Round Goby Research Articles

Dietary partitioning of six co‐occurring Ponto‐Caspian gobies in the Dnieper River basin

AbstractThe diets and resource partitioning of six co‐occurring gobiids (Caucasian dwarf goby Knipowitschia caucasica; monkey goby, Neogobius fluviatilis; racer goby, Babka gymnotrachelus; round goby, Neogobius melanostomus; bighead goby, Ponticola kessleri; and western tubenose goby, Proterorhinus semilunaris) have been investigated in freshwater of the Dnieper River basin. The studied gobies were characterised by relatively similar generalised feeding strategies with the dominance of chironomid larvae in their diets, except Caucasian dwarf goby, the diet of which was dominated by copepods and cladocerans. The ontogenetic diet shift was clearly observed in all studied gobiids, except Caucasian dwarf gobies, adults of which had almost the same food spectrum as their juveniles. The highest diet overlaps were observed between monkey and racer gobies, and between monkey and round gobies. The lowest values of the diet overlap indices were recorded between Caucasian dwarf and round gobies, and between Caucasian dwarf and bighead gobies. Each studied goby species can be characterised by a unique set of features resulting in dietary partitioning such as consuming prey organisms inhabiting different microhabitats, different sizes, different spawning periods and ontogenetic diet shifts.

Round Goby Captured in a North American Estuary: Status and Implications in the Hudson River

Abstract Round Goby Neogobius melanostomus, a nonnative fish species to North America, has been rapidly expanding through the connected waterways of the Laurentian Great Lakes. Herein, we document the eastward and southern expansion of Round Goby into the Hudson River, New York, an iconic coastal estuary that drains to Long Island Sound and the Atlantic seaboard. In summer and early fall 2021, routine fish monitoring conducted by the New York State Department of Environmental Conservation documented a population of Round Goby in the tidal portion of the Hudson River. Over the course of monitoring in 2021, personnel collected 112 Round Goby between Albany, New York, and Poughkeepsie, New York, with the southernmost collection occurring approximately 140 km downstream of invasion front as reported in 2020 within the New York State Canal System. Although Round Goby previously colonized large rivers and streams in the Great Lakes watershed, there is little information about the invasion success and ecological impacts of Round Goby in estuarine environments in North America. We discuss the distribution and biological characteristics of the Hudson River Round Goby population as well as the potential ecological implications and areas of future research and monitoring for this range expansion.

Round Goby (Neogobius melanostomus) impacts on benthic fish communities in two tributaries of the Great Lakes

Numerous fish species in the Laurentian Great Lakes have been negatively impacted by the establishment of the invasive Round Goby (Neogobius melanostomus). However, limited understanding exists as to how Round Goby has impacted small-bodied native benthic fishes after its secondary invasion into tributaries of the Laurentian Great Lakes. To investigate Round Goby impacts on darter species (family Percidae) in tributary ecosystems, catch per unit area (CPUA) of native and non-native fishes from two riverine ecosystems in Southwestern Ontario (Ausable River, Big Otter Creek) were analyzed. Spatial analyses indicated Round Goby CPUA was highest proximate to the Great Lakes, with a sharp decline in CPUA at sites upstream from each lake (Round Goby CPUA approached zero after 18 and 14 km in the Ausable River and Big Otter Creek, respectively). There was some evidence of a negative relationship between the CPUA of Round Goby and several darter species along the tributary gradients, with moderately negative co-occurrence between Round Goby and Rainbow Darter in the Ausable River and Johnny Darter and Percidae species overall in Big Otter Creek. However, overwhelming evidence of negative associations between Round Goby and all darter species was not found. The negative relationship between the CPUA of Round Goby and some darter species was observed over similar time periods since establishment but greater spatial scales than in previous studies, and therefore has important implications for understanding the ecological impacts of Round Goby in tributary ecosystems.

Novel Fish Predator Causes Sustained Changes in Its Prey Populations

Ecosystems are simultaneously regulated by bottom-up (resources) and top-down forces (predators). However, because predator-prey interactions operate on spatial scales beyond the reach of manipulative experimentation, the actual roles of predators remain poorly understood. In ecosystems where predators are naturally absent, biological invasions provide a unique experiment to shed light on the large-scale and long-term effects of predators in the recipient ecosystem. We combined data from long-term benthic monitoring, environmental conditions, and a census of round goby population to identify changes in the dominant benthic bivalve population (Mytilus trossulus and Macoma balthica) following round goby (Neogobius melanostomus) invasion. This study demonstrates a substantial change in the food web, with earlier primarily bottom-up regulated communities facing strong top-down control effects. The introduction of a novel predator to a species-poor ecosystem substantially reduced dominant invertebrate populations in a large part of the study area, sometimes with a time lag of 1−3 years. In general, the effects were less in high productivity areas. In some cases, community recovery was observed but rarely to pre-invasion levels, raising the question of the ability of bivalve communities to act as a natural filter. This study demonstrates long-term trends in benthic communities and by excluding possible effects due to the changing environment provides more evidence that invasive species transform coastal ecosystems over time and space.

Different land uses influenced on characteristics and distribution of microplastics in Qarasu Basin Rivers, Gorgan Bay, Caspian Sea.

Concerns about the negative effects of microplastics (MPs) on human health have led to increasing attention to the occurrence of MPs in the aquatic environment. Recent studies have focus on the spatio-temporal distribution of MPs in rivers for residential and agricultural areas. Qarasu River Basin, watershed to Gorgan Bay, is the site of many permanent rivers and the levels of MP pollution in those rivers are unknown. This research was conducted in three different types of land use: forest, residential, and agricultural along 8 different rivers. A total of 9 fish species were identified and the presence of MPs in 87% of fish was confirmed. The prevalence of MP among species was Liza sp. > Carassius gibelio > Gambusia holbrooki > Rutilus rutilus > Neogobius melanostomus > Cyprinus carpio = Vimba vimba > Rutilus frisii > Barbus sp. The highest frequency of MPs was observed in Qarasu River (1880 ± 251 n/kg) and Mohammadabad River (184 ± 1340 n/kg) in agricultural land use, and the lowest frequency was related to Baghu and Ziarat Rivers with 660 ± 77 and 600 ± 91 n/kg found in forest land use respectively. The highest type, color, and size of MP sediments were fragment, black, and 1-2mm, respectively. The highest type, color, and size of MP in fishes were fiber, black, and 0.5-0.1mm respectively. Overall according to the source tracing result, agricultural land use was the main source of MP pollution of Gorgan Bay. The Bay is strongly affected by the incoming rivers, the Qarasu River Basin as the most important river supplying water.

Identifying high-risk areas for introduction of new alien species: the case of the invasive round goby, a door-knocker for Norway

AbstractIdentifying new areas of colonisation by alien species is important for early detection and management. Door-knocker species pose problems for traditional predictive models because of lacking presence–absence data, but habitat suitability modelling might overcome this. We here identify the most likely areas for introduction and first establishment of the invasive round goby Neogobius melanostomus to Norway, where it has not yet been registered. We implemented knowledge on dispersal pathways and the species’ biology in a simplified suitability model based on spatial data representing the most relevant environmental variables: distance to international harbours in Norway, distance to the closest population in neighbouring country, salinity, wave exposure, depth and water temperature. The results suggest that there are many potential localities for introduction and first establishment and reveal several hotspots of such areas, especially in less-exposed coastal brackish areas of southern Norway. Especially the region around the Oslo Fjord stands out as being associated with higher risk. Our results could guide future monitoring programmes and increase the chance of early detection of this potential new invader. The study illustrates how spatial analyses can be used to identify the most likely areas for future invasion by an aquatic door-knocker species despite lacking presence–absence data.

Comparative study on the oxidative stress of commercially important fish species from localities with different ecological conditions along the Bulgarian Black Sea coast

The aim of the present study was to perform a pilot assessment and analysis of the oxidative stress (OS) level in four commercially important fish species (round goby, red mullet, sprat and horse mackerel) from different localities of the Bulgarian Black Sea coast. The fish were sampled during trawl selectivity experiments. The OS level in the fish was assessed by measuring lipid peroxidation (LPO), glutathione concentration (GSH), activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), as well as acetylcholine esterase (AChE) in gills and liver. Round goby and red mullet caught in the Nessebar Bay showed clear signs of OS with the highest levels of LPO and GST activities, accompanied by the lowest AChE activities in both liver and gills. On the contrary, round goby caught near Maslen Nos (a region with good ecological conditions) were least affected by OS with low LPO and high GSH concentrations and SOD activity. There were no significant differences in the OS bioindicators of horse mackerel from the different localities. Sprat caught in Nessebar Bay, compared to those caught from the other localities, showed presence of OS indicated by lower GSH levels and relatively higher CAT, GPx and GST activities, accompanied by low AChE activity in gills. It can be concluded that round goby and red mullet were more vulnerable to OS induced by marine environmental factors than the horse mackerel and sprat. However, their antioxidant defense system allows them to tolerate and adapt to the environment of their habitats. Further studies are needed for the assessment of OS in important fish species in the Bulgarian part of the Black Sea.

Rapid response of the nearshore round goby population to temperature declines associated with upwelling events in Lake Ontario

Upwellings occur in all the Great Lakes in response to prolonged wind events. Several studies have modeled or measured changes in abiotic conditions associated with upwellings, but few direct observations of fish responses have been documented. Video-capture techniques were used in conjunction with moored temperature loggers to link the disappearance of benthic round gobies to temperature declines during upwelling events along the southern Lake Ontario nearshore in summer of 2019. Benthic water temperatures declined by as much as 18 °C within 18 h over as many as nine events. Round goby density estimates were as high as 50/m2 prior to upwellings, but declined to as low as 0/m2 during the events. Using just nine observation dates, ARMA trend analysis suggested a relationship between benthic temperature and round goby abundance (AIC = 78.7, t = 2.21, P = 0.063). Although the actual response of gobies to rapidly declining temperatures was unknown, this population was unobservable in our sample area during upwellings, yet returned to pre-upwelling densities within days. Understanding the magnitude and frequency of fish responses to these events can improve our understanding of the potential for this non-native benthic fish to affect the nearshore environment.

Trophic niche overlap between non-indigenous round goby, Neogobius melanostomus, and native fishes in tributaries of the lower Danube River (Bulgaria)

Abstract The recent expansion of the round goby (Neogobius melanostomus) in tributaries of the lower Danube (Bulgaria) prompted assessing potential negative effects on local fish fauna such as competition for food resources. Diet overlap between the round goby and native fishes was analyzed using samples of fishes and macroinvertebrates collected monthly for a one-year period. Significant dietary overlap between N. melanostomus and Barbus petenyi, Perca fluviatilis, Gobio gobio, Vimba vimba, and Neogobius fluviatilis was observed. Dietary overlap in the Iskar River was found to be considerable mainly in the spring months. Conversely, overlap in the Vit River was observed during summer and late fall. The main reason for the overlap noted was the preference for Chironomidae and Hydropsychidae larvae and Gammaridae. The results suggest that there is potential for competition between the round goby and native fish species inhabiting the tributaries of the Danube. Potentially harmful effects on rare, protected fish species in the area are discussed.

Two decades since first invasion: Revisiting round goby impacts on nearshore aquatic communities in the Upper St. Lawrence River

Time Since Invasion (TSI) at invaded sites is an important factor that can moderate invasive species abundances and their ecological impacts on resident communities, and yet it remains rarely addressed by invasion studies. We revisit the ecological impacts of round goby invasion in the Upper St. Lawrence River (Canada) on macroinvertebrate and fish communities, by taking into consideration the effects of TSI since initial invasion 20 years ago. Our objectives were to: 1) test the effect of TSI and invasion status on round goby abundance, and 2) investigate the effects of TSI, invasion status, and round goby abundance on macroinvertebrate and fish communities. Round goby abundance displayed a strong positive relationship with TSI. Environmental conditions, especially substrate and water conductivity were found to reduce round goby TSI and characterize uninvaded sites and >12 years TSI sites. However, we detected first potential signals of a reduction in round goby abundance at sites with TSI of 17–19 years compared with sites having 13–16 years TSI which had similar environmental conditions. Nonetheless, round gobies continued to have enduring impacts on total macroinvertebrate diversity, even at sites with TSI of 17–19 years, likely as a result of ongoing predation. This observation was supported by a negative association of round goby TSI on the abundance of dominant macroinvertebrate taxa at sampling sites in the Upper St Lawrence River, as well as dietary stomach content data. The fish community was less sensitive to round goby TSI than macroinvertebrate communities.

First documentation of spawning by deepwater sculpins in the Great Lakes and potential impacts of round gobies

Deepwater sculpins Myoxocephalus thompsonii, formerly fourhorn sculpin M. quadricornis (marine form), inhabit all five Great Lakes. Deepwater sculpin is prey for lake trout Salvelinus namaycush and feeds on benthos. Populations have been declining with possible reasons being oligotrophication, quagga mussels (Dreissena bugensis), predation, and impacts of round goby Neogobius melanostomus competition or predation on eggs. Deepwater sculpins are thought to spawn during winter based on gravid females and appearance of larval fish in spring, but a male guarding a nest has not been documented. We used remotely operated vehicle technology during December 2015, March 2017, and March 2021 in 70–191 m in Grand Traverse Bay, Lake Michigan to identify the distribution of deepwater sculpins, round gobies, and nests with a guarding male. Round gobies were much more abundant (observations/hr = 139) in water < 125 m than were deepwater sculpins (11/hr), while in water > 166 m, deepwater sculpins were much more common (39/hr) than at shallow sites. At deep sites, round gobies were more abundant (51/hr) than deepwater sculpins (39/hr). On 16 March 2021 in 190 m of 1.9 C surface water we discovered several presumptive, unoccupied nests, but one nest in a depression next to a branch contained a deepwater sculpin and a clump of eggs. This is first evidence of where and how deepwater sculpins spawn. We also documented round gobies in the same area with one within 2 m of the nest, creating the possibility for consumption of eggs potentially affecting their long-term survival.

Response of Long-Tailed Duck (Clangula hyemalis) to the Change in the Main Prey Availability in Its Baltic Wintering Ground.

Simple SummaryExtreme change in the benthic macrofauna community after invasion of the bottom fish round goby (Neogobius melanostomus) in the eastern Baltic Sea, challenged the declining long-tailed duck (Clangula hyemalis) population at the wintering ground. The aim of this study was to assess the change in the diet of the long-tailed duck in two different seabed types: highly impacted hard-bottom and adjacent pristine soft-bottom habitats. The results showed a significant change in the diet in hard-bottom habitats, while the diet in soft-bottom habitats remained similar over time. At the same time, the body condition did not differ over time or between habitats, confirming the high foraging flexibility and the quick species response to the extreme changes in prey composition and availability.The long-tailed duck (Clangula hyemalis) is a vulnerable and declining species wintering in the Baltic Sea. The introduction of the invasive fish, the round goby (Neogobius melanostomus), dramatically impacted the benthic macrofauna in hard-bottom habitats, while no significant changes occurred in soft-bottom benthic macrofauna. Therefore, we aimed to assess the extent to which the diet of long-tailed ducks changed in two different bottom types. We analysed the stomach content of 251 long-tailed ducks bycaught in gillnets from 2016 to 2020 in hard- and soft-bottom habitats and compared these results with those published by Žydelis and Ruškyte (2005). The results show that the long-tailed duck experienced a change in diet in hard-bottom habitats, shifting from the blue mussel to Hediste diversicolor, barnacles, and fish. In soft-bottom habitats, their diet remained similar over time and was based on H. diversicolor, a few bivalve species, and Saduria entomon. There was no evidence of significant differences in diet between sex or age. Despite the abovementioned changes in diet, the average body condition of the species did not change over time or between habitats. This confirms that long-tailed ducks have high feeding flexibility and quick species response to changes in prey availability, as they are capable of shifting their diet to new prey.

Morphological Differentiation of the Round Goby Neogobius melanostomus (Pallas, 1814) at the Northeastern Border of Its Invasive Distribution Range

Morphological Differentiation of the Round Goby Neogobius melanostomus (Pallas, 1814) at the Northeastern Border of Its Invasive Distribution Range

A Comparative Analysis of Biochemical Parameters in the Liver of Round Goby Neogobius melanostomus (Pallas, 1814) from Two Regions of the Taganrog Bay (Sea of Azov)

A Comparative Analysis of Biochemical Parameters in the Liver of Round Goby Neogobius melanostomus (Pallas, 1814) from Two Regions of the Taganrog Bay (Sea of Azov)

Application of biochemical and morphophysiological parameters of round goby Neogobius melanostomus (Pallas, 1814) for assessment of marine ecological state.

The ecological state assessment of the two areas in the Sea of Azov (Temryuk and Yasensky Bays) was carried out using morphophysiological (hepatosomatic and gonadosomatic indices) and biochemical parameters (activity of antioxidant enzymes (superoxide dismutase, catalase), aminotransferases, cholinesterase, level of oxidized proteins, and lipid peroxidation), as well as the toxicological parameters in the liver of round goby Neogobius melanostomus. The results of the biochemical analysis allowed to establish a shift of the prooxidant-antioxidant reactions towards the processes of protein oxidation, also an increase of aminotransferase activities in the fish liver from Temryuk Bay compared to similar indicators in fish from Yasensky Bay. At the same time, the average values of length and weight as well as the gonadosomatic index were found significantly lower, while the hepatosomatic index significantly higher in fish from Temryuk Bay as compared to similar indices of fish from Yasensky Bay. Analysis of the biochemical and morphophysiological parameters of round goby from the two locations demonstrates less favorable ecological state of the Temryuk Bay that fully agrees with the results of the elementary analysis in the fish liver. Studied parameters can be used in the ecological monitoring of the natural surroundings of this species and the areas beyond.

Monitoring of environmental DNA from nonindigenous species of algae, dinoflagellates and animals in the North East Atlantic

Monitoring the distribution of marine nonindigenous species is a challenging task. To support this monitoring, we developed and validated the specificity of 12 primer-probe assays for detection of environmental DNA (eDNA) from marine species, all nonindigenous to Europe. The species include sturgeons, a Pacific red algae, oyster thief, a freshwater hydroid from the Black Sea, Chinese mitten crab, Pacific oyster, warty comb jelly, sand gaper, round goby, pink salmon, rainbow trout and North American mud crab. We tested all assays in the laboratory, on DNA extracted from both the target and non-target species to ensure that they only amplified DNA from the intended species. Subsequently, all assays were used to analyse water samples collected at 16 different harbours across two different seasons during 2017. We also included six previously published assays targeting eDNA from goldfish, European carp, two species of dinoflagellates of the genera Karenia and Prorocentrum, two species of the heterokont flagellate genus Pseudochattonella. Conventional monitoring was carried out alongside eDNA sampling but with only one sampling event over the one year. Because eDNA was relatively fast and easy to collect compared to conventional sampling, we sampled eDNA twice during 2017, which showed seasonal changes in the distribution of nonindigenous species. Comparing eDNA levels with salinity gradients did not show any correlation. A significant correlation was observed between number of species detected with conventional monitoring methods and number of species found using eDNA at each location. This supports the use of eDNA for surveillance of the distribution of marine nonindigenous species, where the speed and relative easy sampling in the field combined with fast molecular analysis may provide advantages compared to conventional monitoring methods. Prior validation of assays increases taxonomic precision, and laboratorial setup facilitates analysis of multiple samples simultaneously. The specific eDNA assays presented here can be implemented directly in monitoring programmes across Europe and potentially worldwide to infer a more precise picture of the dynamics in the distribution of marine nonindigenous species.

Tracking the early stages of an invasion with biotelemetry: behaviour of round goby (Neogobius melanostomus) in Canada’s historic Rideau Canal

Tracking the early stages of an invasion with biotelemetry: behaviour of round goby (Neogobius melanostomus) in Canada’s historic Rideau Canal

Proximity to Riparian Wetlands Increases Mercury Burden in Fish in the Upper St. Lawrence River

Mercury deposited in the Upper St. Lawrence River watershed by atmospheric deposition accumulated in riparian wetlands and is at risk of remobilization due to water level fluctuations. To examine if riparian wetlands are a source of mercury to fish, 174 yellow perch (Perca flavescens) and 145 round gobies (Neogobius melanostomus) were collected in 2019 from eight wetland and seven non-wetland habitats throughout the Upper St. Lawrence River. Mercury levels were significantly (p &lt; 0.01) higher in fish collected from wetlands than those collected from non-wetland habitats for both yellow perch and round goby. Perch had mercury concentrations of 74.5 ± 35.4 ng/g dry wt in wetlands compared to 59.9 ± 23.0 ng/g dry wt in non-wetlands. Goby had mercury concentrations of 55.4 ± 13.8 ng/g dry wt in wetlands and non-wetland concentrations of 41.0 ± 14.0 ng/g dry wt. Riparian wetlands are areas of elevated mercury methylation and mobilization in the Upper St. Lawrence River and consequences to predators should be considered from the perspective of both wildlife preservation as well as fish consumption advisories for public health concerns.

Morphological differentiation of the round goby &lt;i&gt;Neogobius melanostomus&lt;/i&gt; (Pallas, 1814) by north-east border of the invasive distribution range

Morphological differentiation of the round goby &lt;i&gt;Neogobius melanostomus&lt;/i&gt; (Pallas, 1814) by north-east border of the invasive distribution range

Boldness and Physiological Variation in Round Goby Populations Along Their Baltic Sea Invasion Front

Boldness and Physiological Variation in Round Goby Populations Along Their Baltic Sea Invasion Front