Ban on crayfish fishing in lake Tyrifjorden and lake Steinsfjorden 

To prevent the spread of crayfish plague, the Norwegian Food Safety Authority (Mattilsynet) has established restriction in parts of the Drammen watercourse system, including Lake Tyrifjorden and Lake Steinsfjorden and their tributaries. All crayfish fishing within the crayfish plague restriction zone is prohibited as of July 30, 2026.

No Crayfish Fishing This Year

This means that this year's crayfish fishing season has been cancelled. All crayfish fishing in Lake Tyrifjorden and Lake Steinsfjorden, as well as in rivers and streams covered by the restricted zone, is prohibited.

The following activities are prohibited:

1. Catching live crayfish, collecting dead or live crayfish, or keeping crayfish in traps or pots within the protected zone.
2. Moving live or dead freshwater crayfish within the protected zone.
3. Introducing live crayfish or other aquatic organisms into the protected zone.
4. Removing live or dead fish and other aquatic organisms that may carry the infectious agent from the protected zone. This prohibition does not apply to aquatic organisms other than freshwater crayfish that are intended directly for consumption.
5. Removing untreated waste or unprocessed products from fish and other aquatic organisms from the protected zone.
6. Transporting untreated water out of the area or upstream within the protected zone.

The following measures are mandatory:

1. Fishing gear, boats, construction machinery, water containers, and any other equipment or tools used within the area must be thoroughly dried and disinfected before being used outside the area. Within the area, the same measures must be taken if such items are removed from the water before being moved upstream.
2. Any findings of dead or diseased crayfish must be reported to the Norwegian Food Safety Authority (Mattilsynet).

The full regulation can be found on the Mattilsynet website.

Who Does the Restricted Zone Regulation Apply To?

The restricted zone regulation affects businesses and private individuals engaged in fishing and trapping activities within the designated area, as well as others carrying out activities that may contribute to the spread of infection.

The regulation imposes restrictions on activities within the zone to prevent further spread of the disease.

Everyone using waters and waterways within the protected zone is responsible for preventing the spread of infection to other watercourses.

Background

Crayfish plague is a serious and highly contagious disease affecting crayfish. It is caused by the water mould Aphanomyces astaci. The disease is fatal to the European noble crayfish and therefore represents a severe threat to this already endangered species.

Important Information for Everyone Using the Lake

Everyone spending time on or near the lake is strongly encouraged to take precautions to prevent the spread of crayfish plague. Proper handling of equipment is essential to reduce the risk of transmission.

Parasites, bacteria, and the spores that cause crayfish plague can survive in damp environments for several days. They can be spread through fish, fishing equipment, canoes, kayaks, and water from infected watercourses and facilities.

Always dry and disinfect fishing gear and other water-sport equipment before moving it between waterways or between different parts of the same watercourse. This is extremely important.

Violations of these regulations are punishable by law.

How to Disinfect Equipment

You can disinfect your equipment yourself, including fishing gear.

1. Use an approved disinfectant, such as Virkon S (available from agricultural suppliers and other retailers).
2. Prepare a 1% Virkon S solution by dissolving the powder in water.
3. Apply the solution to the equipment and leave it for approximately 15 minutes. Rinse thoroughly afterwards.

Virkon S is generally gentle and will not normally damage equipment.

Always follow the manufacturer's instructions.

Further guidance on disinfecting equipment, including kayaks and crayfish traps, is available from Mattilsynet Lenke til et annet nettsted, åpnes i nytt vindu..

The Regulation

On 30 July 2026, the Norwegian Food Safety Authority (Mattilsynet) adopted regulations establishing a restricted zone for the control of crayfish plague in the Drammen watercourse system.

Main Provisions of the Regulation

1. The purpose of the regulation is to control and combat crayfish plague within the area covered by the regulation.
2. The protected zone includes the municipalities of Modum, Krødsherad, Drammen, Lier, Ringerike, Jevnaker, Hole, Øvre Eiker, and Sigdal in the counties of Buskerud and Akershus.

Questions?

• The restriction regulation, supporting documents, and information about crayfish plague, equipment disinfection, and related measures are available on the Mattilsynet website.
• The municipality will continue to communicate new information as it becomes available but has no formal role in managing the outbreak. If you have questions that are not answered elsewhere, please contact Environmental Advisor Miriam Geitz at miriam.geitz@hole.kommune.no.
• If you are a crayfish fisher and have questions regarding crayfish fishing, please contact Steinsfjorden Fishery Association at steinsf@steinsfjordenfiskeforening.no.

Relevant websites:

• Prevent the Spread of Disease During Fishing, Trapping and Travel in Freshwater Waters Lenke til et annet nettsted. | Mattilsynet (in Norwegian)
• Crayfish Plague Lenke til et annet nettsted. | Mattilsynet (including posters that can be printed and distributed locally) (in Norwegian)
• Crayfish Plague Confirmed in the Drammenselva River in Modum Municipality, Buskerud County – All Crayfish Fishing in the Area Is Prohibited Lenke til et annet nettsted. | Mattilsynet (in Norwegian)

This text has been translated with the help of AI.