Policy brief: Round goby – a threat or a new resource?

Originating from the Ponto-Caspian region, the invasive round goby has since 1990 spread in the Baltic Sea region, now with established populations throughout the area. The fish is a strong competitor for food, shelter and nesting sites, and has a high tolerance towards a broad range of temperatures and salinities. In many places, it exerts negative effects on the local fish fauna and benthic community, and its presence may compromise descriptors of Good Environmental Status under the Marine Strategy Framework Directive. Furthermore, Marine protected areas, constructed to protect valuable and threatened species or habitats, may be compromised by its presence. Notably however, round goby is also an emerging prey for larger fish, marine mammals and birds, thus providing positive effects to the invaded ecosystems. In some areas, it also supports fisheries, adding positively to society.