engleski

HISTORY OF THE ALIEN INVASIVE FRESHATER CRAYFISH IN CROATIA

Until recently Croatian freshwater ecosystems harboured only indigenous European crayfish species (ICS). The first appearance of the non- indigenous crayfish species (NICS), the invasive spiny-cheek crayfish Orconectes limosus, was recorded in Kopački rit in 2003 where it has spread naturally through the Danube River from Hungary. In 2008, another invasive species, the signal crayfish Pacifastacus leniusculus, was recorded in the Mura River, because of natural spread from Slovenia. Since that time, we are witnessing continuous NICS spread via natural or human- mediated ways throughout Croatian freshwaters. Due to their biological and ecological characteristics, they have severe adverse impacts on ICS. Moreover, they are latent carriers of the pathogen Aphanomyces astaci, causative agent of the disease crayfish plague that is lethal for ICS. The aim of this presentation is to give an overview on the NICS invasion in Croatia and their impact on ICS. Today, NICS comprise 43% of the total number of crayfish species present in Croatia. Since 2003, NICS have occupied 30 out of 327 10x10km grid cells of Continental Croatia. At least in two localities, they have displaced ICS in a short period of time (1-3 years), and their dispersal speed ranges between 24 km/year (downstream) and 2.5 km/year (upstream). In contact areas between ICS and NICS, transmission of A. astaci was recorded.

signal crayfish ; marbled crayfish ; spiny-cheek crayfish ; astacofauna

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