Predator and prey: the role of the round gobyNeogobius melanostomusin the western Baltic

Abstract

Different studies on the position of the non-indigenous species Neogobius melanostomus within the coastal food web of the Pomeranian Bay (western Baltic) were performed, resulting in a quantitative and qualitative species list of prey organisms found in the stomachs of the invader and an estimation concerning the importance of round goby as prey for different resident predators. It seems that the colonization process is not fully completed yet, but the results reveal that the species is already established in the food web 16 years after the first observation within the study area. The results show that N. melanostomus feed upon a wide range of different resident organisms. While a direct predation effect on native fish species appears rather unlikely, indirect effects such as competition cannot yet be excluded. In addition, our results reveal an ontogenetic diet shift and that the round goby itself already serves as an important prey for piscivorous fish and seabirds. Finally, we formulate different hypotheses based on our results which will require further research. ARTICLE HISTORY

Using acoustic telemetry and snorkel surveys to study diel activity and seasonal migration of round goby (Neogobius melanostomus) in an estuary of the Western Baltic Sea

“…Species that migrate from coastal areas often transport large amounts of energy and nutrients to deeper waters where predatory species feed on the migrants (Deegan, ; Möller, Pihl & Rosenberg, ). Since it is increasingly recognised that resident piscivores, such as turbot Scophthalmus maximus (L.), pikeperch Sander lucioperca (L.), perch Perca fluviatilis L. and cod Gadus morhua L. , feed on the round goby (Almqvist, Strandmark & Appelberg, ; Alstrup, Jensen, Christoffersen & Svendsen, ; Hempel, Neukamm & Thiel, ; Kornis et al., ; Oesterwind et al., ), it is likely that the seasonal migration performed by the round goby may provide a vector for food resources away from the coastal zone.…”

“…perch Perca fluviatilis L. and cod Gadus morhua L., feed on the round goby (Almqvist, Strandmark & Appelberg, 2010;Alstrup, Jensen, Christoffersen & Svendsen, 2017;Hempel, Neukamm & Thiel, 2016;Kornis et al, 2012;Oesterwind et al, 2017), it is likely that the seasonal migration performed by the round goby may provide a vector for food resources away from the coastal zone.…”

“…Numerous studies have reported negative ecosystem effects in the wake of the invasion of round goby (Balshine, Verma, Chant & Theysmeyer, 2005;Demchenko & Tkachenko, 2017;Karlson, Almqvist, Skora & Appelberg, 2007;Kornis et al, 2012;Lauer, Allen & McComish, 2004;Oesterwind et al, 2017;Sapota, 2004;Schrandt et al, 2016), yet few attempts have been made to mitigate the effects (Dorenbosch et al, 2017;Ojaveer et al, 2015). One potential approach to reduce round goby numbers and the ecological footprint could be to develop a targeted fishery for the species.…”

Habitat utilization and feeding ecology of small round goby in a shallow brackish lagoon

“…Although first records of this species at the German coast of the Baltic Sea date back to 1998 (Winkler 2006), in our study area, round gobies were first caught in 2011 (Paul Kotterba, personal observation). Thus, we are exploring the basic ecology of this invasive species in a region, which has been invaded rather recently but where round goby has already established a viable population, which is why information on its ecology, especially the consideration of several habitat types, is quite scarce (Oesterwind et al 2017;Wiegleb et al 2018). This study will therefore contribute to broadening the knowledge on round goby in its invaded range, which is needed to more reliably predict potential impacts on ecosystems.…”

“…Concurrently, round gobies have become established in local food webs, feeding on a wide range of native organisms and serving as prey for several predatory fish species (e.g. cod and perch) and birds, such as cormorants and herons (Johnson et al 2005;Almqvist et al 2010;Hempel et al 2016;Oesterwind et al 2017;Herlevi et al 2018). In their colonized range, round gobies can have severe impacts on the native fauna as they compete with native fish species for food resources and habitat, and prey on fish fry and juveniles (e.g.…”