engleski

The Influence Of Global Warming On The Interaction Between Freshwater Crayfish And Pathogen Aphanomyces astaci (Schikora, 1906), The Causative Agent Of Crayfish Plague

Crayfish are the keystone species of freshwater ecosystems. However, in recent decades populations of indigenous European crayfish species (ICS) significantly declines due to numerous anthropogenic impacts, which include the spread of non-indigenous crayfish species (NICS) and climate change. Moreover, populations decline is increased since the migration of ICS to more favorable places in freshwater ecosystems is limited. NICS are carriers of the crayfish plague disease, whose causative agent is the microorganism Aphanomyces astaci (Schikora, 1906) (Oomycetes). This pathogen is main reason of ICS declines and increasing of NICS. The aim of this study was to investigate if increasing of water temperature (caused by global worming) would have an impact on virulence of pathogen A. astaci and the physiological condition of two native species of crayfish: the narrow-clawed crayfish (Astacus leptodactylus Eschscholtz, 1823) and the stone crayfish (Austropotamobius torrentium (Schrank, 1803)). Since we used new noninvasive method of molecular detection of pathogen from the crayfish cuticle we could select non-infected individuals for our experiments, as well as to identify the cause of death of crayfish during the experiment. Th both species were infected with 500 A. astaci strain B (PsI genotype) zoospores / mL at two water temperatures: 18 ° C (control temperature) and 22 ° C (elevated temperature – simulation of global warming). The mortality rate of both species was monitored for four weeks. Results show the reduction of virulence of A. astaci pathogen on elevated water temperature (22 °C), but it is also caused higher mortality range for endangered native species A. torrentium. In conclusion, global worming might decrease virulence of A. astaci (strain B, PsI genotype) but it could affect fitness of native crayfish species such as A. torrentium. This is the first study which present connection between virulence of pathogen A. astaci and the water temperature.

global warming, native crayfish species, crayfish plague disease, noninvasive method for molecular detection of A. astaci

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