They have felt comfortable in Berlin for several years – now an American type of crab is spreading in southern Hesse and threatening other animals. “We see a strong spread along the entire Rhine,” said the state chairman of the Hessian nature conservation association, Gerhard Eppler. Residents like Frank Baumgart from Raunheim also noticed the reddish scissor bearers. Various media had previously reported.
“The little guys have already beheaded a few fish at a neighbor’s,” reported Baumgart. Almost three years ago he noticed the atypical guest in the pond for the first time. After a short time he disappeared again. “Several people came this year,” said the neighbor.
Not only fish owners see this as a problem, but also the Hessian nature conservation association. Because the species multiplies quickly – and thus spreads a disease: crayfish plague. “They are immune to it themselves, but our crabs die from it,” said Eppler. There is no health risk for humans. Specifically, the invasive species is American red swamp crayfish.
“Very voracious” omnivores
The conservationist first discovered the crabs in 2005 in the Rhine-Main area. They were brought to Germany, among other things, as fishing bait. “Now they attract attention, because after the constant rain they also walk across the country,” says Eppler. In addition, the American swamp crabs are omnivores and “very voracious,” the conservationist reported. “It doesn’t matter whether it’s aquatic plants, fish spawn, frog spawn – they eat everything that gets in their way.” And another problem: “Once these American crabs have conquered a body of water, you can’t get rid of them again.”
In August 2017, migratory swamp crayfish were sighted in the Tiergarten in Berlin, until then their occurrence had gone largely unnoticed for a long time. The roughly palm-sized animals (Procambarus clarkii) are actually found in the southern United States and northern Mexico.
