The effects of rainbow trout (Oncorhynchus mykiss) cage culture on water quality in the southern part of the Caspian Sea: Kiashahr and Abbasabad

Abstract

The environmental effects of rainbow trout cage culture were studied on different physicochemical parameters of water quality in two fish farms, Kiashahr and Abbasabad The concentrations of total phosphorus (TP), total Kjeldahl nitrogen (TKN), nitrate, total organic carbon (TOC), chlorophyll-a, oxygen saturation, and dissolved oxygen (DO) was measured beneath, eastward and westward of the cages. In phase II, a significant increase in the concentrations of TKN, nitrate, TOC, and chlorophyll-a beneath and 50 m east and west of the cages was detected compared to the control and the other stations (P0.05). In conclusion, rainbow trout cage farming in the southern Caspian Sea can cause a significant increase in water quality parameters up to a radius of 50 m of cages, which indicates an organic enrichment in the water surrounding the cages. Due to the growing trend of fish aquaculture in this region, proper management practices such as high-quality food and low feed conversion ratio are needed to reduce its negative effects on the marine environment.

Keywords

• caspian sea
• fish cage farming
• organic matter
• rainbow trout