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Signal crayfish in Lake Saimaa could be maladapted to the local conditions due to Aphanomyces astaci infection: a seven-year study
Jussila J, Tiitinen V, Edsman L, Kokko H and Fotedar R 
Published Online: 11/2/2016
Abstract
We conducted a seven-year survey (years 2009 - 2015) of the Lake Saimaa signal crayfish population. Lake Saimaa is the largest single waterbody in Finland, with a productive fishery and crayfishery. The signal crayfish were introduced to Lake Saimaa in mid-1990’s and a commercial fishery was initiated in the mid-2000s. At first, there was a small proportion of noble crayfish among the catch, but after 2007, an acute crayfish plague epidemic eradicated them, and the signal crayfish stock started showing frequent gross symptoms of chronic crayfish plague infection (e.g., melanised lesions, eroded uropods and pleopods, lost appendages with melanised stumps). This stock now shows gross symptoms of the infection at a rate of 45% to 79% of the annual trap catch, in addition to showing signs of eroded swimmeret symdrome (ESS) at a rate of 2.8 to 15.4%. The CPUE has remained rather low, between one and three crayfish throughout the survey, while the proportion of the commercial grade catch has been between 35% and 68% of the total catch. The signal crayfish populations in Lake Saimaa are still rather fragmented, and production is low. It appears that the Lake Saimaa signal crayfish population has developed slowly and is producing less than expected.
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How to Cite
Jussila J, Tiitinen V, Edsman L, Kokko H and Fotedar R. (2016). Signal crayfish in Lake Saimaa could be maladapted to the local conditions due to Aphanomyces astaci infection: a seven-year study. Freshwater Crayfish 22(1):53-60. doi: 10.5869/fc.2016.v22-1.53
Author Information
Japo Jussila,* Department of Environmental and Biological Sciences, University of Eastern Finland, P.O.Box 1627, Kuopio, Savo, Finland70211. E-mail: japo.jussila@uef.fi
Vesa Tiitinen, N/A, South Karelian Fisheries Advisory Center, Hietakallionkatu 2, Lappeenranta, Karjala, Finland53850. E-mail: vesa.tiitinen@ekkalatalouskeskus.fi
Lennart Edsman, Department of Aquatic Resources, Swedish University of Agricultural Sciences, N/A, Drottningholm, Stockholm, Sweden17893. E-mail: lennart.edsman@slu.se
Harri Kokko, Department of Environmental and Biological Sciences, University of Eastern Finland, P.O.Box 1627, Kuopio, Savo, Finland70211. E-mail: harri.kokko@uef.fi
Ravi Fotedar, Environment and Agriculture, School of Science, Curtin University, Kent Street, Bentley, Western Australia, Australia6102. E-mail: r.fotedar@curtin.edu.au
Corresponding Author indicated by an *.
Publication History
Manuscript Submitted: 6/6/2016
Manuscript Accepted: 10/11/2016
Published Online: 11/2/2016
Published in Print: 12/31/2016
Funding Information
No specific funding statement is available for this article.