Maritime Organization (IMO) has adopted the International Convention for the Control and Management of Ship’s Ballast Water and Sediments in 2004, This is called the Ballast Water Management Convention (BWMC). The official aim of the BWMC is ‘to continue the development of safer and more effective Ballast Water Management options that will result in continued prevention, minimization and ultimate elimination of the transfer of harmful aquatic organisms and pathogens’.