VIS - Fishes in estuarine waters in Flanders, Belgium

Latest version published by Research Institute for Nature and Forest (INBO) on 13 April 2021 Research Institute for Nature and Forest (INBO)
Publication date:
13 April 2021
CC0 1.0

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VIS - Fishes in estuarine waters in Flanders, Belgium is a species occurrence dataset published by the Research Institute for Nature and Forest (INBO) and described in Brosens et al. 2015 (https://doi.org/10.3897/zookeys.475.8556). The dataset contains over 70,000 fish occurrences sampled between 1992 and 2012 from almost 50 locations in the estuaries of the river Yser and the river Scheldt, in Flanders, Belgium. The dataset includes 69 fish species, as well as a number of non-target crustacean species. The data are retrieved from the Fish Information System (VIS), a database set up to monitor the status of fishes and their habitats in Flanders and are collected in support of the Water Framework Directive, the Habitat Directive, certain red lists, and biodiversity research. Additional information, such as measurements, absence information and abiotic data are available upon request. Issues with the dataset can be reported at https://github.com/LifeWatchINBO/data-publication/tree/master/datasets/vis-estuarine-occurrences

Length and weight measurement data of the individual fishes, absence information, occurrence data since 2013, as well as abiotic data of the sampling points (pH, temperature, etc.) are not included in the Darwin Core Archive and are available upon request.

To allow anyone to use this dataset, we have released the data to the public domain under a Creative Commons Zero waiver (http://creativecommons.org/publicdomain/zero/1.0/). We would appreciate however, if you read and follow these norms for data use (http://www.inbo.be/en/norms-for-data-use) and provide a link to the original dataset (https://doi.org/10.15468/estwpt) whenever possible. If you use these data for a scientific paper, please cite the dataset following the applicable citation norms and/or consider us for co-authorship. We are always interested to know how you have used or visualized the data, or to provide more information, so please contact us via the contact information provided in the metadata, opendata@inbo.be or https://twitter.com/LifeWatchINBO.

Data Records

The data in this occurrence resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 54,469 records.

This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for download in the downloads section. The versions table lists other versions of the resource that have been made publicly available and allows tracking changes made to the resource over time.


The table below shows only published versions of the resource that are publicly accessible.

How to cite

Researchers should cite this work as follows:

Breine J, Verreycken H, De Boeck T, Brosens D, Desmet P (2014): VIS - Fishes in estuarine waters in Flanders, Belgium. Research Institute for Nature and Forest (INBO). Dataset/Occurrence. https://doi.org/10.15468/estwpt Data paper: https://doi.org/10.3897/zookeys.475.8556


Researchers should respect the following rights statement:

The publisher and rights holder of this work is Research Institute for Nature and Forest (INBO). To the extent possible under law, the publisher has waived all rights to these data and has dedicated them to the Public Domain (CC0 1.0). Users may copy, modify, distribute and use the work, including for commercial purposes, without restriction.

GBIF Registration

This resource has been registered with GBIF, and assigned the following GBIF UUID: 274a36be-0626-41c1-a757-3064e05811a4.  Research Institute for Nature and Forest (INBO) publishes this resource, and is itself registered in GBIF as a data publisher endorsed by Belgian Biodiversity Platform.


Occurrence; Observation; ecosystem functioning; fish-based index of biotic integrity; fish distribution; brackish water; estuary; LifeWatch; open data; River Scheldt; River Yser; Occurrence


Jan Breine
  • Metadata Provider
  • Originator
  • Point Of Contact
Research Institute for Nature and Forest (INBO)
Duboislaan 14
1560 Groenendaal
Brussels Capital Region
Hugo Verreycken
  • Originator
Research Institute for Nature and Forest (INBO)
Duboislaan 14
1560 Groenendaal
Brussels Capital Region
Tom De Boeck
  • Originator
Research Institute for Nature and Forest (INBO)
Kliniekstraat 25
1070 Brussels
Brussels Capital Region
Dimitri Brosens
  • Metadata Provider
  • Originator
Data liaison officer
Research Institute for Nature and Forest (INBO)
Kliniekstraat 25
1070 Brussels
Brussels Capital Region
Peter Desmet
  • Metadata Provider
  • Originator
Data lab coordinator
Research Institute for Nature and Forest (INBO)
Kliniekstraat 25
1070 Brussels
Brussels Capital Region

Geographic Coverage

Flanders is one of the three administrative regions in the country of Belgium, located in the centre of Western Europe. The Flemish region is situated in the north of the country and covers an area of 13,522 km² (44,29% of Belgium). Belgium has a temperate maritime climate that is influenced by the North Sea and the Atlantic Ocean with substantial precipitation in all seasons. The summers are moderate and the winters are mild. The two main geographical regions of Flanders are the coastal plain in the North-West and the Central plain, further inland. With 470 inhabitants/km², Flanders is one of the most densely populated areas of Europe. The three major rivers are the River Yser, the River Scheldt, and the River Meuse. All rivers in Flanders flow into the North Sea, but only the River Yser drains directly into the sea within the jurisdiction of Flanders. The dataset comprises the estuaries of the River Scheldt, including tidal parts of the rivers Rupel, Durme, Zenne, Dijle and Grote Nete, and the River Yser. The River Scheldt is a 435 km long lowland river originating on the plateau of Saint-Quentin near Gouy, a small town in the French department of Aisne. The river enters Belgium close to Tournai. Then the river turns east, in the direction of Antwerp. After crossing the city of Antwerp, the Scheldt enters the Netherlands where it ends in the North Sea near Vlissingen. The tidal influence extends much further land inward than the freshwater-saltwater boundary. As a result, an extensive freshwater region under tidal influence is present. The tidal activity goes as far as Ghent, 160 km from the river mouth, where the tide is stopped by sluices. In the Zeeschelde (the Belgian part of the estuary), three zones are distinguished following the Venice system (1959): a mesohaline zone (5–18 g salt/kg) between Zandvliet and Antwerp, an oligohaline zone (0.5–5 g salt/kg) between Antwerp and Temse, including the Rupel tributary, and a tidal freshwater zone till Ghent including the Durme tributary. The marshes and mudflats create a valuable landscape for biodiversity. The Scheldt estuary is one of the last natural deltas in Western Europe and many areas near its riverbanks are marked as Natura 2000 areas (Figure 7). Especially its freshwater estuary areas are unique. The River Yser is a 78 km long river originating in Kassel, located in French Flanders. It enters Belgium in the province of West Flanders and drains into the sea near the town of Nieuwpoort. Sea and fresh water meet in an estuary, resulting in 130 hectares of tidal mud flats, salt marshes, dunes, beaches, and polders.

Bounding Coordinates South West [50.68, 2.54], North East [51.51, 4.59]

Taxonomic Coverage

The dataset contains 69 fish species found in the estuaries of the River Yser and the River Scheldt, as well as 9 non-target crustacean species. The class of Actinopterygii is most represented (67 species), along with two Petromyzontida. All the crustaceans in this dataset are from the order of the Decapoda.

Kingdom Animalia (animals)
Class Actinopterygii (ray-finned fishes), Petromyzontida, Malacostraca
Family Acipenseridae, Agonidae, Ammodytidae, Anguillidae, Atherinidae, Blenniidae, Callionymidae, Carangidae, Centrachidae, Clupeidae, Cottidae, Cyprinidae, Esocidae, Gadidae, Gasterosteidae, Gobiidae, Liparidae, Lotidae, Moronidae, Mugilidae, Mullidae, Osmeridae, Percidae, Pholidae, Pleuronectidae, Salmonidae, Scophthalmidae, Siluridae, Soleidae, Syngnathidae, Trachinidae, Triglidae, Zoarcidae, Petromyzontidae, Cambaridae, Cancridae, Crangonidae, Paguridae, Palaemonidae, Polybiidae

Temporal Coverage

Start Date / End Date 1995-04-01 / 2012-11-27

Sampling Methods

Standardized sampling methods were used as described in Belpaire et al. (2000) and Van Thuyne & Breine (2010) and are specified in the dataset as dwc:samplingProtocol. Per water body, the same method was used for each sampling event. The default method is paired fyke netting, which has been intercalibrated by the North East Atlantic Calibration Group, but additional techniques such as anchor netting, seine netting, pound netting, electric fishing, and eel fyke netting were used as well (Breine et al. 2011). All fishes were identified to species level, counted and their length and weight was measured. Fyke nets are relatively unselective fishing gear catching demersal and pelagic species (Hamerlynck and Hostens 1994) and also they are easy to install in a great variety of habitat types. As few studies compare fyke catches with other gear (e.g. Hinz 1989, Thiel and Potter 2001), we compared presence/absence data obtained with fyke nets with presence/absence data of fish impinged at cooling-water filter screens of the nuclear power plant of Doel situated in the study area. The data was collected in the same period between 1995 and 1998. During this period we collected the same species with both survey methods but the species richness per day per fyke net was generally higher than that obtained on the filter screens (Breine et al. 2007). In addition preliminary results from a gear intercalibration exercise in different estuaries in Ireland (Whyte et al. 2007) indicated that for species diversity, the results of fyke net catches are comparable to those obtained with other gear (beach seine, beam trawl, otter trawl).

Study Extent Over 2,000 locations in estuaries, inland rivers, streams, canals, and enclosed waters in Flanders, Belgium have been sampled, from March to November, since 1992. In 2001, these locations were consolidated in a monitoring network (“VISmeetnet”) of 900 sampling points. Four locations in the Yser estuary and 43 locations in the Scheldt were sampled since 1995. While the Yser estuary only covers a small geographical area, the Scheldt estuary is with 33,000 hectares one of the largest estuaries in Europe. It is also one of the few remaining European estuaries that includes the entire gradient from fresh to saltwater tidal areas (Van den Bergh et al. 2009). The 43 sampling locations in the Scheldt estuary are mainly located in the River Scheldt, but also in the Rivers Durme, Rupel, Dijle, Zenne and Nete. The geographic coordinates in the dataset are those of the defined sampling locations (dwc:locationID). However, as these coordinates are not always exact the actual coordinates of the catch, which may be located further up- or downriver, the coordinate uncertainty (dwc:coordinateUncertaintyInMeters) has been set to 250 meter.
Quality Control Strict field protocols where used. The Manual for Application of the European Fish Index (EFI) (Fame consortium 2004) served as a guideline for electrofishing and was used in support of the EU water framework directive.

Method step description:

  1. Water type: Estuaries Method: fyke fishing, anchor netting, pound netting, electric fishing Effort: Fykes: 2 paired nets for two successive days per site. Winged fyke: one per site for two successive days. Anchor netting: per site 4 surveys of one hour (two for each tide). Electric fishing: only in flood control areas (250 m shore transects/ha).

Bibliographic Citations

  1. Brosens D, Breine J, Van Thuyne G, Belpaire C, Desmet P, Verreycken H (2015) VIS – A database on the distribution of fishes in inland and estuarine waters in Flanders, Belgium. ZooKeys 475: 119-145. https://doi.org/10.3897/zookeys.475.8556 https://doi.org/10.3897/zookeys.475.8556
  2. Belpaire C, Smolders R, Vanden Auweele I, Erecken D, Breine J, Van Thuyne G, Ollevier F (2000) An Index of Biotic Integrity characterizing fish populations and the ecological quality of Flandrian water bodies. Hydrobiologia 434: 17–33. https://doi.org/10.1023/A:1004026121254 https://doi.org/10.1023/A:1004026121254
  3. Breine J, Simoens I, Goethals P, Quataert P, Ercken D, Van Liefferinghe C, Belpaire C (2004) A fish-based index of biotic integrity for upstream brooks in Flanders (Belgium). Hydrobiologia 522: 133–148. https://doi.org/10.1023/B:HYDR.0000029991.42922.a4 https://doi.org/10.1023/B:HYDR.0000029991.42922.a4
  4. Breine J, Maes J, Quataert P, Van den Bergh E, Simoens I, Van Thuyne G, Belpaire C (2007) A fish-based assessment tool for the ecological quality of the brackish Schelde estuary in Flanders (Belgium). Hydrobiologia 575: 141–159. https://doi.org/10.1007/s10750-006-0357-z https://doi.org/10.1007/s10750-006-0357-z
  5. Breine J, Quataert P, Stevens M, Ollevier F, Volckaert FAM, Van den Bergh E, Maes J (2010) A zone-specific fish-based biotic index as a management tool for the Zeeschelde estuary (Belgium). Marine Pollution bulletin 60: 1099–1112.
  6. Breine J, Maes J, Ollevier F, Stevens M (2011) Fish assemblages across a salinity gradient in the Zeeschelde estuary (Belgium). Belgian Journal of Zoologie 141(2): 21–44.
  7. European Commission (2007) Council Regulation (EC) No 1100/2007 of 18 September 2007 establishing measures for the recovery of the stock of European eel. Official Journal of the European Union 22.9.2007 L 248: 17–23.
  8. EU Water Framework Directive (2000) Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Official Journal 22/12/2000 L 327: 0001–0073.
  9. FAME Consortium (2004) Manual for the application of the European Fish Index - EFI. A fish-based method to assess the ecological status of European rivers in support of the Water Framework Directive. Version 1.1, January 2005.
  10. Hamerlynck O, Hostens K (1994) Changes in the fish fauna of the Oosterschelde estuary: a ten-year time series of fyke catches. In: Nienhuis PH et al. (Eds) The Oosterschelde Estuary (The Netherlands): a case-study of a changing ecosystem. Hydrobiologia 97: 497–507. https://doi.org/10.1007/BF00024651 https://doi.org/10.1007/BF00024651
  11. Hinz V (1989) Monitoring the fish fauna in the Wadden sea with special reference to different fishing methods and effects of wind and light on catches. Helgoländer Meeresunters 43: 447–459. https://doi.org/10.1007/BF02365903 https://doi.org/10.1007/BF02365903
  12. Karr JR (1981) Assessment of biotic integrity using fish communities. Fisheries 6: 21–27. https://doi.org/10.1577/1548-8446(1981)006%3C0021:AOBIUF%3E2.0.CO;2 https://doi.org/10.1577/1548-8446(1981)006%3C0021:AOBIUF%3E2.0.CO;2
  13. Thiel R, Potter IC (2001) The ichthyofaunal composition of the Elbe estuary: an analysis in space and time. Marine Biology 138: 603–616. https://doi.org/10.1007/s002270000491 https://doi.org/10.1007/s002270000491
  14. Van den Bergh E, Garniel G, Morris RKA, Barendregt A (2009) Conservation of tidal freshwater wetlands in Europe. In: Barendregt A, Whigham D, Baldwin A (Eds) Tidal Freshwater Wetlands (2009). Backhuys Publishers, Leiden, 241–252.
  15. Van Thuyne G, Breine J (2010) Visbestandopnames in Vlaamse beken en rivieren in het kader van het ‘Meetnet Zoetwatervis’ 2009. Rapporten van het Instituut voor Natuur- en Bosonderzoek, 2010 (42). INBO, Brussel, 196 pp.
  16. Venice system (1959) The final resolution of the symposium on the classification of brackish waters. Archo Oceanography Limnology 11: 243–248. http://www.aslo.org/lo/toc/vol_3/issue_3/0346.pdf
  17. Verbiest H, Belpaire C, Vandenabeele P, Ollevier F (1996) Het in werking stellen van de visdatabank met de nadruk op de gebruiksvriendelijkheid ervan IBW.Wb.V.R.96.042.
  18. Verbiest H, Vandenabeele P, Belpaire C, Ollevier F (1994) Ontwerp van de visdatabank en implementatie van historische en recente gegevens IBW.Wb.V.R.94.029.
  19. Verreycken H, Belpaire C, Van Thuyne G, Breine J, Buysse D, Coeck J, Mouton A, Stevens M, Van den Neucker T, De Bruyn L, Maes D (2014) IUCN Red List of freshwater fishes and lampreys in Flanders (north Belgium). Fisheries Management and Ecology 21: 122–132. https://doi.org/10.1111/fme.12052 https://doi.org/10.1111/fme.12052
  20. Whyte BI, Keirse G, King J (2007) WFD gear intercalibration: an exercise among five NEA GIG teams, October 2006. Report Central Fisheries Board Ireland, 30 pp.

Additional Metadata

Purpose The Fish Information System or VIS (http://vis.milieuinfo.be) is a database created by the Research Institute for Nature and Forest (INBO) which is used to monitor the status of fishes and their habitats in Flanders, Belgium and to calculate the biotic integrity (Karr 1981, Belpaire et al. 2000, Breine et al. 2004, 2007, 2010) of fish assemblages. It contains data regarding occurrences, individual morphometrics, stocks, pollutants, indices, and non-native fish species. Sampling has been going on since 1992, the database model was designed in 1994 (Verbiest et al. 1994), the first database developed in 1996 (Verbiest et al. 1996), and the consolidated database set up in 2001. VIS is used for supporting NATURA 2000, an ecological network of protected areas in Europe and to calculate the EQR (Ecological Quality Ratio) in the framework of the EU Water Directive (Directive 2000/60/EC). Further, the database provides updated information for Flemish Red Lists of fishes and lampreys (Verreycken et al. 2014) and on the distribution status of non-native and invasive fish species. The data are also crucial in fish stock management and for reporting on the status of the European eel stock as required by the Eel Regulation (Council Regulation (EC) N° 1100/2007). This dataset is a standardized extraction of all estuarine species occurrences from VIS.
Alternative Identifiers 274a36be-0626-41c1-a757-3064e05811a4