Mechanism of introduction
Sediment in the bottom of a ballast tank provides a good habitat for transporting animals (left), these can then be deposited thousands of miles away when the ballast water is discharged (right). © Stephen Gollasch, GoConsult
Like many other invasive aquatic animals, Chinese mitten crabs have been introduced into new regions far away from their native habitat after being transported in ships’ ballast tanks.
How does this happen?
Ballast tanks are used to store water to ensure a vessel’s stability. Animals can be accidentally drawn into the vast tanks during water uptake in one port, and later deposited thousands of miles away when the water is discharged.
Ballast water and sediment control
Recognising this transport of foreign species as a problem, the International Maritme Organisation (IMO) - the UN body that deals with shipping issues - has set out standards for the control and management of ships’ ballast water and sediments.
Visit the IMO website to find out more about ballast water managementThe Bremen ballast water treatment project aims to develop a marketable ballast water treatment system that meets these standards.
Visit the Bremen ballast water treatment project website for more information