Zander was introduced in the late 1990s. crayfish plague caused a population of European crayfish to disappear in 1984, subsequently replaced by signal crayfish introduced throughout the 1990s.
The Zander species was introduced in the late 1990s. The introduction of non-native crayfish led to a significant decline in the European crayfish population due to disease, starting with the plague in 1984, and subsequently replaced by signal crayfish that were widely distributed throughout the decade.