Indications of competition between non-indigenous round goby and native flounder in the Baltic Sea

Abstract

The Ponto-Caspian round goby (Neogobius melanostomus) was introduced to the Gulf of Gdansk, southern Baltic Sea, in the late 1980s, and it has now become the dominant demersal fish species in shallow water. This study aimed to assess diet preferences and the degree of diet overlap between the round goby and the native flounder (Platichthys flesus). Results from time-series of stomach contents and stable isotope analyses of wild-caught fish, together with prey preference experiments carried out in the laboratory, showed that the two species consumed similar species and sizes of prey. The similarities in diet suggest potential for food competition. Catch data showed both reverse depth distributions of round goby and flounder when round gobies were abundant and that the abundances of the two species were negatively correlated. The diet overlap between small flounders and round gobies was greatest when goby abundance was least, suggesting that abundance of round gobies may restrict flounder habitat utilization and, therefore, also food availability to the latter. Therefore, round gobies may have a negative influence on the commercially important flounder.

Keywords

diet overlap; diet preference; invasive species; ontogenetic diet shifts; stable isotopes

Published in

ICES Journal of Marine Science
2007, volume: 64, number: 3, pages: 479-486
Publisher: OXFORD UNIV PRESS

SLU Authors

• Appelberg, Magnus

  • Swedish Board of Fisheries

UKÄ Subject classification

Ecology

Publication identifier

• DOI: https://doi.org/10.1093/icesjms/fsl049

Permanent link to this page (URI)

https://res.slu.se/id/publ/42006