The first round of workshops on invasive alien species completed

July 31, 2020 – today ended the first round of workshops on three invasive alien species that Oikon, together with partner Hyla Association and associates Nikola Tvrtković, PhD and Matej Faller, PhD executed as part the project of the Ministry of Economy and Sustainable Development “Development of a management and control system for invasive alien species”, co-financed by the EU Cohesion Fund.

At a total of 18 workshops held throughout Croatia, from Osijek to Dubrovnik, relevant stakeholders gained insight and shared their views and experiences with the small Indian mongoose (Herpestes javenicus auropunctatus), signal crayfish (Pacifastacus leniusculus) and red-eared slider turtle (Trachemys scripta), which will be used in the development of a management plan for these invasive alien species.

This round will be followed by two more rounds of workshops – in autumn and winter – where concrete measures to control populations and prevent the spread of these invasive alien species will be discussed with stakeholders.

The main purpose of the project is to contribute to the development of the prevention and management system of invasive alien species in Croatia, through the development of action and management plans, as well as manuals on the identification and treatment of invasive alien species. The documents should improve the control and mitigate the harmful impact of invasive species on native species and habitats.

About invasive alien species

Due to the increase in global trade, transport, tourism and climate change, the number of invasive alien species in the EU is constantly increasing and in 2014 the Regulation of the European Parliament and the Council on the prevention and management of the introduction and spread of invasive alien species was adopted.

It is estimated that around 12,000 alien species have been introduced in Europe, of which 10-15 % are invasive. In accordance with that, the European Commission, through the implemented acts, adopted the so-called “Union list”, or a list of species that are considered to be of concern in the EU. The list also includes these three invasive alien species:

The small Indian mongoose (Herpestes javenicus auropunctatus), is a widespread species in the Republic of Croatia. Due to the ecology of the species, this species has damaged the indigenous fauna in many areas and is considered responsible for the reduction of some bird species populations and reptiles, and the spread of disease.


Signal crayfish (Pacifastacus leniusculus) originates from North America and in the last ten years has spread through Croatian watercourses, along the Mura, Drava and Korana rivers. Establishing its dense populations, it significantly negatively affects the populations of native freshwater crab species by competing for food and habitat, with the greatest danger being the transmission of highly infectious disease crayfish plague. In addition, an irreversible change in the river food web structure has a negative impact on other species, especially fish, and over time on fishing.


The natural distribution of the red-eared slider (Trachemys scripta) is in the left bank of the Mississippi River in the USA  and its spread to Croatia and the rest of the world began in the 1970s when it was sold as a pet and was then intentionally or accidentally released into nature where it became invasive. The red-eared slider turtle has an ecological impact on several species of plants and animals and is the biggest threat to our native, endangered European pond turtle (Emys orbicularis) with which it competes for food and habitat and successfully suppresses it. The species can also be a carrier of animal diseases and parasites, and even a carrier of salmonella for humans.


For the reasons mentioned above, the European Commission demands the development of management plans that would effectively control populations of these three invasive alien species.

The workshops were held in accordance with the valid instructions and measures for protection against COVID-19 disease.

Oikon d.o.o.

Oikon d.o.o.