Aims:
Diagnostic methods for confirming the presence of crayfish plague and population level sampling procedures for noble crayfish stocks will be tested and specified. This will form the basis of a standardised national guideline for determining the plague status of noble crayfish stocks. The guideline will enable the classification of noble crayfish waters in Finland. It will also help determine the use of such waters based on their crayfish plague status, for instance with respect to whether such waters require special protection, or can be made available for commercial utilisation. Classification can also ensure the safety of restocking in efforts to restore populations, while helping to identify waterways in which crayfish plague is chronic.
Results:
Guidelines for monitoring the health of noble crayfish stocks and policies for transfer and restocking.
Summary:
Crayfish plague research has revealed that crayfish plague does not always kill noble crayfish rapidly. Instead, they may become carriers and pass the disease on. This type of latent crayfish plague causes problems for the management of noble crayfish stocks and can contribute to the spread of signal crayfish, further narrowing the territories of noble crayfish. The project examines how crayfish plague manifests itself beyond the acute stage of the disease in different types of noble crayfish populations. Research is targeted to noble crayfish stocks, particularly in eastern and northern Finland, which have divergent crayfish plague histories and live outside the signal crayfish region. For the diagnosis of crayfish plague crayfish stocks are examined using the quantitative PCR method. Determining the population densities as well enables an assessment of the crayfish plague prevalence within each crayfish population and the number of samples required to detect the infection.
Keywords:
crayfish plague, crayfish plague prevalence, quantitative PCR, noble crayfish stocks, crayfish restocking, health monitoring
Responsible project leader:
Pelkonen, Sinikka, Head of Unit, Finnish Food Authority, Veterinary Bacteriology and Pathology Unit
Person at Finnish Food Authority responsible for the project:
Viljamaa-Dirks, Satu, Chief Specialist, Wild and Aquatic Animal Pathology Section
In cooperation with:
Natural Resources Institute Luke Crayfish research programme;
Norwegian Veterinary Institute
Project status:
In progress
Year of commencement:
2017
Year of completion:
2022
Publications:
Viljamaa-Dirks, S., Pursiainen, M., Mattila, J., Laakkonen, M.
Jokirapuistutuksilla on tulevaisuutta.
Suomen Kalastuslehti 2013: 3, s. 8-10.
Viljamaa-Dirks, S.
Crayfish plague genotypes and detection in wild populations of noble crayfish.
4th Annual meeting of the reference laboratories for crustacean diseases 1.11.-2.11.2012, Weymouth, England.
Lecture.
Viljamaa-Dirks, S.,Torssonen, H.,Heinikainen, S.,Pursiainen, M.,Rajala, J.,Mattila, J.,Laakkonen, M.,Partanen, T.,Sarajärvi, K.,Korhonen, P.
Rapurutto hallintaan II, 31 s.
RKTL:n työraportteja 17/2012.
ISSN 1799-4756
ISBN 978-951-776-921-1
Viljamaa-Dirks, S.
How to minimize the risk of the plague in crayfish population management.
Towards a responsible future in inland fisheries, EIFAAC 2012 Symposium 22.-24.10.2012, Hämeenlinna.
Abstract.
Working papers of the Finnish Game and Fisheries Institute 18/2012, s. 47.
Viljamaa-Dirks,S., Pursiainen, M., Heinikainen, S., Mattila, J., Rajala, J., Laakkonen, M., Pelkonen, S.
Surveying noble crayfish (Astacus astacus) populations for the presence of crayfish plague infection.
19th Symposium of the International Association of Astacology 27.8.-30.8.2012,Innsbruck, Austria.
Abstract.
Book of abstracts pp. 53.
Strand, D., Jussila, J., Viljamaa-Dirks, S., Kokko, H., Makkonen, J., Holst-Jensen, A., Viljugrein, H., Vrålstad, T.
Aphanomyces astaci spore dynamics in the ambient water of latent carrier crayfish revealed using qPCR.
19th Symposium of the International Association of Astacology 27.8.-30.8.2012,Innsbruck, Austria.
Abstract.
Book of abstracts pp. 52.
Strand, D.,Jussila, J.,Viljamaa-Dirks, S.,Kokko, H.,Makkonen, J.,Holst-Jensen, A.,Viljugreinn, H.,Vrålstad, T.
Monitoring the spore dynamics of Aphanomyces astaci in the ambient water of latent carrier crayfish.
Veterinary Microbiology 2012: 160, pp. 99-107.
Viljamaa-Dirks, S., Heinikainen, S., Nieminen, M., Vennerström, P., Pelkonen, S.
Persistent infection by crayfish plague Aphanomyces astaci in a noble crayfish population - a case report.
Bulletin of the European Association of Fish Pathologists 2011: Vol. 31, No. 5, pp. 182-188.
Kozubikova, E., Viljamaa-Dirks, S., Heinikainen, S., Petrusek, A.
Spiny-cheek crayfish Orconectes limosus carry a novel genotype of the crayfish plague pathogen Aphanomyces astaci.
Journal of Invertebrate Pathology 2011: 108, pp. 214-216.
Project financed by:
Ministry of Agriculture and Forestry (2531/311/2010);
Finnish Food Authoity;
Natural Resources Institute Finland (Luke)
Finnish Forest and Park Service
Finnish Food Authority project code:
8341