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Invasive crayfish and crayfish plague on the move: first detection of the plague agent Aphanomyces astaci in the Romanian Danube

Domenii publicaţii > Biologie + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: Pârvulescu L, Schrimpf A, Kozubíková E, Resino SC, Vrálstad T, Petrusek A, Schulz R.

Editorial: Diseases of Aquatic Organisms, 2012.

Rezumat:

Native European crayfish, such as Astacus leptodactylus, are threatened among other factors by the crayfish plague agent Aphanomyces astaci, dispersed by invasive North American crayfish. Two of these invaders, Pacifastacus leniusculus and Orconectes limosus, have extended their distribution in the River Danube catchment; the latter was detected for the first time in Romania in 2008. We monitored, at monthly intervals for over two years, occurrence of native A. leptodactylus and invasive O. limosus at six sites on the Romanian Danube. Furthermore, we checked for the invasive species in four of its tributaries. Between January 2009 and March 2011, the relative abundances of O. limosus steadily increased with time, while the native A. leptodactylus dramatically decreased in abundance. O. limosus expanded downstream at a rate of ca 15 km yr-1; in August 2011, it already occurred in the upper 105 km of the Romanian Danube. An agent-specific real-time PCR analyses demonstrated the presence of A. astaci DNA in at least 32% of the analysed invasive (n = 71) and 41% of the native (n = 49) crayfish coexisting in the Danube. Furthermore, A. astaci was also detected in A. leptodactylus captured about 70 km downstream of the O. limosus invasion front (at the time of sampling). Assuming a steady rate of expansion, O. limosus may invade the sensitive Danube delta area in the mid-2060s, even without involving long-distance dispersal. The crayfish plague agent, however, may reach the delta substantially earlier, through dispersal downstream among populations of native crayfish.

Cuvinte cheie: crayfish plague, Aphanomyces astaci, quantitative real-time PCR, molecular diagnostics, Danube, non-indigenous crayfish, Orconectes limosus, indigenous crayfish, Astacus leptodactylus

URL: http://dx.doi.org/10.3354/dao02432