Is it Alien to you…. Share it!!!

iSea aims to monitor the expansion and establishment of marine alien species in Greece and neighbouring countries in the Eastern Mediterranean, in particular Cyprus. The project is based on observations sent by non-experts that spend their time at the sea. Currently the project has a research permit from the Greek Ministry of Environment to collect specimens of alien species in order to study their biology and ecology.

What we have achieved so far …

The observations map

The map is updated on a monthly basis

How to contribute?

  1. Become a member by joining the project's Facebook Group. Post your observations of marine alien species and comment and discuss other member's findings!
  2. Send us your observations via
  1. Inform the people around you, where to report their observations
  2. Become a member of our research team by sending your CV at

What are the alien species;

  • Alien species: any live specimen of a species, subspecies or lower taxon of animals, plants, fungi or microorganisms [that does not natively belong to the ecosystem/ecological niche it has been found in??]
  • Introduced species: is any species outside its natural range [but that has been purposefully / intentionally inserted into a new ecosystem?]
  • Invasive alien species: is an alien species whose appearance and proliferation in an ecosystem has been found to threaten or adversely impact upon biodiversity and related ecosystem function.
  • Invasive alien species of Union concern: is an invasive alien species whose adverse impact has been deemed such as to require concerted action at Union level
  • Invasive alien species of Member State concern:is an invasive alien species other than an invasive alien species of Union concern, for which a Member State considers on the basis of scientific evidence that the adverse impact of its release and spread, even where not fully ascertained, is of significance for its territory, or part of it, and requires action at the level of that Member State
  • Lessepsianmigrants: marine species migrating across the Suez Canal, usually from the Red Sea to the Mediterranean Sea, and more rarely in the opposite direction.

Problems caused by invasive species

More than 1000 marine alien species have been recorded in the Mediterranean Sea with more than 300 found in Greece. A number of these are considered invasive causing ecological damage such as displacement of indigenous species, loss of genotypes, alteration of the structure of indigenous communities, change of food webs etc. Equally, they have a significant impact on local economies in regons throughout Greece as they affect fishing catches and tourism. The European Commision has estimated the economic impact of invasive species at 12 billion euros per year. Lastly, some species are a direct threat to people such as, Lagocephalus sceleratuswhich is toxic if consumed and can lead to death. or Pterois spp. which is poisonous to touch and contact with skin can vary from very painful to deadly.

Introduction pathways;

The primary introduction pathway of alien species in the Mediterranean Sea is the Suez canal thus the majority of species entering the basin has a Indo-Pacific and Red sea origins. At the same time, many species have entered the Mediterranean Sea through shipping, by attaching on ships or through the ballast waters. Aquaculture and aquarium intentional or deliberate releases are also other pathways of introduction.


At the European level Regulation (EU) No 1143/2014 on the prevention and the management of the introduction and spread of invasive alien species, propose actions to all Member States for invasive alien species included in the list of species of the Union Concern. Find the list here.

Alien species are also included in Marine Strategy Framework Directive as a separate indicator for the assessment of the environmental status of the marine environment and its ecosystems by the Member States and in the Biodiversity strategy for 2020 as Target 5: combating invasive alien species.

Moreover, for species of the Tetraodontidae family, Regulation (EC) No 1021/2008 indicates that checks are to take place ensuring that no fishery products derived from these species will be placed on the market. While a number of other regulations also exists such as Regulation (EC) 708/2007  concerning the use of alien and locally absent species in aquaculture and Regulation (EC) 338/97 on the protection of species of wild fauna and flora by controlling their marketing.

Greece itself applies, ΝΟΜΟΣ 3937 ΦΕΚ 60/Α/31.3.2011 for the conservation of biodiversity and other provisions; according to which invasive alien species are subdivided into classes based on the risk of spreading and the estimated impacts on the structure and the functioning of the ecosystems. Depending on the risk category, the Ministry of Environment, Energy and Climate Change prepares management plans for the its invasive alien species. The plans include arrangements for the following topics:

(a) Prevention of the introduction of invasive alien species and information exchange

(b) Early detection and eradication, including the prevention of the spread of invasive alien species.

(c) Monitoring, control and long-term containment of invasive alien species.

(d) The restoration of the biodiversity of ecosystems affected by the settlement of alien invasive populations.

The team 

Project directors: Ioannis Giovos and Nikolaos Doumpas 
Data Collection: Nikolaos Doumpas, Georgios Romanidis-KyriakidisMary Maximiadi, Elena Mitsou, Ioannis Keramidas, Filippos Marakis

Identification Team:  

Fish: Francesco Tiralongo, Stefanos Kalogirou, Ioannis Giovos, Periklis Kleitou, Giacomo Bernardi, Ioannis Batjakas

Crustaceans: Theodoros Kampouris

Mollusca: Dimitris Poursanidis, Fabio Crocetta

Cnidaria: Fabio CrocettaJoachim LangeneckStefano PirainoFerdinando Boero

Echinoderma: Joachim Langeneck

Algae: Periklis Kleitou, Paolo Balistreri

Other Collaborators: Sara Almabruk, Lydia Alvanou, Rigers Bakiu, Michel Bariche, Murat Celik, Aris Christidis, Alan DeidunHalit Filiz, Panagiota Katikou, Stelios KatsanevakisSerpil Sağır OdabaşıSezginer TuncerMichail RagkousisUmut Uyan

Press release

Joint Press Release about the Toxic and Poisonous Alien Species occurring in the Mediterranean Sea

Publications in Press

Scientific Publications

a) in Peer-reviewed journals

b) in Conferences


The aim of the program is to establish long-term partnerships with all stakeholders like Marine Protected Areas Management Bodies, diving and fishing clubs, NGOs, Research Institutes etc., with the aim of informing the inventory of aquatic alien species in Greece. Therefore, iSea is collaborating with the Ellenic Network on Aquatic Invasive Species (ELNAIS) and the European Alien Species Information Network (EASIN). If you are willing to become a project partner, contact us at

International and National Bodies and Information Networks






MPA Management Bodies

Diving Centers




Collaborating Facebook Groups and Pages

Mediterranean Marine Life

Fauna marina mediterranea

Aliens in the Sea

Marine Biology Libya

Ξενικά ζώα σε Ελλάδα & Κύπρο

Ο Μυοκάστορας στην Ελλάδα


Στέκι ψαροτουφεκάδων

Spinning Anglers Team


Μέδουσες και Τσούχτρες στην Ελλάδα - Jellyfish in Greece

Heavy Casting Fishing



Informative Material

To receive the poster, contact us at


Useful links 

Ellenic Network on Aquatic Invasive Species (ELNAIS)

European Alien Species Information Network - EASIN



CIESM Atlas of Exotic Species in the Mediterranean

European code of conduct on recreational boating and invasive alien species