Site details

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5 stars - Fully protected as a national park or Natura 2000 site by national legislation
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Vast soft-sediment tidal flats in Oosterschelde. Photo: NIOO-CEME

Synoptic description of site:

Sea-arm in SW Netherlands, relatively free from anthropogenic input.

Extensive description of site:

The national reserve Oosterschelde (South-west Netherlands) is a 40 km long sea-arm with a maximum depth of 40 m and constant salinity of 29 to 30 ppt. It is a former estuary, detached from its river input since 1987, and protected form the sea by a moveable barrier that allows input of seawater. Only in the case of storm-surges will it be closed.

Habitats present:
Seagrass bedsX

Description of fauna and flora:

The fauna and flora, typical for shallow coastal seas and estuaries, are well documented, and have been studied since 1959 when the NIOO-CEME started to monitor the consequences of the construction of a series of strengthened dikes and barriers in SW Netherlands (the Delta project to protect against storm surges).

Human impact:

Since the area is detached from its riverine input it has a low level of pollution. The (small) cities and villages near the Oosterschelde (in total less than 100,000 inhabitants) have a strict treatment of municipal wastes. Strong activities of shellfish (mainly blue mussel) culture (on the soft sediment) are employed in the area.


All facilities for marine biodiversity research are available: a seagoing research vessel, fully equipped laboratories, and sophisticated experimental facilities such as mesocosms and a flume tank.

Available database and website:

Species inventories and information on environmental factors are available in different databases, the most extensive on zoomacrobenthos in the BIS (Benthos Information System) database at NIOO-CEME (, and on abiotic factors at RWS-RIKZ (

Datasets covering this area:


Commitment and ongoing research:

The Centre for Estuarine and Marine Ecology of the Netherlands Institute of Ecology (NIOO-CEME), based in Yerseke, has ongoing research in the Oosterschelde regarding several ecological topics, including biodiversity. It is funded by the Royal Netherlands Academy of Arts and Sciences, and able to commit itself to long-term research on European marine biodiversity issues.