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

Abstract

Karlson, A. M. L., Almqvist, G., Skóra, K. E., and Appelberg, M. 2007. Indications of competition between non-indigenous round goby and native flounder in the Baltic Sea. – ICES Journal of Marine Science, 64: 479–486. The Ponto-Caspian round goby (Neogobius melanostomus) was introduced to the Gulf of Gdańsk, 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.

Occurrence of cyanobacteria and cyanotoxin in the Southern Baltic Proper. Filamentous cyanobacteria versus single-celled picocyanobacteria

“…The observed difference probably results from the food and habitat preferences of the two organisms. The round gobies prefer more shallow waters and blue mussels constitute their primary food component (Sapota, 2004;Karlson et al, 2007). The flounders migrate between the coast and off-shore waters and Macoma baltica constitute a more important element of their diet.…”

“…The concentrations of NOD in mussels at two different stages of their development were compared. The concentration of NOD was also measured in two species of bottom dwelling fish, flounder and round goby, characterized by different food and habitat preferences (Karlson et al, 2007). In round goby, the accumulation of nodularin has been analyzed in this work for the first time.…”

Predicting trophic guild and diet overlap from functional traits: statistics, opportunities and limitations for marine ecology

“…In addition, overlap in diet composition and resource partitioning between species is a key element of interspecific competition that can determine stable coexistence (Sala & Ballesteros 1997, Colloca et al 2010. Determining the level of diet overlap among species is, therefore, also a major tool in predicting extirpations of species as a result of competitive interactions with invasive species (Karlson et al 2007, Glen & Dickman 2008, Arismendi et al 2009, Gregory & Macdonald 2009, Zeug et al 2009). …”

Different life-histories of native and invasiveNeogobius melanostomusand the possible role of phenotypic plasticity in the species’ invasion success

“…Their impacts vary from local environmental disturbances (competition for food and habitat, predation, introduction of parasites, replacing native species), over the extinction of endemic species, to large economic losses (aquaculture) and serious threats to human health, such as allergies, introduction of parasites and disease (Janssen and Jude, 2001;Lauer et al, 2004;Hogan et al, 2007;Karlson et al, 2007;Kornis et al, 2012). One of the most successful invasive fish species with negative impacts is round goby Neogobius melanostomus (Pallas 1814) that has spread from its original Ponto-Caspian area to west and central Europe and even to North America (Jude et al, 1992;Skóra and Stolarski, 1993;Copp et al, 2005;Verreycken et al, 2011).…”