Knowledge of the status of the freshwater fish fauna of Croatia is limited. A paper on the status of freshwater fish in Croatian Adriatic river systems was published in 1995 (Mrakovcic et al., 1995).
There are two large river systems within Croatia, the Danube and Adriatic systems. These are divided by the Dinarid Alps , extending as far as Prkletje Mountain. The Adriatic catchment can be divided into three regions: 1. the Istrian Peninsula; 2. the Croatian maritime region; and 3. the karstic region (Krska polja) with valleys and underground streams in the inland Adriatic basin. The Istrian Peninsula has two main large rivers, the Rasa and Mirna. Rivers in this region are quite polluted. Rivers of the Croatian maritime region include the Rijecina which is extremely polluted in its lower reaches. The Zrmanja River is the only large river in this area, with a length of 69 km. There is already one hydroelectric plant on this river and more are planned. The Krka River, running through limestone areas, is a site of great natural beauty and importance. The Cetina River is characterised by its abundance of water and underground connection with the Bosnian karstic region. It has five hydroelectric plants along its length and two more are planned. The Krska polja area is a special region that is connected by an underground hydrographic network of rivers. Flood waters in valleys in this area have been controlled, completely changing the hydrological conditions. Intensive agriculture involving the use of fertilisers and pesticides has also worsened the water quality of this region. Near Ravni Kotari is Lake Vrana, an oligotrophic 3000 ha reservoir, artificially connected to the sea. It is inhabited mainly by species introduced from the Danube basin.
Major threats to species within Croatia come from pollution, river regulation and the construction of hydroelectric and water supply reservoirs. In the Adriatic area there are 12 new hydroelectric plants and 12 are planned. Cold water and cave fish are those most likely to suffer from such activities.
The fish fauna of all Croatian Mediterranean rivers has been poorly researched. It is important to list all important habitats and species. One of the large rivers, the Krka, should be left in its natural condition. Small streams and wells in the karstic region and their fish fauna should be recorded. It is possible that some endemic species remain to be recorded in this area. At present there is no list of endangered species in Croatia. Amongst the most endangered species of the Adriatic catchment are all species of the genera Paraphoxinus and Salmothymus, plus the species Leuciscus polylepis and Aulopyge hugeli.
Contact: Milorad Mrakovcic, Fisheries Centre, Kneza Mislava 2/V, 41000 Zagreb, CROATIA; Stjepan Misetic, Elekroprojekt, Vukovarska avenija 37, 41000 Zagreb, CROATIA; Meta Povz, Institute for Fisheries, Zupanciceva 9, 61000 Ljubljana, SLOVENIA.
|Geography and Climate
Croatia is located in Southeastern Europe, bordering the Adriatic Sea, between Bosnia and Herzegovina and Slovenia. Border countries are Bosnia and Herzegovina 932 km, Hungary 329 km, Serbia and Montenegro 266 km (241 km with Serbia; 25 km with Montenego), Slovenia 670 km.
Climate is of Mediterranean and continental; continental climate predominant with hot summers and cold winters; mild winters, dry summers along coast. Terrain consists of geographically diverse; flat plains along Hungarian border, low mountains and highlands near Adriatic coast, coastline, and islands. Elevation extreme has the lowest point in Adriatic Sea 0 m and highest point in Dinara 1,830 m. Natural resources are oil, some coal, bauxite, low-grade iron ore, calcium, natural asphalt, silica, mica, clays, salt. Land use: arable land: 21%, permanent crops: 2%, permanent pastures: 20%, forests and woodland: 38%, other: 19% (1993 est.). Irrigated land: 30 sq km (1993 est.). Natural hazards are frequent and destructive earthquakes
Environmentâ€”current issues: air pollution (from metallurgical plants) and resulting acid rain is damaging the forests; coastal pollution from industrial and domestic waste; widespread casualties and destruction of infrastructure in border areas affected by civil strife .
Geographyâ€”note: controls most land routes from Western Europe to Aegean Sea and Turkish Straits
Ref. Anonymous, 1999