Mutation Research 628 (2007) 19–30 Genotoxic damage in field-collected three-spined sticklebacks (Gasterosteus aculeatus L.): A suitable biomonitoring tool? Gertraud Wirzinger a,∗ , Lennart Weltje b , Jens Gercken c , Holmer Sordyl c a University of Applied Sciences Zittau/G¨ orlitz, Theodor-K¨ orner-Allee 16, D-02763 Zittau, Germany b J.W. Goethe University, Department of Ecology and Evolution–Ecotoxicology, Siesmayerstrasse 70, D-60323 Frankfurt am Main, Germany c Institute for Applied Ecology, Alte Dorfstrasse 11, D-18184 Neu Broderstorf, Germany Received 25 November 2005; received in revised form 9 October 2006; accepted 12 November 2006 Available online 8 January 2007 Abstract Three-spined sticklebacks (Gasterosteus aculeatus L.) were collected during different sampling trails from three locations in Northern Germany, which differ in the amount of sewage-treatment effluent that they receive. Due to natural population developments, the size of the specimens caught decreased significantly from April to August. The fish were examined for DNA damage in their blood cells by means of the comet (single-cell gel electrophoresis, SCGE) assay and the micronucleus test (MT). The suitability of stickleback erythrocytes as indicators for genotoxic substances in water was assessed. The median level of strand breakage ranged from 5.23 to 9.67%, and decreased significantly from April to August. The difference between the locations was marginally significant. The amount of micronuclei was more variable (ranging from 0.40 to 4.35%), but appears to better reflect the pollution state of the sampling location. Significant differences between the locations were found. The relatively strong micronucleus induction found in this study may be related to the fish species selected. Contrary to the SCGE results, a significant increase in the number of micronuclei from April to August was observed. A significant negative correlation between strand breakage and micronuclei was found for the sticklebacks from the most polluted location and for the pooled data of all locations. The length of the fish was positively correlated with results of the SCGE and negatively with those of the MT, whereby males show a clearer relation between size and the amount of genotoxic damage. The test results are predominantly affected by seasonal impacts. This study indicates that the outcome of the SCGE and MT applied to sticklebacks is determined by multiple factors, which need to be identified first before these tests can be applied routinely. Because of the profound negative correlation between SCGE and MT results, we recommend to apply both tests for the evaluation of the genotoxic potential of surface waters. © 2007 Elsevier B.V. All rights reserved. Keywords: Comet assay; Micronucleus test; Genotoxicity; Blood cells; Stickleback; Field monitoring ∗ Corresponding author. Present address: J.W. Goethe University, Department of Aquatic Ecotoxicology, Building A, Siesmayerstrasse 70, D-60323 Frankfurt am Main, Germany. Tel.: +49 69 79824900; fax: +49 69 79824748. E-mail address: wirzinger@bio.uni-frankfurt.de (G. Wirzinger). 1. Introduction As many chemicals with genotoxic potential are emitted to surface water through municipal and indus- trial waste water effluent, genotoxicity tests are gaining importance. The detection of pollution is increas- ingly achieved by the use of bioindicators (species or biocoenoses which react sensitively to stress in the envi- ronment) as they tend to accumulate pollutants, thereby 1383-5718/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.mrgentox.2006.11.011