Is it Alien to you…. Share it!!!

«Is it alien to you…Share it!!!» is a Citizen Science program, focused on the study of marine species in Greece, but also in neighbouring countries in the Eastern Mediterranean and especially Cyprus. The program depends on the observations / sightings from citizen scientists that love and /or spend a lot of time by the sea. As soon as an observation is submitted, the project’s team of researchers identifies the species and logs the sighting in the program’s database. Then, the information collected is utilized for scientific research, aimed at better managing and protecting the marine environment and the organisms that live within it.

How can you be a part of our program?

Every one of us can be a Citizen Scientist, as long as we are interested in broadening our knowledge and have the curiosity to discover more! There are two simple ways for you to participate in our program:

1. You can send directly to us your observations concerning the marine species that are already listed in the sections below. These entries should include a photograph or video and further information, such as the date and location of the sighting, depth, size, type of seabed and the way that the encounter took place (e.g. fishing, diving, snorkelling, etc.). You can either join our Facebook group and post about your observation or subscribe to our respective project on iNaturalistGR and add your entry on the platform.

2. You can inform your friends and generally anyone who might be interested to send us their observations!

Every week, one of the newly posted observations by Citizen Scientists is picked out as the #observation_of_the_week and it is shared on iSea’s social media, while also providing more info about the depicted species!

Progress so far & future steps…

The program has been implemented since 2016 and its primary purpose was researching the distribution and the spread of marine alien species. However, over time, it has evolved to encompass more aspects. Gradually, apart from postings about alien species, there was an increase in the number of observations concerning other species that people wished to be identified by the program’s research team, so as to be informed on the local marine biodiversity.

Every Citizen Scientist that participates in the program interacts with the aquatic environment in a different and unique way. Our community consists of fishermen, nature lovers, divers, and other groups of people that share a common ground; their willingness to learn more about our marine fauna and flora.
People’s urge and interest are what drives us to further foster their curiosity and desire for new knowledge and sea exploration, while at the same time giving everyone the opportunity to contribute to scientific research, aiming to the protection of the marine environment.

In this context, as a first step, we reshape «Is it alien to you…Share it!!!», and from now on, in addition to the observations of marine alien species, the following novel categories are added to the program’s list of species of interest: Protected Species, Exploited Species, Indicator Species, and Rare Species.
Thus, through the Citizen Science program «Is it alien to you…Share it!!!», by sending us your observations, you can actually contribute to the monitoring of the sea and help us fill the knowledge gaps, with the ultimate purpose of protecting it effectively.

Marine biodiversity through the eyes of the program

Alien Species

Alien Species are organisms found in environments other than their natural distribution area. Such species have the ability, not only to survive in diverse conditions and habitats but also to thrive and therefore, get established in new environments. The introduction of non-indigenous species into new habitats occurs either intentionally (e.g. through releases from aquariums) or accidentally (e.g. through ballast water from ships) and they have been attributed mainly to human-related activities. As soon as alien species are integrated into new habitats, their impact is usually negative, such as causing disturbances in indigenous species’ distribution and abundance, altering ecosystem services, and, last but not least, causing economic losses related largely to fishery and tourism.

The European Union requires its members to trace and report observations about alien species and their implications, in order for them to take appropriate measures for the implementation and conservation of suitable environmental conditions, according to the Marine Strategy Framework Directive. Moreover, the UNEP Mediterranean Action Plan urges to take action as far as the identification of alien species’ effects is concerned.

Differences among alien species provoke respectively different kinds of impact and, considering the significant lack of relative data, information about their presence and their spatial distribution is invaluable. Provide us with photographs of these species and contribute to the enrichment of scientific knowledge and their management.

You can find more information about it here.

The alien species that we gather material on:

Protected Species

Protected species are those that killing or endangering them is forbidden by law. This category includes information about species that are protected under:

  • The Greek Presidential Decree 67/81, pertaining to the protection of the endemic fauna and flora and the determination of a process that coordinates and controls their research.
  • The EU Habitats Directive (92/43/EU) is about the conservation of natural habitats, as well as of the fauna and flora, through their protection. Annex IV of the Directive lists species of great interest that require stringent protection.
  • The Bern Convention refers to the conservation of European wildlife and natural habitats. The Convention defines that all the parties are obligated to protect the populations of wild fauna and flora and their natural environment. All strictly protected species are classified in Annex II of the Convention.
  • The Barcelona Convention, concerning the Protection of the Mediterranean Sea Against Pollution. Annex II of the SPA/BD protocol of the aforementioned Convention is about areas that require special protection and about the biodiversity in the Mediterranean. It also includes endangered or threatened species.
  • The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) aims to ensure that international trade in specimens of wild animals and plants does not threaten the survival of the species. Annex II lists species that are not necessarily threatened by extinction, but their trading needs to be regulated so as to safeguard their survival.

Send us your observations of species in this category and help us better understand their current state! The protected species that we collect information about are the following:

Exploited Species

This category includes species of marine wild fauna, whose potential exploitation should be regulated for the purpose of ensuring their conservation. More specifically, the species in this category can be consumed, in such a way so as to ensure their survival.

In more detail, this category integrates species that are included in SPA/BD protocol’s Annex III of Barcelona Convention, concerning areas of special protection and biodiversity in the Mediterranean. It, also, lists species whose exploitation is regulated and are protected under Annex III of the Bern Convention.

You can provide observations concerning species you will find in this category and help in the comprehension of their distribution and abundance. The exploited species we are looking for are here:

Indicator species

A number of marine species have been selected as indicator species due to their sensitivity to changes in their natural habitat. Such changes include environmental alterations and/or anthropogenic disturbances, thus monitoring these species allows researchers to track changes in the marine environment. For instance, nudibranchs are species that are very useful for understanding the impact of global warming, due to their short lifespan and faster response to changes in the environment. Therefore, monitoring their ranges could provide useful insights into the impact of climate change. The species we are interested in collecting data are: Acanthurus spp., Cotylorhiza tuberculata (Mediterranean jellyfish), Felimare picta, Flabellina affinis (purple sea slug), Mnemiopsis leidyi (sea walnut), Pelagia noctiluca (mauve stinger/ purple-striped jelly), Peltodoris atromaculata (dotted sea slug/ sea cow), Sciaena umbra, Sparisoma cretense (Mediterranean parrotfish).

Send us your observations of species in this category and help us better understand the changes that are happening to the marine environment!

Rare species

Rare species are organisms that are scarce or uncommon in a specific area. However, it is important to note that some species may fall in this category in one area, while in not another, due to their population and expansion. Such species, although they are considered rare, they are not necessarily threatened. Rare species are considered important not only for their unique characteristics and significant ecological functions but also because they often have a major impact on the ecosystem. If any changes occur in their distribution, their conservation status may subsequently impact the ecosystem functions that they provide. For example, species that are considered rare in our region and we are interested in collecting information include: Lophotus lacepede, Physalia physalis and Ranzania laevis.

Unfortunately, rare species may suffer much more from overexploitation and disturbances compared to well-established and indigenous ones. Observations of these species are of vital importance for filling knowledge gaps and developing tailored management measures!

The program’s team

Project Manager: Vasilis Minasidis

Data collection & Program Implementation: Alexandros Kaminas, Athina Ziou, Alexandra Doulgeri, Stavros Kampourelis, Emmanouil Symigdalas, Dimitris Pafras

Fish Identification: Francesco Tiralongo, Stefanos Kalogirou, Nikos Doumpas, Ioannis Giovos, Periklis Kleitou, Giacomo Bernardi

Crustaceans Identification: Joachim Langeneck, Periklis Kleitou, Fabio Crocetta, Niki Chartosia

Mollusca Identification: Fabio Crocetta, Dimitris Poursanidis

Cnidaria Identification: Fabio Crocetta, Joachim Langeneck, Stefano Piraino, Ferdinando Boero

Echinoderma Identification: Joachim Langeneck

Algae Identification: Periklis Kleitou, Kostas Tsiamis

Sessile invertebrates Identification: Vasilis Gerovasileiou

Other partners: Sara Almabruk, Lydia Alvanou, Rigers Bakiu, Michel Bariche, Murat Celik, Aris Christidis, Alan Deidun, Halit Filiz, Panagiota Katikou, Stelios Katsanevakis, Serpil Sağır Odabaşı, Sezginer Tuncer, Michail Ragkousis, Umut 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

  • Marmara, D., Keramidas, I., Paravas, V., Giovos, I. (2017). The invasive Lionfish in Greece. Workshop on the Lionfish in the Eastern Mediterranean Sea: New problems, new solutions: Distribution, Eradication & Utilization, Antalya, Turkey.
  • Giovos, I., Doumpas, N., Ioannou, I., Sarafidou, G., Marmara, D., Paravas, V., (2017). Is Alien to you…Share it!!! A Citizen Science Project on alien species in Greece. ESENIAS Conference, Sofia, Bulgaria.
  • Keramidas, I., Doumpas, N., Kleitou, P., Tiralongo, F., Bernardi G., Romanidis-Kyriakidis, G., Marmara, D.,  Giovos, I. (2018). Is it Alien to you?? Share it!!: Citizen scientists monitoring Non-Indigenous species in Greece. 12th Panhellenic Symposium of Oceanography & Fisheries Ionian University, Corfu, 30 May – 3 June 2018
  • Doumpas, N., Giovos, I., Kalogirou, S. (2018). The misconception of pufferfish consumption in Greece through social media sentiment analysis. ESENIAS & DIAS Conference 2018, 8th ESENIAS Workshop, Bucharest, 2018
  • Giovos, I., Doumpas, N. (2019). Alien species: iSea actions in recording marine alien species and raising public awareness on edible alien species. First regional meeting in the context of the project Invalis, Athens, 29 October 2019
  • Doumpas, N. (2020). Pick The Alien, Introducing edible alien species to the Greek market. Lionfish Knowledge Exchange Workshop, Adressing Invasive Alien Species Threats at Key Marine Biodiversity Areas Project, MarIAS, 4 November – 5 November 2020
  • Doumpas, N. (2020). Pick The Alien. Developing the lionfish seafood market in Greece. Virtual DEMA 2020, Lionfish Update Panel: Lionfish Universe, 20 November 2020


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 MER – Marine & Environmental Reserach Lab in Cyprus, 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 [email protected]

Project partners

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


In 2019 the project funded by Vodafone Foundation in the context of the WoD project. Find the report here .

Informative Material