ballastvettä

Ballast water is water carried in ships to ensure stability and trim. Ships take on ballast water when they have a light load, such as when they are empty of cargo. This water is typically drawn from the sea at one location and discharged at another, often thousands of miles away.

The primary concern with ballast water is its potential to transport aquatic organisms. These organisms can include bacteria, microbes, and the eggs, larvae, and adults of various species, from plankton to fish. When ballast water is discharged in a new environment, these non-native species can become invasive. Invasive aquatic species can disrupt local ecosystems, outcompete native species for resources, and cause significant economic damage to industries such as fisheries and aquaculture.

To address this issue, international regulations have been developed. The International Convention for the Control and Management of Ships' Ballast Water and Sediments, adopted by the International Maritime Organization (IMO), entered into force in 2017. This convention requires ships to manage their ballast water to remove or kill harmful aquatic organisms and pathogens before they are discharged. Ships can achieve this through various methods, including ballast water treatment systems that filter or sterilize the water, or by performing mid-ocean exchange, where ballast water is pumped out and replaced with cleaner ocean water.