Watch video: Invasive species
It's a surprising fact that one of the biggest polluters of the marine environment is ... water.
Ships load water for balance and stability when cargo levels are low, and then release the water when they pick up new cargo at another port. Some 10 billion tonnes of this ballast water is transferred around the world each year.
Ballast water is loaded with thousands of marine species, including plankton, algae, fish, jellyfish, and other invertebrates.
Most of the stowaways are not able to survive in their new environment when released from the ship. But some can - and only too well. These aliens can become invasive, rapidly out-competing local fauna or flora. They can alter the entire local ecology, leading to the collapse of fisheries and threatening endangered species. Exotic algal species can also pose a risk to human health by contaminating seafood.
Indeed, alien invasive species can be as damaging as oil spills, and their effects much more persistent.
Find out what WWF is doing!
Ballast water is loaded with thousands of marine species, including plankton, algae, fish, jellyfish, and other invertebrates.
Most of the stowaways are not able to survive in their new environment when released from the ship. But some can - and only too well. These aliens can become invasive, rapidly out-competing local fauna or flora. They can alter the entire local ecology, leading to the collapse of fisheries and threatening endangered species. Exotic algal species can also pose a risk to human health by contaminating seafood.
Indeed, alien invasive species can be as damaging as oil spills, and their effects much more persistent.
Find out what WWF is doing!
