Muskrats trapped in Friesland after positive eDNA sample

In August/September 2021, 3 muskrats were caught in Friesland thanks to eDNA. It concerned an area with a low muskrat population.

Tracking down muskrats and coypu can be made easier by detecting the DNA they leave behind in the water. This DNA is called environmental DNA (eDNA) and comes from, for example, intestinal cells in faeces.


In this case, a 5 km section between the towns of Bolsward and Hartwerd turned out to be positive. Subsequently, 1 km sections were sampled, of which 1 was positive for muskrat eDNA. Afterwards point samples were taken.

Feed traces

During point sampling, the muskrat trappers found some questionable feed traces. These did not directly indicate a muskrat, but could also have come from a water vole. Thanks to the eDNA the muskrat trappers knew that muskrats had been present, so they so they carefully scanned the water’s edge. There was indeed a muskrat burrow. This is how the first muskrats of 2021 were trapped in this area.

Caught muskrats between Bolsward and Hartwerd

A. In red, positive 5 km route;
B. In red, positive 1 km localization section;
C. Localization point samples. Red: highest positive concentration, orange: moderate positive, green: negative. Arrow: location of the trapped muskrats. At the second red dot at the top, the water was too deep;
D. The trapped muskrats.

Latest progress in development Smart Life Trap: first catch

This project aims to develop smart life traps that use image-recognition. Thus we prevent unwanted bycatches of protected species as European beaver or otter and only catch target species like coypu and muskrat. Recently we made good progress on the Smart Life Trap project. The first catch was made in the field.

Image-recognition is dependent of many pictures; we received lots from the field. Thanks to people from the regional water authorities and volunteers from zoos as well.

New model

A new model was made and tested. Overall the new model already makes good predictions. The Artificial intelligence specialists made a model that is quite accurate. Below is a ‘confusion matrix’. It shows the number of accurate predictions: mainly correct ones. It predicts ‘Rat group’ when it is actually a ‘Rat group’ indeed and the same with birds and the ‘Others group’ category. However, it still made some incorrect analysis. This was improved in the last months of 2021, with new photos from the field.

Real life tests and results

Below are photos with a ‘heatmap’ overlay. The more yellow/red the image is, the more this part of the picture was used for recognition. We can see from the photos that it concentrates mainly on the actual animal even when other objects like leaves or food are in the picture as well. And recognition succeeds at night as well.

Many images

In the past months we also succeeded in entering many images of otters and beavers, with the help of a German otter centre (Otter-Zentrum Hankensbüttel) amongst others. This will make the model even more accurate, even when animals look like the target species but are different.


The camera was built into 5 traps and tested in different settings, day and night. The first actual catch in the field occurred in December: a muskrat. As a control set-up, we use 24h wild game camera’s to observe the test traps and the animals entering it.

50 Smart Life Traps

In the first months of 2022 a total of 50 Smart Life Traps will be deployed across national borders: Germany (20), Belgium (5) and the Netherlands (25).

Dragonflies and damselflies as indicators for biodiversity

The month of June was dominated by dragonflies and damselflies for the Life MICA employees of the Institute for Nature and Forest Research (INBO). An important part of the Life MICA project is monitoring biodiversity in the project areas.

This data can help to estimate the impact of muskrats, coypu and their impact on nature. In Flanders, birds, plants and dragonflies are monitored in the De Luysen nature reserves in Bree (Limburg) and in the East Flemish creek area in Sint-Laureins.

9 species of damselflies

The first monitoring on 2 June took place under ideal weather conditions in the Luysen. We immediately observed a large number of species along the transects. We saw 9 species of damselflies, including the variable damselfly, the white-legged damselfly, the common winter damselfly and the Large Redeye damselfly.


It was also clearly the peak of the flight time of the glass cutter, which flies unobtrusively among the reeds. We also saw the brown corn bolt whose males are on the lookout for the reeds. In total we saw 7 species of large dragonflies in this swamp area, including the Blue Emperor dragonfly. On subsequent visits, we were able to add several more armored spread-winged damselflies to this list. We also saw large numbers of Ruddy Darter.

The dragonfly monitoring is over for this year. We are already looking forward to next year!

Raccoon detected with camera trap

It is clear that camera traps are useful for tracking muskrats and coypu. The Life MICA partners have already collected more than 2000 images of muskrats. More than 1000 coypu were also captured on image.

A nice advantage for the muskrat control is that other invasive species can also be seen on the camera images. A raccoon was spotted in the De Luysen area (Limburg, Flanders) in May. The raccoon is already widespread in Europe, but in Flanders the species is still on the rise and often remains under the radar.

Circulation of muskrats and coypu

Images like these can help to map the circulation of muskrats and coypu. They also can help with targeted management of the species.

Searching and catching in Sint-Laureins

The landscape of creeks and polders in the border municipality of Sint-Laureins houses the last large population of muskrats in East Flanders. It is important to continuously monitor this area to avoid expansion and to reduce the species.

In 2021, the Flemish Environment Agency (VMM) started its control campaign here with the spring migration of muskrats at freezing temperatures. These migratory muskrats are often difficult to catch.

324 muskrat catches

During summer traces are very different. Territories are marked and plenty of food remains can be seen. Six months of hard work, aided by observations of 10 camera traps, yielded 324 muskrat catches. 195 of these were captured within the contours of the Life MICA project area.

Next control campaign

As soon as the high summer levels in the polder drop again, the VMM is organizing a next control campaign in the area.

First virtual Open day at the project site Aschauteiche

Raising awareness on invasive alien species – a focus of MICA

The MICA project is dealing with the management of two invasive alien species, coypu and muskrat, and therefore intends to raise public awareness on this subject. During the course of the project, several communication events, such as open days, are organized. Due to the coronavirus pandemic, some of those public events had to be cancelled or postponed.

It was originally planned to welcome different stakeholders and interested public for open days in the 11 project areas (in Germany, the Netherlands and Belgium) in order to introduce them to local project activities, to discuss about the project progress and receive suggestions for improvements. However, facing ongoing restrictions for public events and considering the safety of the participants, we decided to set up our first open day for the project area Aschauteiche as online event using Microsoft teams.

The German project site Aschauteiche

The German project site Aschauteiche, close to Eschede in the municipality of Celle, is a sustainable fishpond cultivation comprising near-natural lakes. The project site is part of a FFH and EU-bird protection area and home to several protected species. About a decade ago, coypus established at the lakes and, recently, the fish otter settled there as well. At this site, the Life MICA project intends to assess the impact of coypus on biodiversity and to test intelligent live traps closing only for target species like coypus.

The first virtual open day at Aschauteiche

The event took place on July 2nd 2021, when stakeholders from the local nature conservation office, the mayor of Eschede, the hunters association, a nature conservation organization, the Otterzentrum Hankensbüttel, members of the Agricultural Chamber of Lower Saxony and interested public participated in the event.

After a general introduction to the Life MICA project, we presented a short film (in German) about our activities at the project site and the characteristics of the area.

Helge John, employee at the fishpond cultivation and member of the hunters association, offered an interesting insight into the history of the Aschauteiche and the local occurrence and management of coypu populations as well as protected bird species. Furthermore, we had a great guest contribution from Martin Brühne, project leader from Reeds-for-Life (, about coypu management in the nature conservation area Bienener Altrhein and the successful replantation of reed vegetation to recover the damage caused by coypu during the past years.

A total of 21 persons participated in the event and several topics ranging from live trapping to the impact of coypus on biodiversity were lively discussed. In general, the feedback from the participants was very positive, highlighting once again the importance of communicating with different stakeholders and related projects about the problematic of invasive alien species.

Outlook for 2022

In 2022, we hope to be able to welcome interested stakeholders in person at the project site!

Watch: Life MICA event of February 9, 2021

On February 9, the Life MICA project organized a webinar. This webinar looked back on the first year and a half of the project. What have we done so far and what have we learned from it?

Watch webinar

To log in, use the email address

Enjoy watching!

9 February: Webinar Life MICA

Life MICA is an EU Life project with the aim to reduce and manage muskrat and coypu populations in order to prevent damages to dikes, biodiversity and crops in Europe. Institutions from Belgium, Germany and the Netherlands work out a number of best practices and develop new techniques for a more efficient muskrat and coypu control.

The Life MICA project has now been running for 1.5 years. During this project we are assisted by a project board.

We would like to invite you to a varied online event on Tuesday 9 February at 10:00 hrs. During this event you will hear all about the knowledge we have gained, we will tell you where we are now and what to expect. There is plenty of room for questions and discussions. We are looking forward to meet you.

> Attend the webinar

Coypu and muskrat – a threat to biodiversity?

With the increasing spread of coypu and muskrat, their harmful effects become the focus of attention. Both species dig tunnels and burrows on embankments and feed on aquatic vegetation, damaging mainly reed plants like reed and bulrush. Reed vegetation constitutes the habitat of numerous animal species: birds such as the great bittern or the reed warbler breed here and migratory birds look for resting places on their transit in reeds. Different species of fish spawn in the reed beds, where juvenile fishes can find protection from predators thereafter. Furthermore, various insects, including many dragon- and damselflies, depend on reed plants.

Coypu and muskrat can massively damage reed vegetation through their burrowing and feeding activities and thereby compromise the habitat of numerous protected animal species.

A coypu feeding on the floating blade zone at Lake Dümmer

As part of the MICA project, the effects of coypu and muskrat on biodiversity are being investigated. For this purpose, mapping of aquatic vegetation, bird populations and dragonflies is carried out several times a year in the project areas and compared with data on the occurrence of coypu and muskrat (hunting statistics and camera trap monitoring).

Aschauteiche (German project area no. 2)
Abandoned channel of Vechte in Grafschaft Bentheim (German project area no. 3)
Lake Dümmer (German project area no. 1)

The Institute for Terrestrial and Aquatic Wildlife Research of the University of Veterinary Medicine Hannover and the Agricultural Chamber Lower Saxony carried out the first field mapping of the aquatic vegetation and dragonfly species in the German project areas in August and September this year.

Vegetation mapping at Lake Dümmer
Damselfly mapping at Aschauteiche
Dragonfly mapping at Aschauteiche

Kick-off “Alien Species – a discourse”

With increasing awareness of the society for the problem of invasive animal species, ethical issues concerning how to deal with these animals also come into focus.

The Institute for Terrestrial and Aquatic Wildlife Research participates in this dialogue with a public relations project that is funded by the Ministry of Science and Culture of Lower Saxony as part of the program Future Discourses. With the project title “Alien species – a Discourse: how do we deal with introduced species, and how do we want to deal with them in the future?” the issue of ethics has already being faced. The project aims to establish a dialogue between different interest groups and shed light on society´s attitude towards invasive species.

The kick-off event took place on September 24, 2020 at the University of Veterinary Medicine Hannover, in compliance with hygiene regulations in effect. Teachers and interested citizens were invited additionally to representatives from research, hunting, water associations, nature conservation organizations and politics. Partners from the German project areas of the Life-MICA project took part as well.

After short initial presentations, in which the opinion of the individual stakeholders were presented, there was an active discussion on various conflict topics, as for example: the conflict about the repartition of responsibilities between hunting and pest control, the problem of by-catches of protected species by trapping and the lack of awareness in the society for the threats imposed by invasive species. A further deepening of certain discussion contents and the development of a questionnaire will represent the next steps towards an impulse paper with which the project aims to raise a question mark. The topic of neozoa will be also made accessible to young people. For this purpose, a workshop box with exercises and illustrative material on the subject neozoa was prepared and will soon be worked on by students from different regions in Germany. Moreover, an informative short film on the subject of neozoa was made.

Additionally, you can find the recording of the event here.