Signal crayfish are susceptible to crayfish plague infection under physiological challenge

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Aydın H., Kokko H., Jussila J.

Regional European Crayfish Meeting –CrayCro, September 26-28, 2013 Rovinj, Croatia, Pula, Croatia, 26 - 28 September 2013, vol.1, no.1, pp.1

  • Publication Type: Conference Paper / Summary Text
  • Volume: 1
  • City: Pula
  • Country: Croatia
  • Page Numbers: pp.1
  • Kocaeli University Affiliated: Yes


The carrier status and possible elevated resistance against the crayfish plaque (Aphanomyces astaci) of signal crayfish has been speculated for several decades. We studied the responses of two signal crayfish (Pacifastacus leniusculus) populations against the virulent crayfish plague infections under laboratory conditions. The tested populations were Leppävirta wild population and Raukola farmed population. The Leppävirta population

is from unknown origin of illegally stocking and the Raukola farmed crayfish are mixed wild signal crayfish originating from several southern Finland populations. Both test groups were infected with two A. astaci isolates and the inoculation dose was 10.000 spores mL-1. The isolates were PsI-genotype for Lake Puujärvi epidemic (year 1996) and As-genotype from Lake Kivesjärvi (year 2006?) epidemic in Finland. The test-population structure and morphological differences were measured according Miller’s formula. The crayfish were sampled prior to the experimental inoculation to evaluate the present carries status of each crayfish individual. The mortality, molting, feeding activity and behavior of the crayfish were followed during the experiment. We observed increased mortality of the infected groups, related to the molting in some cases, and delayed molting. The impacts of the intense crayfish plague infection on signal crayfish were clear and the studied populations showed differences in their reactions, maybe due to being in different physiological condition. The results show that external infection of both crayfish plague genotypes affects signal crayfish and causes losses among signal crayfish populations. Keywords: PsI and As-genotypes, mortality, molt, alien crayfish