Non-indigenous species (NIS) are those species introduced outside their natural past or present range which might survive and reproduce. Some of the NIS can be harmless, with negligible impacts on native species. Other NIS can be invasive with potential to change native community composition and cause local population extinction with long lasting impacts which threaten biodiversity and ecosystem services. Those are addressed by the EU Regulation 1143/2014 on Invasive Alien Species which starts to include some marine species.

In relation to 'Non-indigenous species', the Marine Strategy Framework Directive considers that 'good environmental status' is achieved when 'Non-indigenous species introduced by human activities are at levels that do not adversely alter the ecosystems.

Descriptor 2: Non-indigenous Species do not adversely alter the ecosystem
Non-indigenous species introduced by human activities are at levels that do not adversely alter the ecosystems

The MSFD requires to identify the newly-introduced NIS in the EU Member States waters, as well as to assess the abundance and spatial distribution of established NIS, as well as the adverse effects produced by them.

Until 2020, at least 804 NIS (excluding microalgae and parasite/pathogen species) have been recorded in European marine waters, of which 640 have invaded since 1970. The vast majority are invertebrates (64.2%), followed by primary producers (18.4%) and vertebrates (17.3%). The proportion of each type of NIS and their annual rates of introduction vary among regional and subregional seas. The increase in the number of NIS at European level in recent years has been largely driven by introductions in the Mediterranean Sea and the North-East Atlantic, with an average of 14.0 and 11.7 new NIS per year between 2012-2017.

The transfer of NIS by seafaring vessels (transport-stowaway by hull fouling, ballast water and other) remains the main pathway of NIS dispersal, accounting for 46.6% of new introductions in European waters. This is followed by unaided introductions from neighbouring non-EU waters (22.8%), transport-contaminant, e.g. unintentional movement of live organisms (11.9%) and release in nature, i.e., intentional release (4.3%). Overall, the proportional increase in new introductions has risen over the last two six-year assessment periods for most of the pathway modes, most noticeably by hull fouling and escape from confinement, e.g., from aquaria, aquaculture and mariculture. These findings could be explained by increased scientific interest and effort to identify new NIS in hot spot areas such as ports and marinas (Azevedo, 2019; Tempesti et al., 2020). Nonetheless, they highlight that further action is needed to minimise future risks of new introductions and spread of invasive NIS and more knowledge on their impacts on biodiversity and ecosystems, in particular in a changing climate. For this it is crucial to have updated and validated NIS inventories, including baselines and threshold values so that policy implementation progress can be effectively monitored.

Outcomes from the MSFD assessments

In 2018, Member States had to update the Good Environmental Status (GES) assessments performed under Marine Strategy Framework Directive Article 8. The present dashboard displays the overall status reported by countries for the features, where the results show which is the percentage of assessments where GES has been achieved, not achieved or is unknown or not assessed.


  1. EC, 2008. Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008 establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive) (Text with EEA relevance), Directive - 2008/56 - EN - EUR-Lex (
  2. EC, 2017. Commission Directive (EU) 2017/845 of 17 May 2017 amending Directive 2008/56/EC of the European Parliament and of the Council as regards the indicative lists of elements to be taken into account for the preparation of marine strategies (Text with EEA relevance),
  3. EEA, 2023, Indicator: Marine non-indigenous species in Europe’s seas,
    a b