engleski

REMOVAL OF INVASIVE FISH SPECIES FROM THE PLITVICE LAKES WATER SYSTEM HELPS INCRESING VIABILITY OF NATIVE FISH SPECIES AND RESTORING NATURAL HABITAT CONDITIONS

Native fish community of the Plitvice Lakes is not rich in species, but comprises some interesting elements and important genetic diversity. It contains only four species: the Danube trout (Salmo labrax), minnow (Phoxinus sp.), Italian spined loach (Cobitis bilineata) and Italian golden loach (Sabanejewia larvata). Previous investigations proved that the Danube trout in the Plitvice Lakes National Park is still presented with ‘pure’ populations, which have become rarity throughout most of Europe. Moreover, ancient haplotypes are very important for the viability of the whole species. At the same time, several threats to survival of the Danube trout have been noticed, invasive species being one of the most problematic. The fish community of the Plitvice Lakes water system have been severely altered in the 20th Century and today the alien species dominate in the lakes and are also present in rivers and streams of this water system. The negative effects of those alien species on the native fish community could be observed on several levels: predation on larval and adult stages of individuals of native species, competition for resources, and significant alteration of habitat conditions. In order to reduce negative effects of the alien species and help restoring populations of the native fish species, we have designed and implemented a programme for removal of invasive fish from the Prošćansko Lake, as well as from the rivers and streams where the Rainbow trout (Oncorhynchus mykiss) have been recorded. Intensive removal has been conducted from May to October 2021., with different methods employed in various habitats. More than 700 kg of nonnative fish were removed. Results of this project, as well as plans for future activities in the Plitvice Lakes are discussed.

Competition ; Predation ; Habitat alteration ; Non-native fish species removal ; Prošćansko Lake

Sažetak proizlazi iz Projekta uklanjanja invazivnih vrsta riba u Nacionalnom parku Plitvička jezera