scholarly journals 2D vs. 3D Numerical Approaches for Fish Habitat Evaluation of a Large River — Is 2D Modeling Sufficient?

2021 ◽  
Author(s):  
Vivien Füstös ◽  
Tibor Erős ◽  
János Józsa
Keyword(s):  
Habitat Suitability ◽  
Fish Habitat ◽  
Round Goby ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Large River ◽  
Neogobius Melanostomus ◽  
Danube River ◽  
Habitat Evaluation ◽  
Hydrodynamical Simulations

Computational Fluid Dynamics is an effective tool for assessing non-present conditions, thus also in habitat evaluation within ecohydraulics. Deciding whether to apply a one-, two- or three-dimensional numerical approach, is an optimization that needs to be performed by every task, given the capability and the demands of specific approaches. In this paper we compare the utility of two-dimensional (2D) versus three-dimensional (3D) hydrodynamical simulations for ecohydraulic purposes. The basis of the comparation were 1) three simulated abiotic variables: water depth, depth averaged flow velocity and bed material composition, and 2) an overall performance in a meso-scale fish habitat evaluation, based on the simulated three variables. The biotic parameters for the models were the habitat suitability curves of three fish species, the Danube streber (Zingel streber), the round goby (Neogobius melanostomus) and the white bream (Blicca bjoerkna). We found that in terms of ecohydraulic utilization, the 2D approach performed sufficiently to simulate the hydrodynamics of a large river. The errors originating from the 3D-2D simplification yielded negligible differences in habitat evaluation, and the agreement in the habitat suitability indices calculated from the simulated metrics was satisfactory. Henceforth, the theory was turned into an application as we performed habitat mapping on a 100 km long, Hungarian reach of the Danube River, with the abiotic parameters resulting from a 2D hydrodynamical simulation. The possibility of simplifying the approach from 3D to 2D provides a cost-efficient numerical tool at larger scales for ecohydraulic studies, and especially for evaluating habitat suitability of riverine fish.

scholarly journals Summer microhabitat use and overlap by the invasive Round Goby (Neogobius melanostomus) and native darters in the Trent River (Ontario, Canada)

2019 ◽  
pp. 23
Author(s):  
Scott M. Reid
Keyword(s):  
Habitat Suitability ◽  
Native Species ◽  
Round Goby ◽  
High Water ◽  
Neogobius Melanostomus ◽  
Microhabitat Use ◽  
Intermediate Water ◽  
Habitat Differences ◽  
Species Declines ◽  
Water Depths

Understanding the impacts of the invasive Round Goby (Neogobius melanostomus) is important for North American native fish conservation. One proposed mechanism for native species declines is competition for habitat. In this study, summer habitat use by Round Goby and Channel Darter (Percina copelandi) and Logperch (P. caprodes) was studied in the Trent River (Canada). Spot-electrofishing and systematic habitat sampling were used to measure habitat availability and use. Suitability for all species varied across the range of habitat conditions. At Glen Ross, habitat suitability for Channel Darter and Round Goby was highest at intermediate water depths (0.2–0.6 m), lowest at high water velocities (> 1.0 ms−1) and increased with greater amounts of gravel and cobble. There were no significance habitat differences between capture locations of the two species. At Meyer's Reach, Logperch and Round Goby habitat suitability was highest at intermediate water depths (0.4–0.6 m) and where gravel and cobble were abundant. The relationship between suitability and water velocity differed between species, with moderate velocities less suitable for Round Goby. The amount of boulder and bedrock at capture locations of each species differed. Results indicate that competition for habitat with Round Goby will vary among darter species.

Parasites of Apollonia melanostoma (Pallas 1814) and Neogobius kessleri (Guenther 1861) (Osteichthyes, Gobiidae) from the Danube River in Austria

2009 ◽  
Vol 84 (1) ◽  
pp. 87-92 ◽  
Author(s):  
J.M. Mühlegger ◽  
F. Jirsa ◽  
R. Konecny ◽  
C. Frank
Keyword(s):  
Round Goby ◽  
Body Cavity ◽  
Parasite Fauna ◽  
Neogobius Melanostomus ◽  
The Body ◽  
Danube River ◽  
The Danube River ◽  
Acanthocephalus Lucii ◽  
Apollonia Melanostoma ◽  
Low Prevalence

AbstractTwo invasive fish species, the round goby Apollonia melanostoma syn. Neogobius melanostomus (Pallas 1814) and the bighead goby Neogobius kessleri (Günther, 1861), have established a firm population in Austrian waters during the past 15 years. As there have been no records of the parasite fauna from these populations, a total of 79 specimens of A. melanostoma and 12 specimens of N. kessleri were examined for parasites between May and October 2007 from three different sampling sites from the Danube River in Austria. In total 12 parasite taxa were recovered. The protozoans Trichodina sp. and Ichthyophthirius multifiliis from the gills and skin; two crustacean species, Paraergasilus brevidigitus and Ergasilus sieboldi, from the gills; and the two monogeneans Gyrodactylus sp. and Dactylogyrus sp., from the skin and gills respectively, all occurred at low prevalence and intensities. Furthermore, cystacanths of the acanthocephalan Acanthocephalus lucii were found in the body cavity. Metacercariae of the digeneans Diplostomum sp. and Tylodelphys clavata were found in the lens of the eye and the vitreous humour, respectively. Adults of two digeneans, Nicolla skrjabini and Bunodera nodulosa, were found in the intestine. In addition, during this survey metacercariae of the Holarctic digenean Bucephalus polymorphus, encysted in the skin and fins, with prevalence up to 78%, were recorded for the first time in Austria.

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

2012 ◽  
Vol 69 (3) ◽  
pp. 469-486 ◽  
Author(s):  
Rebekah Kipp ◽  
Anthony Ricciardi
Keyword(s):  
Great Lakes ◽  
Benthic Communities ◽  
Round Goby ◽  
River System ◽  
Benthic Algae ◽  
Large River ◽  
Neogobius Melanostomus ◽  
Benthivorous Fish ◽  
Ecosystem Impacts ◽  
St Lawrence River

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.

scholarly journals Abundance, distribution, and habitat use of fishes in a large river (Danube, Austria): mobile, horizontal hydroacoustic surveys vs. a standard fishing method

2020 ◽  
Vol 77 (5) ◽  
pp. 1966-1978
Author(s):  
Philip Kerschbaumer ◽  
Michael Tritthart ◽  
Hubert Keckeis
Keyword(s):  
Habitat Use ◽  
Three Dimensional ◽  
Large River ◽  
Fish Abundance ◽  
Danube River ◽  
Fish Length ◽  
Specific Information ◽  
Catch Per Unit Effort ◽  
Temporal And Spatial Distribution ◽  
Imaging Sonar

Abstract We tested a novel approach for fish abundance and size estimates along a 3.6-km reach in the main stem of a free-flowing section of the Danube River east of Vienna. We deployed an adaptive resolution imaging sonar (ARIS) with horizontal beam orientation from a moving boat in order to assess spatial and temporal fish abundance distributions in different mesohabitats. To validate the results obtained from imaging sonar, hydroacoustic abundance and fish length estimates were compared with those received from boat electrofishing surveys conducted at the same time and place. Furthermore, fish occurrence was related to hydraulic conditions based on a three-dimensional hydrodynamic model in order to reveal patterns of habitat use. Hydroacoustic abundance expressed as catch per unit effort estimates deviated significantly from fish abundances assessed by boat electrofishing, but when comparing relative abundances both methods yielded a similar spatial and temporal pattern. Total fish length estimates obtained from the two methods did not differ significantly. The mobile application of the non-invasive ARIS technology offers the opportunity to quickly gain detailed information on fish abundance and position of individuals. This yields more specific information on temporal and spatial distribution patterns, habitat use and fish size distributions in large rivers.

scholarly journals Cryptic alternative male mating strategies in invasive alien round goby (Neogobius melanostomus) of the upper Danube River

2020 ◽  
Author(s):  
Alexander F. Cerwenka ◽  
Joerg Brandner ◽  
Juergen Geist ◽  
Ulrich K. Schliewen
Keyword(s):  
Life History ◽  
Sexual Maturity ◽  
Round Goby ◽  
Trophic Niche ◽  
Mating Strategies ◽  
Neogobius Melanostomus ◽  
Danube River ◽  
Life History Strategies ◽  
Male Mating ◽  
Male Mating Strategies

Abstract Male alternative mating strategies are a widespread life history choice, yet they have hardly been assessed in the context of fish invasions. As established proxies for alternative life-history strategies, body length and sexual maturity of Ponto–Caspian round goby (Neogobius melanostomus) from the recently invaded upper Danube River were contrasted and differential trophic niche occupation was assessed. Only about 4% of analyzed gobies qualified as potential sneakers which may be explained by the recent and ongoing invasion process. This study provides evidence for the occurrence of sneaking behavior of invasive round goby in the upper Danube River.

Morphometric variability in round goby Neogobius melanostomus (Perciformes: Gobiidae) from the Sea of Azov

2017 ◽  
Vol 26 (2) ◽  
pp. 392-405 ◽  
Author(s):  
O.A. Diripasko ◽  
T.A. Zabroda
Keyword(s):  
Round Goby ◽  
Joint Effect ◽  
Neogobius Melanostomus ◽  
Sea Of Azov ◽  
Morphometric Characters ◽  
One Dimensional ◽  
The Sea Of Azov ◽  
Size Dependent ◽  
Size Variability ◽  
Males And Females

A total of 38 morphometric characters of the round goby Neogobius melanostomus melanostomus (Pallas, 1814) were studied in its native range in the Sea of Azov. The aim was to assess joint effect of sexual dimorphism and size variability on overall variability within groups of samples (populations) using appropriate methods of traditional statistical analysis (one-dimensional and multivariate statistics). Sex and size-dependent variability was studied based on model samples of males and females of different size. Most of the studied morphometric characters of round goby from the Sea of Azov demonstrated statistically significant sex- and size-dependent in-group variability. The pattern of the variability suggests that, for a comparison of round goby from different sea regions and between populations, separate samples of males and females within the range 9–13 cm SL should be examined in order to minimise the effect of the size and sex factors. The approach of searching for the most informative size range could be useful not only for further studies of infraspecific variation but for comparisons between morphologically close gobiin species.

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