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

image of 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.



Round goby as an emerging prey item and potential new resource

In regions where round gobies have become abundant, they have become important prey items for piscivorous predators. They are e.g. the main prey for cod and perch in the Gulf of Gdansk and increasingly important prey for perch in Estonia. In Lithuania round gobies were found in the diet of most piscivorous fish species including turbot or even such species as Shorthorn sculpin, the same being the case in the Curonian Lagoon, where it is part of the diet of all top predators. Some piscivorous fish, such as sander, show higher length-at-age values after the invasion. Furthermore, the nutritional value of round goby, having a high protein content and a favorable fatty acid composition makes it a superior prey for growth of cod. Round gobies are also important prey for piscivorous birds, such as great cormorant and grey heron. Thus, it is clear that positive effects of round goby are also to be seen in the wake of its invasion.


This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error