Marine Invasive Non-Native Species
Status of marine non-natives: Stable with some concerns
(Baxter et al, 2011)
Status of marine non-natives: Stable situation since 2012
(United Kingdom Marine Monitoring & Assessment Strategy, n.d)
Non-native species (NNS) refers to species which are found beyond their native range. This can happen in terrestrial and marine environments. NNS are introduced to new areas through unintentional means, for example accidental or careless human behaviour, or intentionally, normally to seek economic gain from the species. NNS can cause damage to the native species, biodiversity, social, and economic aspects of an area once they become established. Once the NNS are aggressively thriving, to the detriment of native species, biodiversity or activities they are considered ‘invasive’ NNS (INNS). Classifying a species as NNS or INNS is specific to the site and species.
According to AquaNIS there are 147 species accounts of non-indigenous and cryptogenic marine species across Britain, including microbiota such as bacteria etc, as of January 2020. This is a high estimate as it includes microbiota. Alternatively, in 2015 the Scottish Environmental Protection Agency (SEPA) reported that at least 30 non-native plant and animal species have been found within inland and marine waters around the UK (Scottish Environment Protection Agency, 2015).
Although the exact number of NNS we have in the UK cannot be conclusively known, one thing is certain, the number of NNS is increasing. In the marine environment reasons for this increase include;
- lack of awareness of NNS and therefore spreading NNS unintentionally or giving the NNS species time to become established without control measures,
- the rising intensity of ocean use and travel,
- rising sea temperatures, providing a more hospitable environment for some NNS while also lowering the resilience of native species (see Climate Change – Impacts on Marine Life and Processes)
- careless or reckless behaviour.
Biosecurity measures are actions through which people can limit the risk of spreading NNS through good practice and preemptive measures.
As this review covers the Solway Firth coastal and marine area, freshwater species and associated plans do not fall within the scope of this section. However, it is worth noting that there are several biosecurity plans covering rivers entering the Solway. These include; Cumbria Freshwater Biosecurity Plan (2011 – 2015) which covers both fresh water and brackish water species, the River Nith Catchment biosecurity plan (2011-2016), River Annan Trust biosecurity plan (2010-2016).
The two biosecurity plans which cover the Solway are; North Western Inshore Fisheries and Conservation Authority (NWIFCA) Biosecurity plan 2014-2019 (although this plan covers the entire NWIFCA area), and Solway Firth Partnership Biosecurity Plan 2018-2021.
Although there are two biosecurity plans for the Solway Firth, INNS are discussed in several other plans which cover parts of the Firth. For example, the Solway Tweed River Basin Management Plan (2015 Update) and Managing Invasive Non-Native Species in Scotland’s Water environment: A Supplementary Plan to the River Basin Management Plans, Site Improvement Plan for the Solway Firth SAC and Upper Solway Flats & Marshes SPA, and NSA Management Strategies for Nith Estuary, Fleet Valley and East Stewartry Coast, to name a few.
Image; Japanese wireweed. © Solway Firth Partnership