Abstract

The white-clawed crayfish (Austropotamobius pallipes) is an endangered species in Switzerland. It is native to the cantons of Berne, Waadt and Wallis, where the American species Orconectes limosus also occurs. The first record of O. limosus is from 1979 in Lake Biel. Since then it expanded its range continuously, and early in 1998 it was found in the River Aare 90 km downstream of Lake Biel. Because of its resistance to the crayfish plague (Aphanomyces astaci) it is a potential threat to Austropotamobius pallipes. This paper assesses an actual or potential threat of O. limosus to A. pallipes. In summer and fall of 1997 a total of 63 streams were surveyed. O. limosus was found in 17 out of 43 streams draining either into Lake Biel or the River Aare. O. limosus was restricted to the immediate surroundings of the stream outlets. A. pallipes was found only in 5 out of 20 streams where the species had been recorded since 1990 by local authorities. No sites with both species were found.

Supplemental Documents

• There are no supplementary documents for this article

Cited By

Citations: