Science – Exlach – An important stone crab colony throughout Germany – Bavaria

Axelach (dpa/lby) – Researchers have discovered an unusually large settlement of stone crabs in a small, unnamed stream near Axelach in the Riegen region of Lower Bavaria. The Bavarian State Office for the Environment (LfU) announced on Wednesday that the population is nationally important and deserves protection.

According to an LfU spokesperson, the stone lobster distribution center in Germany is located in Baden-Württemberg and Bavaria, in the catchment areas of the South Rhine and Western Danube. The population now found has one of the highest known animal densities in the entire Free State.

The animals colonized headwaters and ditches with good water quality in Bavaria. The main distribution areas are in the foothills of the Alps and in low mountain ranges. The spokesperson explained that as a result of invasive crayfish species such as the signal crayfish and crayfish plague – an infectious disease that is almost always fatal to native species – many populations are at great risk or have already been wiped out.

According to the Rijn District Office, researchers from the Aquatic Ecology Office have mapped crayfish at 157 sites in the Rijn and Freung Grafenau districts. Experts said that stone crabs were discovered in eleven places, non-local signal crabs in five places, and noble crabs in four places.

Of all places, 710 stone crabs were counted per 100 meters in an unnamed stream in the municipality of Axelach – according to experts, an unusually high number, at least in Germany. The large numbers of noble crayfish in the tributaries of the Gengartinger Bach in the Friung-Gräfenau region are said to be causing a sensation as well. They are at severe risk from migrating crayfish.

“The biggest problem facing native crayfish in general is the spread of the signal crayfish. It is a carrier of the crayfish plague, which usually leads to the extinction of entire populations of stone crayfish and noble crayfish,” said Martin Graf of Nature Conservation Regen. authority. “The signal crayfish, which comes from North America, is itself immune to the crayfish plague, but is able to transmit it. It is also defensive and aggressive, and its reproduction rate is also higher than that of the noble crayfish.”

© dpa-infocom, dpa:240228-99-156251/2