The Swiss Weekly Newsreel reported about the otter’s endangerment in 1952. Memobase

The last otter

Systematic hunting, changes in habitat and pollution are all contributing to otters dying out, as it says on the label describing an over 100-year-old prepared specimen on exhibit in the Naturama natural history museum in Aarau. The ‘end of the otter in Switzerland’ in 1990 is closely intertwined with the country’s economic history.

Claudia Aufdermauer

Claudia Aufdermauer is a freelance historian.

Switzerland’s last otter before the animal temporarily disappeared from the country in 1989 was to be found in Lake Neuchâtel. It is hard to say how many people knew about this rare creature at the time. The experts, especially an association that monitors otters closely, known as ‘Fischottergruppe Schweiz’, knew that the animal’s time in Switzerland was running short. In 1990, they wrote in a report to the Swiss Agency for the Environment, Forests and Landscape: “We will have to get used to Switzerland’s only otters being in zoos and museums.”

**Eurasian otter in Zurich zoo, 1985.** e-pics

The otter didn’t die out from one day to the next. People in Switzerland, whether knowingly or not, had long been contributing to the mammal’s demise. Industrialisation led to the building of canals, operation of water wheels, redirection of rivers, wetlands being dried out and waterways filling up with steamboats. Solid waste and sewage from factories and cities were discharged untreated into bodies of flowing water – so it could all flow into the sea, the world’s biggest storage tank.

There was a rethink in 1875. Certain species of fish were placed under national protection for the first time: factory sewage that was harmful to fish was banned, periods when it was prohibited to fish were introduced and fishing with dynamite forbidden. These actions were not prompted by animal lovers in the modern sense of the term. The official aim of the new legislation, the ‘Fischereigesetz’, was to double the annual income of the Swiss fishing industry, which was CHF 400,000 at the time. In keeping with the spirit of the law, hunters were also allowed to shoot otters.

**Hunter Rudolf Plattner poses with his catch, an otter in Reigoldswil, 1927.** Staatsarchiv des Kantons Basel-Landschaft, StABL PA 6281 02.01

Eradicating animals that consumed a lot of fish was seen as a way to boost fishing revenue. At the behest of the federal government, the cantons offered incentives to hunters: in 1891, a heron’s claw was worth CHF 6 in the canton of Zug, CHF 30 for an otter’s snout. The Federal Council considered these rewards too low in view of the “enormous damage inflicted by these predators on fish stocks”. So, the cantons increased their bounties.

In 1890, a hunter was praised for killing seven otters in the newspaper Geschäftsblatt für den obern Teil des Kantons Bern. At the same time, other hunters were encouraged to take up the lucrative killing of otters. — In 1890, a hunter was praised for killing seven otters in the newspaper u003cemu003eGeschäftsblatt für den obern Teil des Kantons Bernu003c/emu003e. At the same time, other hunters were encouraged to take up the lucrative killing of otters. e-newspaperarchives

The otter population eventually began to decline. By the mid-20th century, there were only about 100 of them left in Switzerland. Extinction seemed very much on the cards, even though it was no longer the objective. After the ‘Schweizerische Bund für Naturschutz’ (now Pro Natura) began lobbying in favour of the otter in 1917, a rethink gradually ensued at the federal level. The otter was officially named a protected species in 1952. However, their numbers continued to fall. Even attempted resettlements in the 1970s failed to reverse the decline.

So, what happened? Why did the protection measures not work? These were the questions ‘Fischottergruppe Schweiz’ tried to answer in 1990. It investigated why the translocation of otters during the preceding decades had not worked and concluded that it was not due to a lack of suitable living space, as numbers were falling all over Europe. The group was convinced that the only hypothesis that could explain the widespread demise of the otter in Europe was their being chronically poisoned by PCBs in their food supply.

**Illustration of the accumulation of poisonous substances in the food chain, circa 1979.** Ecology and environmental protection. A contribution by Swiss Re in Zurich to the discussion on the problem area “Ecology and the environment”

Polychlorinated biphenyls (PCBs) were used all over the world as industrial chemicals from 1930. In Switzerland they were used, for example, as insulating oils in transformers, as condensers in fluorescent tubes and as a supplement to joint sealing compounds. From an industrial perspective, PCBs have excellent chemical and physical attributes: they protect against strong acids, conduct heat, are only slightly soluble in water, extraordinarily heat resistant and chemically stable.

Due to their chemical stability, PCBs are not biodegradable. They gradually build up in the food chain as they are fat-soluble. This is known as bioaccumulation. PCBs are also thought to be carcinogenic and can be located all over the world. They have been found in children’s hair, sea eagles, fish and arctic seals. PCB bans have become increasingly widespread since the 1970s and Switzerland introduced a total ban in 1986.

As ‘Fischottergruppe Schweiz’ wrote, there was mounting suspicion that otters, who are at the end of the food chain, had become unable to reproduce due to a high PCB concentration in their body fat. Experiments with mink, which is closely related to the otter, had reportedly proven that. Given the high level of PBC contamination in Swiss waters, ‘Fischottergruppe Schweiz’ decided in 1990 that it wasn’t a good idea to expose more otters to those conditions, believing they had “no prospects of survival” in Switzerland at that time. Following the last otter’s passing in Lake Neuchâtel, ‘Fischottergruppe Schweiz’ spoke of the “end of the otter in Switzerland”.

For 20 years, otters were only to be found, at least in Switzerland, as exhibits in museums or swimming around in animal parks and zoos. The extent to which this loss of biodiversity was noticed by the public is not known. Since 2009, there have been some otter sightings. The foundation Pro Lutra, which is committed to bringing the otter back to Switzerland, thinks they made their own way back through the Rhone, Lake Constance, the river Inn and Lake Maggiore.

**There have been sightings of otters in Switzerland in recent years. The map charts them between 2020 and 2025.** Pro Lutra

What does the return of the otter tell us about PCB contamination in Swiss waters? The Federal Office for the Environment says PCB concentrations have become less concentrated in the air, soil and surface water sediment since the total ban. However, they have not disappeared completely either. The remaining sources need to be identified, incrementally removed and professionally disposed of. The importance of doing so was demonstrated in 2016 when BCP particles from the corrosion protection coat on the Punt dal Gall dam were released into the river Spöl during maintenance work. This river flows through the Swiss National Park. Four years later, a dead eagle-owl was found in the park with an extremely high PCB content. Following these events, the PCB accumulation in the Spöl and in less contaminated waters is to be examined and compared from 2025. The results will provide information about the contamination and decontamination of the different water systems.

Contaminated Switzerland

There are not many studies of the downside of industrialisation. Claudia Aufdermauer helps restore the balance with her book 'Vergiftete Schweiz. Eine andere Geschichte der Industrialisierung'. She presents an environmental history of industrialisation focusing on the 19th and early 20th centuries – and the effects that are still with us today.

More of: Modern Age 20th / 21st century Economy Nature

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