Signal crayfish Pacifastacus leniusculus is a freshwater crayfish deliberately introduced to Europe from North America during the 20th century. The signal crayfish turned out to be a chronic carrier of crayfish plague and a threat to several species of freshwater crayfish native to Europe. In 2016, it was one of the first species placed on the list of Invasive Alien Species of Union concern under the new EU Regulation on Invasive Alien Species. This listing implies that all member states must take action to eradicate or control the species, in particular prevent further spread. This year (2018) each member state has had two years to develop and adopt a national risk management programs for the signal crayfish. Based on interviews with regulators and crayfish experts in different member states, we will compare the risk management strategies taken by member states in which the signal crayfish. Where the species is widely spread today, the demand for eradication is replaced by cost effective measures to control and prevent further spread. We discuss the differences in the way this alternative is interpreted and see if they can be explained by differences in risk perception and values.