Crayfish plague (Aphanomyces astaci)
The Norwegian Veterinary Institute (NVI) conducts crayfish plague surveillance in control areas, combat zones and risk areas.
The purpose of the program is to monitor the infection pressure and infection development in control areas and combat zones for Aphanomyces astaci, and to substantiate disease freedom and/or provide an early warning of possible infection spread in to risk areas
In 2018, A.
- In the control zone of the Halden watercourse, A.
astaci eDNAwas only detected in the southern part of Lake Rødenessjøen. Here, the known presence of signal crayfish was confirmed by eDNAdetection. No sign of crayfish plague was observed in the northern part of Lake Rødenessjøen (Kroksund) up to the control zone border at Fosserdam. This result was supported by positive detections of noble crayfish eDNAin all water samples from River Hølandselva and upstream. All water samples in this risk area were negative for A. astaciand signal crayfish, while most samples were positive for noble crayfish eDNA.
- In the Mosse watercourse, no
eDNAof A. astacior signal crayfish was detected. However, one dead crayfish found in Lake Langen was positive for A. astaci, demonstrating that crayfish plague has spread into Lake Våg and Lake Langen. Noble crayfish eDNAwas detected at the inlet of Lake Langen.
- In the Glomma watercourse, no sign of crayfish plague was found, and the samples were negative for all screened targets.
- In Eidskog municipality, no samples were positive for either signal crayfish or A.
astaci, while several were positive for noble crayfish eDNAin River Vrangselva and River Finnsrudelva.
- Aphanomyces astaci 2018 (pdf 8mb)