Alien species

Alien species are introduced non-native species that have become established outside their normal habitat or native country.
The threat of marine invaders to biodiversity is second only to that of habitat loss.
There are currently about 65 marine alien species in Britain. Many species thrive in both salt and fresh water.
The main means of transport via boating is by attachment to the hull or propeller, or within bilge or engine cooling water.
Fast-growing species like zebra mussels are already causing problems in many areas. They can block engine cooling water intakes resulting in engines over-heating.

When recovering a trailer sailor boat or dinghy, drain water from every part of the boat and all equipment that can hold water.
Clean all parts of the boat, trailer and equipment that come into contact with the water before leaving the water catchment. Remove any visible plant, fish, animal matter and mud.
Dispose of any plant and animal materials found in a dustbin or skip.
For boats kept in the water permanently, hull fouling is the main means of transfer. Have your hull cleaned regularly to avoid the risk.
Do not run through water plants and weed if avoidable. If caught up on the hull or propeller they can be transferred to another area.
Risks of acquiring invasive hitchhikers on the boat increase the longer the boat is kept in the water. Consider only keeping the boat in the water when it is needed.

Report evidence of the invasive species to the Environment Agency; SEPA or CCW

Download our fact sheet on alien species

Find out about the All Choked up! Campaign

Identify common marine aliens - visit the Marine Life Information Network (MarLIN)
www.marlin.ac.uk/marine_aliens

Test your knowledge by taking the 'Exotic Invasion' quiz

Identify all species introduced to Britain since 1700 at www.introduced-species.co.uk