Non-Native Species and Biosecurity Planning


Non native marine species

As part of the Shetland Islands Regional Marine Plan (SIRMP) we are investigating the occurrence of introduced marine species (also known as marine aliens or non-native species) in Shetland. This will help to inform the Biosecurity Plan for the Shetland Islands.

Non-native species are plants and animals which originate elsewhere, e.g. Asia or America, but have been brought to the UK through man’s activities. Not all introduced species are problematic, but some species can impact upon the marine environment and upon our marine industries, such as aquaculture and fisheries.

There are now a number of Non-native species in Shetland which have been introduced to the marine environment in the UK, some of which have been here for several decades and have been slowly spreading around the coast, and some which have been introduced more recently. Although survey work has taken place around the Scottish mainland to establish the presence of introduced species, a specific non-native species survey had never been undertaken in Shetland. In 2012 we initiated a non-native species monitoring programme around the Shetland coast.

Non-Native Species

Several introduced species can cause problems for aquaculture and fisheries, including the Carpet Sea Squirt, which is also known by the less attractive name ‘marine vomit’. This species, which is originally from Japan, can be found on the south coast of England and in Ireland, where it has been causing problems for the shellfish industry by smothering oyster beds. It can also smother farmed mussels. This species has been found at Largs in the Firth of Clyde, Scotland, and in Holyhead marina, North Wales.

Another introduced species that has been causing problems in the UK is the algae Wireweed, which is spreading up the west coast of Scotland. It can become a nuisance in ports and marinas, and around beaches, as it grows rapidly, clogging waterways and fouling structures and boats.

As part of the project, we have developed leaflets for the aquaculture industry and marinas and marine users (see Downloads, below), which contain further information on several non-native species, and what you can do to limit their spread and impact on Shetland.

An Identification Guide: Marine Aliens & Climate Change Indicator Species is also available. This has a longer list of species to look out for; including some which, if found, may indicate the seas around Shetland are warming.

Getting Involved

Following ‘good practice’ can minimise spread of non-native species:

  • Keep boats and structures and free of fouling as possible.
  • Check for ‘invasives’ when moving equipment between different areas (e.g. boats)
  • Check, clean and dry personal gear when moving between areas.
  • Do not throw even small pieces of non-natives back into the water, as some can grow back from tiny bits.

If you spot any marine species that you think have been introduced you can contact the marine spatial planning team either by email, phone, or post. You can download an Introduced Species Recording Form. Please also take a picture if you can do so safely.

Good practice and a fast response can limit the spread of non-native species!


For more details, please contact Marine Spatial Planning staff:

Further Information

Related Links: