Impacts of the Eurasian round goby (Neogobius melanostomus) on benthic communities in the upper St. Lawrence River

Abstract

An invasive benthivorous fish, the Eurasian round goby (Neogobius melanostomus) is abundant throughout the lower Great Lakes -St. Lawrence River system. We examined the round goby's potential to alter benthic communities on cobble substrates in the upper St. Lawrence River. During the summers of 2008 and 2009, macroinvertebrates and benthic algae were sampled across sites with varying goby densities. Archived data from various sites in 2004-2006 (prior to invasion) were available for comparison. Macroinvertebrate community composition varied significantly among samples grouped into categories based on goby density and time since invasion. Macroinvertebrate diversity and dominance by large-bodied taxa declined with increasing goby density. Surprisingly, dreissenid biomass did not vary consistently with goby density, in contrast to studies in the Great Lakes. The biomass of all non-dreissenid taxa was negatively correlated with increasing goby density across sites and over time at three of four sites. Negative effects were most pronounced on the biomass of gastropods. Benthic algal biomass increased with goby density across sites, suggesting a trophic cascade driven by the impacts of gobies on gastropods and other algivores. Our study highlights the potential ecosystem impacts of an expanding goby population in a large river.Résumé : Le poisson envahissant, consommateur de benthos, le gobie à taches noires d'Eurasie, Neogobius melanostomus, est abondant dans l'ensemble du système des Grands Lacs inférieurs et du Saint-Laurent. Nous étudions le potentiel qu'a le gobie à taches noires pour modifier les communautés benthiques sur les substrats pierreux dans la région amont du SaintLaurent. Durant les étés 2008 et 2009, nous avons échantillonné les macroinvertébrés et les algues benthiques dans un ensemble de sites présentant des densités diverses de gobies. Il existe des données en archives pour plusieurs sites en 2004-2006 (avant l'invasion) pour servir de comparaison. La composition des communautés d'invertébrés varie significativement dans les différents échantillons regroupés en catégories d'après la densité des gobies et le temps depuis l'invasion. La diversité des macroinvertébrés et la dominance des taxons de grande taille diminuent en fonction de l'augmentation de la densité des gobies. De manière inattendue, la biomasse des dreissénidés ne varie pas de manière cohérente en fonction de la densité des gobies, comme elle le fait dans les Grands Lacs selon certaines études. Dans trois de quatre sites, la biomasse de l'ensemble des taxons moins les dreissénidés est en corrélation négative avec l'accroissement des gobies dans les divers sites et les différentes périodes. Les effets négatifs les plus prononcés s'observent sur la biomasse des gastéropodes. La biomasse des algues benthiques augmente en fonction de la densité des gobies dans les différents sites, ce qui laisse croire à une cascade trophique causée par les impacts des gobies sur les gastéropodes et les autres consommateurs d'algues. Notre étude soulign...

Bigger Is Better: Characteristics of Round Gobies Forming an Invasion Front in the Danube River

“…The decreasing trend in CPUE and I EI in EPT by time, with highest values at the IF2010 clearly highlights the impact of round goby on native biodiversity, similar to the one described by Kipp and Ricciardi (2012) [25] for North American rivers. Underlining the extraordinary preference of round goby for these native taxa, the I FI (EPT) by far exceeded the I EI (EPT) in all round goby populations (Table 4).…”

“…Its rapid spread and the high potential to cause ecological regime-shifts (e.g., [22]–[25]) have mobilized substantial scientific interest in this species as a model to study invasion biology processes worldwide (reviewed in Kornis et al, 2012 [26]). In the last two decades, an increasing number of rapid range expansions of N. melanostomus have been reported from the Laurentian Great Lakes watershed [21], [27]–[31], from almost the entire Baltic Sea region [32]–[34] and from many other large European waterbodies, including the Danube River [13], [35], [36] and the River Rhine [37].…”

Diet shift response in round goby,Neogobius melanostomus, based on size, sex, depth, and habitat in the western basin of Lake Erie

“…Further study of the round goby diet is needed to establish the invasion effects on the local macroinvertebrate and algal communities. Kipp and Ricciardi () reported not only a decrease in macroinvertebrate density with goby invasion, but also an increase in algal blooms due to the impact of goby individuals on native algivores, making it all the more important to study the extent to which they are feeding on this type of prey. To fully understand any lifetime changes in round goby diet and gain information for management to control the spread of this invasive species, the choice of round goby prey must be better understood.…”

Harmful Algal Blooms

“…Early efforts to reduce these blooms were successfully engineered via nutrient management; remedial efforts were followed by a dramatic decrease in these benthic blooms through the 1980s and early 1990s (Higgins et al, 2008). Other top-down factors may alter conditions, such as predation by invasive gobies on invertebrate grazers, which may relax their grazing pressure on Cladophora (Kip and Ricciardi, 2012). It is now evident that several of the key factors controlling the biomass of this species in these lakes, notably light penetration, nutrient recycling, and substrate availability, are strongly influenced by the filtering activity and growth of the invasive dreissenid mussels (Auer et al, 2010;Higgins and Vander Zanden, 2010;Higgins et al, 2012).…”