Estimate environmentally friendly fish farming in four lakes in Telemark

Abstract

Fish farms in Norway are expanding following the growing demand for arctic fish. This is also raising concern about environmental issues. This study conducted a water survey in 4 lakes in Telemark, including Tinnsjø, Seljord, Fyresvatn and Nisser. The aims are to find out background information about water quality and estimate environmentally friendly fish farming based on total phosphorus and concentration of chlorophyll_a. Fieldtrips in summer 2017 and 2016 demonstrated oligotrophic status of those large and deep lakes. Most of water parameters met good to very good quality according to limits set up by Norwegian Institute for Water Research (NIVA) excepted total nitrogen in Seljord and total phosphorus in Nisser and Fyresvatn in 2017. Potential production of farmed arctic char was estimated by using linear function and exponential function developed by Espen Lydersen (2015) and previous studies. Tinnsjå had highest potential which can produce approximately 1900 tons/year, Fyresvatn could produce approximately 800 tons while that value was not worth considering in Seljord and varied in Nisser. Uncertainty might occur throughout the whole study due to both systemic and random errors and calculation and natural events. This study had supplied useful data for those who are interested in water chemistry as well as farmed fish producers.