In 1905 a Count from the Czech Republic took from a hunting trip in Canada a few muskrats which he left free in the ponds on his estate. The muskrats began reproducing in a high speed and started to spread across Europe. From the thirties of the last century in the Netherlands there was feared for the coming of the muskrat. The animal was known as a formidable graver and could be a threat to the country.
A large part of Netherlands lies below sea level which makes good dykes essential.
In 1941, in the South of the Netherlands the 1st muskrat was caught. In 1945 it was decided to establish an organization in Netherlands that was responsible for the trapping of muskrats.
The majority of muskrat in the Netherlands are living in underground burrows. The access to the burrows are under water making it for the natural enemy difficult to penetrate.
All burrows have a similar floor plan. They consist of one to more access pipes that are starting under water and are leading to a nest Chamber. The nest Chamber is so high in the Bank that is stays dry. In that nest chamber the muskrat lives and gives birth to their litters. Some have also build an air pipe. The air pipe runs from the nest Chamber upwards to the surface. Air pipes are usually stuffed up with a prop plant material. Young muskrats use the air pipes to go aboveground for foraging
Muskrats propagate rapidly. Netherlands muskrats in average are having three litters each year. The number of young animals per litter ranges from 1 to 12, the average is 6. The 1st litter usually is born in the period april to early May. The second litter in June/July and the 3rd around August. Young females of the 1st litter are getting their first litter in the autumn of the year they are born. So the reproduction is in an enormous speed. Take the given that 1 pair muskrats are in average moving 1 cubic meters of sand per year you can imagine what problems this may pose to the safety of Dutch citizens.
- COMBAT ORGANIZATION IN NETHERLANDS
In the Netherlands the 25 water boards are responsible for combating the muskrat and coypu. Various water boards entered into partnerships which led to 8 control organizations in the Netherlands.
Combatting the muskrat and coypu is a legal responsibility of the water boards and their trappers are engaged throughout the year to keep the population as low as possible. They have the Government’s permission to carry out their activities everywhere (also on private areas)
In total, in the Netherlands there are 400 full-time employed trappers employed by the waterboards, they all have a civil status.
Combating the muskrat and coypu costs 35 million euro’s per year in Netherlands.
The Netherlands is divided into approximately 450 trapping areas. Every trapper is responsible for his own trapping area (s). There is regularly worked intensively with other trappers for trapping larger areas.
The coypu is well under control in the Interior of the country and the trapping happens along the borders by specialized coyputrappers.
- CAPTURE STRATEGY
The muskrat has two periods per year in which it migrates:
- Spring Migration (February to end of April):
-by changing water depth: transition from winter to summer levels
-search for own territory
-search for partner
- Autum Migration (September to November):
-social tensions between the boy and the older animals
-composition and density of the population
-possible formation of new parent couples
-shortage of food
-quest for deeper water to reserve the possibility to continue to move under the ice
The trappers in the Netherlands make intense use of this migration periods.
- During the migration periods in all watercourses drowning- and baittraps are used to catch the muskrats that are on the move.
- Between the migration periods all watercourses are checked by the trappers for the presence of muskrats, in these periods there is intensive use of clamps.
- TRAPPING RESULTS
The structured and professional approach is successful is the Netherlands. The population is starting to get under control and the number of trapped muskrats sits in a descending line.
In the graph below which shows the number of catches per week over the last 3 years is clearly visible the spring and autumn migration.
Henk vd Steen
and Dolf Moerkens