Introduction and reintroduction

Introduction occurs in cases when a taxon is brought into a natural area, by human activity either intentionally or unintentionally, which is not within its natural distribution range or is an ecosystem in which it was not previously naturally found.
Reintroduction occurs in cases when a taxon is brought back into an area from which it previously disappeared and which still contains acceptable conditions for its survival or ecological conditions similar to those in place prior to its disappearance.
The introduction and reintroduction of taxa into nature is regulated under the Nature Protection Act (OG 70/05, 118/09) and the Ordinance on the manner of compiling and carrying out risk assessment studies on the introduction, reintroduction and breeding of wild taxa (OG 35/08). The introduction and reintroduction of new taxa into nature is prohibited in the Republic of Croatia, except with the permission of the Ministry and when the risk assessment study proves the introduction/ reintroduction of the taxon into nature to be scientifically founded.
The introduction of alien fish species into natural and semi-natural waters is strictly prohibited, as is the transfer of such species from fish breeding ponds into other aquatic habitats.
Should an alien species be unintentionally introduced in the area of the Republic of Croatia, or if there is justifiable suspicion that such an introduction will occur, the Minister may issue an order prescribing the steps to be taken to destroy the introduced alien species or to prevent its further spread and introduction.

TT

he Eastern mosquitofish is a freshwater fish species from the Poeciliidae family that was introduced to European rivers in the early 20th century from North America for the purpose of combating malaria, without any assessment of its possible impact on other fish species and other aquatic organisms. At that time, it was thought that the mosquitofish was the only fish species able to destroy the larvae of mosquitoes, the vector for malaria. However, it was later established that this species is very invasive and aggressive and has had a significant impact on the populations of other species, as it also feeds on fish eggs and fry, and insect and amphibian larvae.