Dutch House Infrastructure and Water Affairs Committee Holds First Off-Site Meeting, Focusing on the Future of Grevelingenmeer and a 252,000-Tonne Manila Clam Resource

The Dutch House of Representatives Infrastructure and Water Affairs Committee met on Monday, November 2, in the municipality of Schouwen-Duiveland on the future of Grevelingenmeer. This was the first time in the history of a Dutch House committee that an off-site meeting was held in a provincial area, with Schouwen-Duiveland hosting the meeting.

Grevelingenmeer, located between the provinces of Zeeland and South Holland, is the largest saltwater lake in Western Europe. The lake has limited water exchange, which continuously leads to oxygen depletion. Restoring tidal movement is considered capable of restoring Grevelingenmeer. By widening the flow cross-section of the Brouwersdam, the tidal range could increase from 6 cm to 40 cm, thereby eliminating oxygen depletion in the deep-water areas of Grevelingenmeer. The cost of this plan is estimated at EUR 850 million, but Minister Karremans has removed it from her list of priorities.

The meeting was chaired by Pieter Grinwis (CU), and MPs from CDA, VVD, CU, D66 and BBB held discussions in three successive rounds with users, the government and experts on the future of Grevelingenmeer. Kees van Beveren (chairman of the Dutch Oyster Association) addressed the MPs on behalf of the fishing sector.

Van Beveren said: "Our message is: invest in a healthy (saltwater) Grevelingenmeer and give the shellfish farming industry and professional fishing in Grevelingenmeer a future. This can be achieved by allowing limited tidal movement in Grevelingenmeer in a controlled manner." He noted that the issue has been discussed for twenty years. His call for concrete steps in the short term received broad support.

Fishing activities in Grevelingenmeer include eel and lobster fishing, oyster farming on the bottom, and mussel rope cultivation. Due to the presence of hundreds of seals, eel fishing has almost disappeared. Oyster farming in Grevelingenmeer has deteriorated to the point where oyster farming is no longer considered profitable.

In addition to concerns about the oyster fishery and the fixed-gear fishery, Van Beveren also sees a new reality taking shape and bringing opportunities. The Manila clam (菲律宾帘蛤, Ruditapes philippinarum) has spread significantly; the population in Grevelingenmeer in 2025 is estimated at approximately 25.2 million kg. The Shellfish Policy 2023-2033 provides room to study whether fishing is possible, with scientific justification and ecosystem protection as the leading principles. The professional fishing sector in Grevelingenmeer requests room for a Manila clam fishing pilot. Fishing rights holders have jointly established Coöperatie Tapijtschelpen Grevelingenmeer for this purpose. A permit application will be submitted this year.

Only the speaker from ZLTO advocated the option of desalinating Grevelingenmeer, i.e., introducing Rhine water on the eastern side. The freshwater supply for agriculture in Schouwen-Duiveland could be achieved through a pipeline from Volkerak Zoommeer.