Evaluation of water quality variables and their effects on fish life in Asarsuyu Stream (Düzce/Turkey)

Abstract

Asarsuyu Stream is one of the tributaries of Melen River located in the Western Black Sea Region in Turkey. It is influenced by intensive industrial activities, agricultural and urban areas. Ichthyofauna of the stream consists of Squalius pursakensis, Barbus escherichii, Alburnoides tzanevi, Rhodeus amarus, Alburnus derjugini, Gobio baliki, Cobitis splendens, Oxynoemacheilus banarescui, Gambusia holbrooki. In order to assess the impacts of the water quality on fish health, the water quality of Asarsuyu Stream was determined by some physiochemical (temperature, conductivity, salinity, total dissolved solids, pH, dissolved oxygen) and chemical (nitrite, nitrate, ammonium, phospahate, sulphate, calcium, magnesium, chloride, sodium and potassium) parameters were monitored seasonally during February and November 2018. All of the data obtained experimentally were compared according to the criteria of SKKY (Water Pollution Control Regulation in Turkey) and evaluated according to the criteria European Commission. The obtained data indicated that oxygen may be a critical factor for fish survival especially during spring and autumn in the study area. According to our results, the monitoring stations have class I-IV water quality in terms of nitrigenous compounds. Especially nitrite and ammonia, have been determined to reach critical levels for fish health.