Nutrient inputs, trophic status and water management challenges in the transboundary Lake Skadar/Shkodra, western Balkans

A transboundary water quality-monitoring program was conducted in 2007-2009 to investigate the trophic status and nutrient budget of Lake Skadar/Shkodra, which is a large, shallow lake shared by Albania and Montenegro. The parameters included, amongst others, total phosphorus (TP), total nitrogen (TN), suspended particulate matter, chlorophyll a, phytoplankton, transparency, temperature and oxygen levels. In addition, hydrological data were scrutinized. The results show that inputs from the tributaries amounted to 176 tons of TP and 3 200 tons of TN, with annual area specific loads of 50-70 kg/km2 of TP and 950-1100 kg/km2 of TN. Despite relatively high inputs, data from the lake indicate that it is presently in a mesotrophic condition, probably due to its large volume and low water residence time. It is assumed that water bodies in the Western Balkans are under increased environmental pressure due to the economic and societal development in the region. In our study, interactions with stakeholders revealed that this also applies to Lake Skadar/Shkodra, but at the same time, the stakeholders suggested a number of mitigation options that can improve the situation. In addition, harmonized transboundary monitoring and increased data transparency were deemed important to improve future decision-making