Marine Invasive Non Native Species

Invasive non-native species, known as INNS, have increasingly become an issue both nationally and locally. These are species which have been intentionally or accidentally released into an environment outside their native geographic range. The relatively recent globalisation in the trade and tourism industries has allowed species to travel vast distances to new habitats where they can become ‘invasive alien species’. These invasive species can displace native plants and animals as a result of competition for space, light or food or may prey on local wildlife.

Invasive marine species can be transported in several ways but the most significant method is through shipping by attachment to hulls and in ballast water. The results can be significant, not only in terms of ecological impact but also economically as aquaculture and fisheries can be adversely affected. It can be very expensive to control and eradicate INNS once they become established and therefore more cost effective to concentrate efforts to prevent their arrival where possible.

The Check – Clean – Dry Campaign is being promoted by the government and recreational water users to try and Stop the Spread of aquatic invasive species.  The poster highlights good practice for water users.

Stop the Spread

The presence of INNS can also impact on the water environment and the condition of European Marine Sites, increasing the risk that these sites do not meet their favourable conservation target or the requirements of the Water Framework Directive.

The Government’s approach to invasive non-native species is guided by the internationally recognised 3-stage hierarchical approach as advocated by the Wildlife and Countryside Act 1981, as amended, and the 2012 Code of Practice in Non-Native and Invasive Non-Native Species:

Prevention – most effective and least environmentally damaging

Rapid Response – early detection and surveillance, potential eradication

Control & Containment – where the INNS is widespread and eradication is not feasible, control of the population and mitigation against negative impacts

Based on this ideal, Solway Firth Partnership continues to work towards establishing a framework for identifying sites of existing INNS, reducing the risk of the introduction of new INNS and managing existing key priority INNS in the Solway Firth. A Biosecurity Plan for the Solway  was produced in 2013 which highlighted the issues and identified actions.  One of those was production of a waterproof identification guide for use by boat owners, fishers and members of the public. You can request a copy from or call 01387 702162. Or you can download a copy here.

Marine INNS ID Guide

The biosecurity plan has been reviewed for 2021 – 24 and is now available, click here to download a copy or click on the image below.  It has been reviewed regularly from 2015 – 18. Previous copies are available (click here for a copy of the 2015 – 18) and for 2018 – 21 (click here for a copy).


Monitoring of Stranraer Marina and Harbour took place in summer 2016 to see whether marine INNS could be detected on settlement panels.  The results can be accessed in the report ‘Early detection of marine INNS using submerged settlement panels Stranraer Marina and Harbour, May to August 2016’ by clicking here.  This monitoring was followed up with a Rapid Assessment Survey which took place in Stranraer Marina in September 2016.  The results of that survey can be downloaded by clicking here

Studies on marine INNS have also been conducted in Stranraer Marina and Portpatrick Harbour in 2017, 2018 ,2019 , 2021 , 2022 , and 2023

Settlement panels were placed in Kirkcudbright Marina for the first time over the summer of 2019. This was not repeated in subsequent years as the tidal stream was too fast to support colonisation.

Settlement panels were placed in Maryport Marina for the first time over the summer of 2018 , then in 2019, 2021, 2022, and 2023

Settlement panels were placed in Whitehaven Marina for the first time over the summer of 2021 and then again in 2022, and 2023

The video below shows one of the monitoring panels placed and recovered at Stranraer in 2019. The video shows small moving creatures on the panel, these are the INNS Japanese skeleton shrimp Caprella mutica.


It was not possible to carry out any monitoring for marine INNS in 2020 due to COVID-19. It is hoped that it will be possible to continue monitoring in 2021.


It is now easier than ever for anyone to provide useful biological records of non-native species. Non-native species records help us to understand how many of these species are present in Britain, and the rate at which they are spreading.

You can record any non-native species online through iRecord, a site for managing and sharing your wildlife records. Please include a photograph of your sighting if you have one to help with identification.