WATER QUALITY AND STRUCTURE OF FISH POPULATIONS IN DIFFERENT AREAS OF THE TIMIS RIVER

Researchers have been conducted on the Timis River, during which 6 fishing stations were established where 6 determinations of the chemical composition of water were made and the existing fish populations were evaluated. In the water of Timis River, from springs to the mouth, increased the 5 days-biochemical oxygen demand (BOD5 from 1.80 to 3.58 mg O-2/l), also the accumulation of nitrates (from 1.82 to 2.77 mg/l), nitrites accumulation (from 0.015 to 0.045 mg/l), chlorides (from 2.50 to 8.51 mg/l) and hardness (from 1.27 to 5.52 dH degrees). In the Timis river 36 fish species have been identified, which proves a good ecological status. Depending on the physic-chemical properties of the water, salmonids fish population was spread only in the mountain area, and cyprinids in hills and low land area. A large distribution was expressed in Barbel, Chub, Chased the Umber and Spirlin, which were found between the Teregova fishing station (mountain area), Lugoj stations (hilly area) and stations from Sag and Graniceri (lowlands area). In the warm waters of low lands were found: Bream, ide, pike-perk, sterlet, Verner, eels and Wheatear.