Wels Catfish Introduced in 1974 Now Threaten Spain's Ebro River Ecosystem

A single introduction of Wels catfish into Spain's Ebro River by German biologist Roland Lorkowsky in 1974 has led to a major ecological crisis decades later. The species has established itself as a dominant predator in the river, putting native wildlife under serious threat. Their large size and aggressive feeding habits make population control extremely difficult for conservationists. Climate change is expected to further enable the species to spread across European waterways. Experts now consider the complete eradication of Wels catfish from the region to be virtually impossible.