SHORT COMMUNICATION Evaluation of DNA damage in haemolymph of freshwater mussels Unio pictorum from Lake Skadar Svetlana Perovic 1 & Bojana Sljukic 1 & Maja Šrut 2 & Andrej Perovic 1 & Göran I. V. Klobučar 2 Received: 7 October 2018 /Accepted: 10 July 2019 # Institute of Zoology, Slovak Academy of Sciences 2019 Abstract This study was carried out on mussels Unio pictorum as test organism, in order to identify the possible pollution in Moraca River and Lake Skadar. Lake Skadar, located in a karst area in the outer part of the south-eastern Dinaric Alps, is the largest of the Balkan lakes and has a surface area which fluctuates seasonally from approximately 370 to 600 km 2 . The mussels U. pictorum were exposed in cages by 30 individuals on several locations for the period of three weeks. Following the three-week exposure, haemolymph samples were taken from mussels and tested using the Comet assay and micronucleus test. DNA damage on living organisms, made by pressure of pollutans and other stresors were evaluated. In brief, the results of investigation show that DNA damage is certainly present in caged U. pictorum mussels, and that it is caused by pollution in the Moraca River, which affects ecological and toxicological status of Lake Skadar. Keywords Unio pictorum . Lake Skadar . Comet assay . Micronucleus test Introduction Due to the complexity of hydrological structure of aquatic ecosystems and numerous potential pollution sources, identi- fication and assessment of the pollution levels is often difficult (Lafont 2001). Organisms in aquatic environments are gener- ally exposed to a complex mixture of chemicals, including the parent compounds and their transformation products, causing multiple damages to organisms (Bolognesi and Cirillo 2014). For this reason, biomarker studies, used in the evaluation of environmental health as an indicator of toxic effects of envi- ronmental pollutants are developed (Çok et al. 2011). Over the last few years, use of molecular biomarkers has enabled early detection of changes in the ecosystem. This is important, since numerous disturbances at the molecular level are followed by disturbances at the higher organisational levels: populations and biocenoses, so early diagnosis and determination of the stressor and/or pollutant impact in living organisms enables timely undertaking of appropriate safeguard measures. One of the most important molecular biomarkers is single-cell gel electrophoresis (SCGE), or comet assay, used to measure the number of DNA strand breaks. Due to its versatility and adapt- ability, the comet assay has been successfully used to detect genotoxic activity in different environmental compartments and test organisms (Kosmehl et al. 2004). Among aquatic organisms suitable for biological monitoring, mussels occupy a prominent place due to their wide geographic distribution, their abundance and accessibility in the field as well as in aquaculture (de Lapuente et al. 2015). Since they filtrate large quantities of water, they may also ingest a large quantity of pollutants into their bodies. Usually, pollutants enter the met- abolic paths of the organism, followed by degradation or de- positing in the tissues. A number of pollutants affect enzyme activities or the genetic material, while a number of them are accumulated into the tissues of bivalve molluscs, having a chronic effect. For that reason, bivalve molluscs are good bioindicators for the aquatic ecosystem quality monitor- ing (Klobučar et al. 2008; Štambuk et al. 2008, 2009; Kolarević et al. 2015). Situated along the Montenegro-Albanian border, Lake Skadar is the largest lake of the Balkan Peninsula with unique characteristics, wide range of endemic and rare or endangered * Svetlana Perovic svetlanaperov@gmail.com 1 Faculty of Science and Mathematics, Department of Biology, University of Montenegro, Dzordza Vasingtona bb, Podgorica, Montenegro 2 Faculty of Science, University of Zagreb, Department of Biology, Rooseveltov trg 6, Zagreb, Croatia Biologia https://doi.org/10.2478/s11756-019-00308-w