There are fewer and fewer mussels, oysters, starfish; and more in the waters north of Groningen
The province of Groningen wants to begin a trial using ‘reef blocks’ along the Eemshaven-Delfzijl seawall to help reverse alarming patterns of sealife decline in the area. Shellfish, and other sea urchins might be able to grow on the new ‘reef blocks’, but the province of Groningen also wants to try to make the waters of the Ems-Dollard cleaner, reports the GIC.
The hard surface of the new blocks would mean that mussels and oysters can attach themselves and begin to build a new reef. At the same time, the province wants to make the water in the Ems less cloudy and polluted, creating greater opportunities for the development of shellfish and life on the sea floor.
The reef blocks are made from dredged silt, taken from the Ems-Dollard. The trial is intended to show whether the shellfish will return and create a new habitat for underwater nature. The province of Groningen and the Wadden Fund are supporting the trial, with a 240,000 euro subsidy.
There are fewer and fewer shellfish in the Ems-Dollard and Wadden Sea. This affects other animals that depend on them for food or settlement. Shellfish such as mussels and oysters are also called ‘biobuilders’, as they settle as a group in one place and build a new habitat for underwater animals and plants there.
Improving water quality
By removing silt from the water of the Ems-Dollard and processing it into nature-friendly reef blocks, the estuary will probably become less murky. Animals and plants in this unique and rare nature reserve have a hard time because of the silt-rich, oxygen-poor water. By removing a large amount of silt from the water every year, the water quality and ecology in the Ems-Dollard will hopefully improve.
Explore reef blocks
Dredging specialist NETICS is the inventor of the reef blocks. A contractor combination of NETICS, Van Oord and KWS Infra is making and installing the reef blocks and investigating the effects. Their joint research should clarify whether the reef blocks are causing an increase in shellfish and ‘benthic life’ in the nature reserve. The research results are expected in 2026. The acquired knowledge is to be exchanged with Waddenmosaiek, which investigates the underwater life in the Wadden area. The trial is supported by Groningen Seaports.
Rijke Dijk improvements
In the Delfzijl-Eemshaven dyke improvement, facilities have been installed near the Rijke Dijk that are good for birds, mussels and other animals and plants. The transition between land and water has been made more nature-friendly with a pile forest and tidal pools. Water remains in these tidal pools at low tide. This makes it an attractive natural habitat for fish, algae and other marine life. The reef blocks complement these measures.
Image via the GIC
