The species occasionally hybridizes with Mustela putorius (Tumanov and Abramov 2002). Genetic studies have shown that the western populations (Spain and France) have very low genetic variability and southern populations show moderate genetic variability, whilst the eastern populations have the greatest variability (Lode 1999; Davidson et al. 2000; Michaux et al. 2004, 2005).

Critically Endangered (A2ce). This assessment refers only to the isolated population in Spain and France. The French population is declining rapidly. In Spain the overall number of European mink is decreasing, and the species is disappearing from rivers in the north and centre of its range, although a concurrent slight extention of the range to the east has been observed (Palomo and Gisbert 2002). The rate of decline has not been quantified, but an 80% reduction in the past ten years seems reasonable. The species could well become extinct in France in the near future, but probably not in the next ten years.

Mustela lutreola is largely restricted to Europe. A century ago it was widespread throughout the continent, with a distribution extending from northern Spain in the west to the river Ob (just east of the Urals) in the east, and from the Archangelsk region in the north to the northern Caucasus in the south (Youngman 1990). However, over the last 150 years it has severely declined and been extirpated or greatly reduced over most of its former range (Maran 1999). The current range includes an isolated population in northern Spain and western France, which is widely disjunct from the main range in Eastern Europe (Latvia, Estonia, Belarus, Ukraine, central regions of European Russia and the Danube delta in Romania). It occurs from sea level to 1,120 m (Palazon et al. 2003).

Since the mid-19th century, this species has undergone dramatic declines throughout its range, and is now extinct in most European countries. It now occupies less than 20% of its original range, and the remaining population is small and fragmented and continues to decline (Maran 1999). Recent population estimates include 500-1,000 individuals in Spain (Palazon et al. 2003), several hundred individuals in France (Fournier and Maizeret 2003, Stephane Aulagnier and Roland Libois pers. comm. 2006), and <1,000 individuals in the Danube Delta (A. Kranz pers. comm. 2006). In Ukraine, at the beginning of the 21st century, the population was estimated at 350-400 individuals, with the majority of those found in the Danube Delta (>200 individuals) (Volokh 2004). The most viable population in western Europe is that of the Danube Delta, but even this population may be rapidly declining: in 250 trap nights (2006) only one animal was caught, compared to one in 20 nights in 2003 (A. Kranz pers. comm. 2006). Other viable populations are found in the northeastern part of European Russia.

The current European mink range in Russia consists of isolated distant habitats of different size. These fragmented populations are scattered across western Russia, the Urals, and the northern Caucasus. The only parts of the range where the American mink is absent are rivers in the Archangelsk Region and Komi. Everywhere else populations of European mink are vanishing or becoming increasingly fragmented and localised, and in a greater part of historical range in Russian the European mink is not met any more. The Russian population of European mink has been estimated at c.20,000 (Tumanov 2003, 2006), but this is not based on quantitative data as no large-scale census has been done. Hunting bags suggest that the European mink is rapidly becoming less abundant by comparison with the American mink: for instance, in Vologda and Kostroma regions the proportion of European mink skins in the hunting bag of the two mink species decreased from 50-70% to 1-10% within the last 5-7 years (to 2006). For the whole of Russia, recent records refer only to the capture of single individuals or to local populations consisting of some ten of individuals (Skmatov and Saveljev 2006).

European mink have specialised habitat requirements. They are semi-aquatic, inhabiting densely vegetated banks of lakeshores, rivers, streams and marshlands, and are rarely found more than 100 meters away from fresh water. They forage at night, hunting both on land and in water for a wide range of animal prey including small mammals, birds, frogs, molluscs, crabs, fish and insects (Youngman 1990, Maran 1999, Palomo and Gisbert 2002). Females become mature at 19 months (Youngman 1990).

Habitat loss and degradation is a serious threat to the European mink. Ongoing destruction and degradation of freshwater and associated terrestrial habitats is caused by by inter alia hydroelectric developments, channelisation and water pollution. Accidental trapping is also a threat, even though the fur of the European mink is less valuable than that of the American mink Neovison vison. In France, secondary poisoning and trapping of European mink has occurred as a result of efforts to control coypu (Myocastor coypus) and small carnivores (e.g. polecat). Accidental mortality through vehicle collisions is a problem in some areas, and small remnant populations may be driven extinct by threats such as predation by feral dogs and accidental mortality in fish traps (T. Maran pers. comm. 2006). Competition and direct aggression from the American mink is a further threat to depleted remnant populations (Maran 1999). The Aleutian disease could also have an impact, but diseased animals have not yet been found. In Spain and France, hybridization with Mustela putorius may be a threat (Davidson et al. 2000).

Legally protected in all range states (Schreiber et al. 1989) including the Russian Federation (Alexei Tikhonov pers. comm 2006). At least part of the population occurs within protected areas. Studies have been undertaken to determine the mink's ecological requirements, to analyse the causes of its decline, and to assess the genetic variability of western populations. In Spain and France programmes have been started to control the American mink population. A captive breeding programme was launched in 1992 by the European Zoo Association (the Catalonian Government's captive breeding programme is part of this European initiative). Efforts are being made to reintroduce European mink to areas where they formerly occurred in Germany and the Russian Federation. An introduction programme is underway on the island of Hiiumaa (to Estonia) in the Baltic, where the American species has been excluded. In France a national action plan for the conservation of the European mink was initiated by the Ministry of Environment and has been coordinated by the SFEPM (French Mammal Society).

Conservation needs vary throughout Europe, and include the following:
·National and regional authorities need to increase attention and allocate sufficient resources for European mink conservation. Otherwise this species will disappear soon.
·There is a need for large-scale efforts to secure the survival of the last small remaining populations in different areas inside of the historical range of the species, but also restoration and/or establishment of new populations is required.
·For remaining in situ populations, the maintenance or restoration of sufficiently large areas of suitable habitats has to be secured by designation of new protected areas and improvement of management of existing protected areas.
·The impact of the American mink on local European mink populations has to be monitored and controlled, and whenever possible and feasible the alien mink populations should be removed. Local authorities have to pay more attention to the effects of the American mink on the local fauna, including the European mink. They should support further studies and actions to mitigate the effect of alien mink to the native mink species.
·Aleutian diseases and other pathologies must be monitored in all remaining in situ populations of the European mink.
·For French and Spanish wild populations which appear to be highly inbred further research needs to be carried out to identify whether these seemingly genetically highly uniform populations suffer from inbreeding depression. The introduction of individuals from ex situ stock from genetically diverse eastern populations has to be considered as a potential conservation measure, if further research confirms the need for this. In addition to genetic studies, comparative studies on ecology and behavior of the disjunct mink populations (Spanish/French, Romanian and eastern European) should also be conducted to support the findings of genetic studies.
·The ex situ conservation breeding program has to be enhanced and promoted, as it guarantees the survival of the species in case in situ efforts fail. It also provides opportunities for the restoration of already vanished wild populations and reinforcement of existing populations whenever needed.
·There is a need for developing an all-European conservation breeding program with secured long-term funding.
·Further studies are needed about the current the status of the European mink in Romania, Ukraine and elsewhere in eastern part of Europe.