A total of 22 fish species have been introduced into the inland waters of Serbia, either intentionally or accidentally. This paper provides a summary of data concerning time and reason of introduction, mode of expansion, degree of acclimatization, impact on native fish and estimated area of recent distribution. Four of the non-native fish species currently occupy more than 51% of Serbian territory while 5 of them occupy between 21-50% of territory. This paper reviews impacts of introduced freshwater fish in Serbia based on collected data.

The content of 11 heavy metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Zn) was analysed in certain tissues and organs in 12 fish species in the river Danube, Vojvodina (Yugoslavia). The studied selectivity of accumulation of heavy metals varies in these fish species. Most of the heavy metals were deposited in higher concentrations in the intestines than in the muscles. However, this ratio was just the opposite in piscivores.

Concentrations of eight heavy metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were determined in water and in the muscles and organs (gills, liver, spleen, gonads) of fi sh: planktivores (Alhumus alhumus), benthivores (Carassius auralus. Cyprinus carpio, Ti nea linca) and piscivores (Anguilla anguilla. Esox lucius. Microplerus salmoides. Silurus glanis. Slizosledion lucioperca) inhabiting the Yugoslav section of the Danube (main ri ver and canal system Danube-Tisa-Danube). Fish were caught by electrofishing in 1991. The heavy metal (HM) content of fish muscles and organs was higher than in the water. Planktivorous species accumulated the lowest amounts of HM whereas benthivorous fish concentrated the largest amounts; piscivorous fish from the Danube had a lower HM content than those inhabiting the canal system, where the HM content of the water was higher. In order to estimate pollution of a portion of the Danube Basin in Yugoslavia, water quality classes based on the content of individual HM in ri ver water, and in the ichthyofauna, were determined.

Fish farming is the only type of aquaculture in Serbia. Fish farming is mostly carried out in cyprinid and salmonid (trout) fishponds (over 95% of the total fish produced), with considerably lower ichthyoproduction being practiced in cages and some bodies of open water such as reservoirs and channels. Serbian aquaculture currently includes 12 fish species, 4 of which are allochthonous (non-native). With the exception of the rainbow trout (Oncorhynchus mykiss) and, to a certain extent, grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis), allochthonous fish species have no economic importance. The presence and abundance of certain allochthonous species in fishponds and open waters have a negative effect on the total ichthyoproduction.Keywords: Serbia, allochthonous (non-native) fish species, aquaculture RezimeGajenje riba jedini je oblik akvakulture u Srbiji. Skoro u potpunosti realizuje se u šaranskim i salmonidnim (pastrmskim) ribnjacima (više od 95% ukupne riblje produkcije), dok se značajno manja ihtioprodukcija ostvaruje u kavezima i nekim otvorenim vodama (akumulacijama i kanalima). Akvakultura Srbije trenutno uključuje 12 ribljih vrsta, od kojih su 4 alohtone (introdukovane). Izuzev kalifornijske pastrmke (Oncorhynchus mykiss) i, u određenom stepenu, belog amura (Ctenopharyngodon idella), belog tolstolobika (Hypophthalmichthys molitrix) i sivog tolstolobika (Hypophthalmichthys nobilis), druge alohtone vrste nemaju ekonomskog značaja. Prisustvo i masovnost pojedinih alohtonih vrsta u ribnjacima i otvorenim vodama ima negativan uticaj na ukupnu ihtioprodukciju.Ključne reči: Srbija, alohtone (introdukovane) riblje vrste, akvakultura Detaljan rezimeNa teritoriji Republike Srbije (površine 88361 km 2 ) postoje povoljni hidroekološki uslovi za ihtioprodukciju. U ihtiofauni Srbije prisutno je 95 vrsta iz 27 porodica, od kojih su 23 vrste iz 11 porodica alohtone (introdukovane iz drugih područja). Različiti su razlozi za introdukciju -gajenje u akvakulturi, borba protiv planktonske i makrofitske eutrofikacije, poribljavanje u svrhu sportskog ribolova i drugi. Generalno, introdukcije većine ribljih vrsta imaju negativan efekat na autohtonu ihtiofaunu. Gajenje riba predstavlja jedini oblik akvakulture u Srbiji, sa zanemarljivim gajenjem drugih akvatičnih organizama (rakova i žaba). Ostvaruje se u šaranskim i salmonidnim (pastrmskim) ribnjacima (ukupne površine oko 14000 ha sa procenjenom godišnjom ihtioprodukcijom od 15000 t) i značajno nižom produkcijom riba u kavezima i otvorenim vodama (akumulacijama i kanalima). U akvakulturi Srbije trenutno egzistira 12 vrsta riba, od kojih su 4 alohtone. Kalifornijska pastrmka (Oncorhynchus mykiss) je alohtona vrsta koja ima najveći komercijalni značaj. Broj pastrmskih ribnjaka procenjen je na 130 (ukupne površine 13-14 ha) sa godišnjom produkcijom od 1500-2000 t. Uprkos velikim količinama vode I klase kvaliteta, ostvaruju se niski prinosi (10-15 kgm -3 ), prvenstveno uslovljeni činjenicom da nek...

The studies on the ichthyofauna of Serbia that have been conducted so far indicate the sporadic tench (Tinca tinca L.) presence in typical habitats. The hydroenvironmental conditions necessary for the survival of this fish species are highly variable and, generally, are more favourable in the northern part of the country (the Vojvodina Province). Although the tench presence has been registered at over 30 sites, there is a tendency of a decrease in population abundance. This is due to the reduction of the surface area of the macrophyte-covered flood zones induced by the damming and regulation of rivers, high water level fluctuations, and water amount reduction in the majority of watercourses, a massive increase in the number of allochthonous phytofagous species, reservoir sediment deposition, water quality deterioration and other factors. The tench conservation status in Serbia is officially designated as Low Risk - Least Concern. It may be transferred to a higher category if the tendency towards deterioration of survival conditions for the species should continue