ANNALES • Ser. hist. nat. • 11 • 2001 • Suplement - Abstracts
Interdisciplinary Workshop "Pattern and Process in Balkan Biodiversity", Koper, September 25-28 2001
THE PATTERN OF DISTRIBUTION OF THE FRESHWATER FAUNA 
OF THE BALKAN PENINSULA
Petru M BANARESCU 
Institute of Biology, Bucharest, Romania
Each river drainage in the Balkan Peninsula has its own faunistic pecularities. The Danube Basin's aquatic fauna 
has a marked central European character. Two of the ten endemic fishes of the basin are confined to its southern and 
south-western (i.e. its Balkanic) sector. Many genera of higher crustaceans and hydrobioid snails, especially hypo- 
gean taxa, are endemic to the south-western area of the Danube Basin, some of them are related to western Balkanic 
genera, however, the area also features a lot of endemic species belonging to western or Holo-balkanic genera.
Central European and Danubian fish and aquatic invertebrates are also present in the rivers of the northern Ae­
gean watershed; there are differences between the eastern Aegean rivers (R. Maritza, R. Mesta, R. Struma) and the 
western ones (R. Vardar and others). In the eastern Aegean rivers are present widely distributed European species in­
habiting standing or slowly running water, while in the western rivers live rheophilic species, shared only with the 
Danube or with a few other neighbouring rivers; none of them live either in the eastern Aegean drainages or in the 
western Balkanic ones.
The aquatic fauna of the western Balkan is the richest in Europe and includes a very high number of endemic 
genera and species. Most species have restricted distributions in the western Balkan area; the four Dalmatian riverine 
drainages and especially the lakes of Skadar and Ohrid each have their own endemics. The southern Balkans in­
cludes numerous endemics too, most having quite restricted ranges. Several genera and species are restricted to two 
or three of the five Balkan districts. These taxa can be designated as "Balkanic" in wide sense.
The efficiency of water divides as barriers differs amongst various groups. These provide very efficient barriers for 
fishes, crayfishes and large sized molluscs, and so explains the great differences between the fish faunas of the west­
ern Balkan and the Danube drainages. Water divides are, on the contrary, less efficient barriers for hypogean aquatic 
animals such as hydrobioid snails and aquatic insects - the genera and species of these groups, present in the south­
western tributaries of the Danube, have marked west Balkanic ties.
The following historical biogeographical categories can be identified:
- those with central European or Palearctic ties: species more widely distributed and with different ages in the 
Peninsula. The central European species present in the Aegean rivers dispersed through the Black Sea when it 
was a brackish water body, whilst the Danubian rheophilic species dispersed by mean of river captures from the 
Danube's tributaries in the R. Vardar.
- those with Anatolian or western Asian affinities, e.g. the fish genus Pseudophoxinus, the subgenera Luciobarbus 
of Barbus and Bicanestrinia of Cobitis, and a speciose lineage of hydrobioid snails (raised by Radoman to family 
rank "Orientallinidae").
- members of lineages of marine Tethyan origin: species of the epigean snail genera Theodoxus and Melanopsis 
and a numerous hypogean species of atyd and peracarid crustaceans.
- offshoots of the Mediterranean marine fauna.
Key words: biogeography, Balkan, hydrology, river catchments, faunal provinces
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