European mink (Mustela lutreola) - De Zoogdiervereniging

Photo 2. The second European mink in the live trap. Photograph: Addy de Jongh.Photo 3. The frozen road victim from the Dniester delta. Photograph: Tjibbe de Jong.Ukraine a European mink road victim was found(photo 3), indicating that a population of minkexists in that area as well.Recent introductions of the American mink(Mustela vison) in the Danube delta are believedto have caused population declines and local extinctionsof European mink. Males of the Americanmink are able to mate early with Europeanmink females producing resorbed hybrid offspringand could prevent successful reproductionin European mink (Ternovskij & Ternovskaya1994). American mink is more aggressive andproduces more offspring in a single season.Studies with radio telemetry on both mink specieshave indicated that European mink may bechased away from its home range by invadingAmerican mink (Sidorovich 1997). The combinationof these two factors has been suggestedto have contributed to the decline of Europeanmink populations (Maran 2007) (figure 2).To assess the risk for European mink in theUkrainian part of the Danube delta, we questionedtrained foresters in the area. In the Soviettime, there was an American mink fur farm in theneighbouring city Izmail. After the collapse ofthe Soviet system the fur farm was dismantled.50 De Jongh et al. / Lutra 2007 50 (1): 49-52

Figure 1. Locations in the Danube delta where bothEuropean mink were trapped.The foresters suggested that it was unlikely thatany of these animals survived, and could showthat only European mink were seen in the area.A biologist specialised in the Dniester ecosystemalso confirmed that European mink wereliving in this delta, but very low numbers werethought to occur (N.V. Rozhenko, personal communication).The pelt of a European mink caughthere at the end of the 20th century indicated thatEuropean mink occurred in this delta around tenyears ago. There were no indications of Americanmink in this area. A decline in the Europeanmink population was thought to be the result ofa newly constructed dam on the river Dniester(further north in Moldova) which regulates thewater level and negatively influences the mink’shabitat. The dam mainly reduced fluctuations inwater levels of the river, negatively affecting thefood resources of the European mink (N.V. Rozhenko,personal communication).We will continue research in both deltas, withthe aim of enhancing our understanding of theoccurrence and population size of Europeanmink. Depending on our findings, a telemetrystudy will be set up to improve our knowledgeabout home ranges and daily activities of thisspecies. A rescue plan for the survival of the Europeanmink in this region needs to be developedurgently.Acknowledgements: We thank Alexander Voloshkevych,director of the Ukrainian Danube DeltaBiosphere Reserve, for his hospitality, help and advice.We also thank the foresters of the reserve for theircompany, friendship and willingness to cooperate. Weare grateful for the important input of Mr. Tokar senior,the father of one of the authors, for his rapid andprofessional construction of the live traps. Last but notleast, we are grateful for the equipment and adviceprovided by our Irish colleague Lughaidh Ó Néill.Figure 2. The historical and present geographicdistribution of the European mink. Note the releasedpopulations on the large Estonian islands of Saaremaaand Hiiumaa.ReferencesKranz, A., A. Toman, Marinov, M. & J.B. Kiss 2004.European mink research: Results of the spring2004 expedition. Scientific Annals of the DanubeDelta Institute for Research and Development,Tulcea – Romania 2005: 42-44.De Jongh et al. / Lutra 2007 50 (1): 49-52 51