Non Native Species  


In recent years, the problem of non-native species has been increasingly observed, with the majority being brought to the new environment mostly by human (intentional or unintentional) treatment. According to recent data, there are a growing number of non-native species in aquatic ecosystems that pose a threat to native species. The same non-native species do not, in principle, present the problems they exhibit when the species becomes invasive. To understand that a species is so successful in its new environment that, through its expansion and activities, it threatens native species, affects biodiversity, ecosystem services, human health, and can cause great economic damage.


Red dots represent non native invasive species finds made by FRIS.

The following are basic definitions summarised under the Convention on Biological Diversity and EU Regulation No. 1143/2014:

o Indigenous species are species, subspecies or taxa of a lower category that are within their normal natural range, even if only occasionally. The species has reached such areas on its own, with natural spread.

o Non-indigenous species are species, subspecies or taxa of a lower category introduced into an area other than their natural range or area. which could themselves be achieved through natural expansion. This also applies to any part of the organism capable of survival and reproduction (germ cells, eggs, larvae).

o Transitional non-native species (acclimatised species) are species that only occur occasionally in an area and do not form permanent populations. They are only maintained by resettlement.

o Potentially invasive species are species, subspecies or taxa of a lower category that are already invasive in an area with similar climatic conditions to ours, or their related species that have already proven invasive in an area.

o Invasive non-native species (hereinafter referred to as INNS) are only those species, subspecies or taxa of the lower category that, through their dissemination, endanger or adversely affect biodiversity and ecosystem services.

o A naturalised species is a species that, in the new environment, without human assistance, reproduces independently and regularly, maintains populations, but does not yet cause any detectable damage to the environment.

o "Door knocker" species are called non-native species that are not present in Slovenia, but they are more likely to enter our country due to their presence and distribution in neighbouring countries. As these species have a high potential to enter Slovenia, special attention should be paid to them and every effort should be made to prevent their introduction and spread.

o Potentially non-native species are those species that may have already spread to Slovenia naturally from neighbouring countries, as well as those that have already been found or cultivated in Slovenia but have not been able to establish a naturalised population.

EU Regulation no. 1143/2014

In 2014, the EU adopted a new EU Regulation no. 1143/2014 of the European Parliament and of the Council on the prevention and control of the introduction and spread of invasive alien species.

EU Regulation entered into force on 1 January 2015 and is binding on all Member States. The regulation sets out "rules to prevent, as far as possible, to minimise and mitigate the harmful effects of the deliberate and unintended introduction and spread of invasive alien species on biodiversity in the Union."

Pursuant to this Regulation, on 13 July 2016, the European Commission adopted Commission Implementing Regulation 2016/1141 adopting a list of invasive alien species of concern to the Union. This Regulation is accompanied by an initial list of invasive alien species of concern to the Union, on which 37 INNS have been classified. The Commission shall thoroughly review this list every 6 years and, if necessary, update it in the interim. The list was updated by two more regulations, on 12 July 2017 with Commission Implementing Regulation (EU) 2017/1263 adding 12 more species and on 25 July 2019 with Commission Implementing Regulation (EU) 2019/1262, to which 17 more species were added. Thus, a total of 66 INNS are now listed, of which 30 are animal and 36 are plant. All species on the Union list are subject to the most stringent anti-proliferation measures.

It is forbidden to import into the Union, reproduce, cultivate, transport, buy, sell, use, exchange, possess or release them into the environment!

IMPACT ON BIODIVERSITY: INNS can pose a major threat to native species and habitats through competition, predation and disease transmission.

IMPACT ON ECOSYSTEM SERVICES: INNS can disrupt the ecosystem balance, affect its properties and service delivery itself, thus affecting the entire ecosystem function.

IMPACT ON HUMAN HEALTH: INNS can be potential carriers of certain diseases, can cause allergies and various skin injuries.

The Union list currently lists 10 invasive alien species whose habitat is exclusively water:


Pseudorasbora parva - Stone moroko, topmouth gudgeon 

Lepomis gibbosus - Pumpkinseed

Perccottus glenii - Chinese sleeper

Plotosus lineatus - Striped eel catfish


Procambarus clarkii - Red swamp crayfish

Procambarus fallax f. virginalis - Marble crayfish

Faxonius limosus - Spinny cheek crayfish

Pacifastacus leniusculus - Signal crayfish

Faxonius virilis - Virile crayfish

Eriocheir sinensis - Chinese mitten crab

quick Contact

Fisheries Research Institute of Slovenia
+386 1 24 43 400
+386 1 24 43 405