The integration of a 600ha floodplain to the stream corridor of the tidal freshwater Scheldt Estuary will increase populations of eurytopic and rheophylic b species

Breine, J.

Maes, J.

Ollevier, F.

Stevens, M.

Open Marine Archive

Herrier J.-L., J. Mees, A. Salman, J. Seys, H. Van Nieuwenhuyse and I. Dobbelaere (Eds). 2005. p. 637-639  
Proceedings ‘Dunes and Estuaries 2005’ – International Conference on Nature Restoration 
Practices in European Coastal Habitats, Koksijde, Belgium, 19-23 September 2005 
VLIZ Special Publication 19, xiv + 685 pp. 
- 637 - 
New perspectives for fish in the Scheldt Estuary 
Joachim Maes1, Jan Breine2, Maarten Stevens1 and Frans Ollevier1  
1 Laboratory of Aquatic Ecology, Katholieke Universiteit Leuven 
Ch. De Bériotstraat 32, B-3000 Leuven, Belgium 
E-mail: Joachim.maes@bio.kuleuven.ac.be 
2 Institute for Forestry and Game Management 
Duboislaan 14, B-1560 Groenendaal, Belgium 
Abstract 
The integration of a 600ha floodplain to the stream corridor of the tidal freshwater Scheldt Estuary 
will increase populations of eurytopic and rheophylic b species. 
Keywords: Estuarine fish community; Controlled floodplain; Habitat restoration. 
Introduction 
After severe flooding in 1976, a flood prevention plan was developed to protect the tidal 
Scheldt catchment from new calamities. The plan comprised the construction of 512km 
dikes, 1133ha controlled floodplains and a storm surge barrier. The largest floodplain 
(578ha) is now under construction on the west bank of the river at Kruibeke, Bazel and 
Rupelmonde. The integration of the floodplain to the stream corridor is expected to 
significantly alter the structure and abundance of different fish populations in the river. 
Using different life history characteristics of estuarine fish species, we attempt to make a 
qualitative assessment of future changes to the species composition.  
Reference condition 
The fish community of Western European lowland rivers under tidal influence consists 
of about 20 rheophylic species, showing a particular preference for slow running, 
warmer water (Table I). Rheophylic A (RA) species use only the channel and the 
riparian zone. Examples include anadromous lampreys, salmonids, shads and sturgeon. 
RA cyprinids are mainly restricted to headwaters and are uncommon in lowland rivers. 
Apart from the river lamprey Lampetra fluviatilis, most species are absent in the tidal 
freshwater reach of River Scheldt due to population extinctions, migration barriers, 
spawning habitat reduction and overall pollution. Rheophylic B species (RB) include 
burbot, loaches and some cyprinid species. The species make essential use of backwaters 
along the river during their life history. Only Leuciscus idus is a typical member of a 
lowland river fish community but it occurs only sporadically in the Scheldt Estuary. 
Joachim Maes et al. 
- 638 - 
Rheophylic C species (RC) are confined to slow running brackish waters. These species 
are frequently caught in the river. Eurytopic species (E) do not have particular habitat 
demands. In dry periods, marine fishes may penetrate this zone while also typical 
limnophylic fish preferring lentic waters can be found. Both groups are not considered 
here. 
 
Table I. Reference fish fauna for a tidal fresh water estuary with respective life cycle 
category and spawning habitat [for abbreviations, see text; relative abundance 
based on average daily fyke net catches in the Scheldt at Antwerp (4: >1 fish 
day-1; 3: >1 fish week-1; 2: >1 fish month-1; 1: >1 fish year-1; 0: not present); 
expected change in the population size after integration of the floodplain to the 
river corridor (+: increase; 0: no change)] 
Species name Abundance Life cycle Spawning habitat Expectation 
Abramis brama 3 E plant or substrate + 
Acipenser sturio 0 RA gravel 0 
Alosa alosa 0 RA gravel 0 
Alosa fallax 0 RA midwater 0 
Anguilla anguilla 4 E ocean 0 
Coregonus oxyrinchus 0 RA midwater 0 
Esox lucius 0 E plant + 
Gasterosteus aculeatus 4 E nest + 
Gymnocephalus cernuus 2 E gravel + 
Lampetra fluviatilis 1 RA gravel 0 
Leuciscus idus 1 RB plant or substrate + 
Liza ramada 1 RC ocean 0 
Osmerus eperlanus 3 RC sand 0 
Perca fluviatilis 3 E plant or substrate + 
Petromyzon marinus 0 RA gravel 0 
Platichthys flesus 4 RC ocean + 
Pungitius pungitius 1 E nest 0 
Rutilus rutilus 3 E plant or substrate + 
Salmo salar 0 RA gravel 0 
Salmo trutta 0 RA gravel 0 
Silurus glanis 0 E soft bottom 0 
Stizostedion lucioperca 2 E nest 0 
Future development of the fish community 
We expect that the floodplain will autonomously develop into a fish nursery as long as 
permanent aquatic habitats are provided: small ponds and creeks are refugia to which 
juvenile fishes withdraw once the flood water is drained to the main river channel. The 
increased availability of spawning and nursery habitat is predicted to result in a notable 
increase of the total fish density in the oligohaline and freshwater parts of the estuary. 
The addition of inundated areas to the stream corridor particularly favours RB species 
such as ide (Leuciscus idus), which is now virtually absent in the Scheldt Estuary. 
Measures that support the recovery of the ide population may therefore be successful. 
New perspectives for fish in the Scheldt Estuary 
- 639 - 
However, not all species are likely to increase in abundance. Anadromous fish such as 
Lampetra fluviatilis and salmonid species will not benefit from increased habitat 
diversity since their distribution is limited to the main river channel. 


New perspectives for fish in the Scheldt Estuary

Abstract

Similar works

Full text

Available Versions

Open Marine Archive