Marine Research Findings of the VECTORS Project

This website provides access to the research results of the VECTORS project, which can be used to support marine management decisions, policies and governance as well as future research and investment. VECTORS was a large scale project that brought together more than 200 expert researchers from 16 different countries. It examined the significant changes taking place in European seas, their causes, and the impacts they will have on society.

Ecosystem impacts of non-indigenous species in the Baltic Sea

Invasion of non-indigenous species is acknowledged as one of the most important external drivers affecting structure and functions of marine ecosystems globally. This paper offers literature based analysis on the ecological effects of the widespread (occurring in at least 50% of countries) and currently established NIS on ecosystem features in the Baltic Sea. In total, 18 widespread non-native taxa were included into analysis.


Our current understanding on both the direction and magnitude of the effects of even the most widespread NIS on the structure and dynamics of the Baltic Sea ecosystems is very limited.

Out of the 18 NIS taxa studied, there are no published records on 28% of NIS for any of the seven impact categories investigated. When ecological impacts are known, laboratory experimental evidence dominates over field studies. Combined observations on impact strength, information type and confidence level suggest that the two benthic invertebrates, the polychaete Marenzelleria spp. and the zebra mussel Dreissena polymorpha exert the highest ecosystem impact. Despite continuously accumulating information on the NIS effects, however, the confidence of findings is still low.

Relevance for Policy:
  • Alien Invasive Species Directive
  • Convention on Biological Diversity
  • EU Biodiversity Strategy
  • Marine Strategy Framework Directive
Data availability:

Data used: This was a desk study, all data from published literature


Lead Author:

Henn Ojaveer
Estonian Marine Institute (EMI-UT)
Date of research: October 2014

Related articles:

Ecological impact of a non-indigenous cladoceran 

Impact of invasive mussels on carbon flow 

Invasive ecosystem engineers and biodiversity

Non-indigenous and invasive alien species

Vital rates of fish larvae 

Food web change along a nearshore-offshore gradient

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The content of this website may be subject to copyright, if you wish to use any of the information or figures please contact the attributed author(s).
This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 266445
© Vectors 2015. Coordinated by Plymouth Marine Laboratory.