Royal Netherlands Institute for Sea Research

KEE_Growth potential of Cockles in the Ems estuary

Double Dike

To improve the primary breakwater Eemshaven-Delfzijl the concept of ‘Double Dike” was introduced. Through artificial devices in the existing dike, tidal water from the Eems Dollard is let in and out. Taking advantage of opportunities that arise in the area in between the dikes, silt extraction, natural development, saline agriculture and aquaculture will be implemented. With the Double Dike, the province of Groningen wants to demonstrate the efficiency of the commercial exploitation of saline agriculture and aquaculture. They consider a possible scaling up to suitable areas in the coastal zone of the north of the Netherlands (and beyond).

Edible Cockle

Culturing cockles and seeweed

The province of Groningen has asked the NIOZ (in collaboration with WaddenWier) to conduct an integrated laboratory and practical study investigating possibilities and conditions for culturing and seaweed between the dikes. To achieve this, the water and silt quality in the Eems Dollard must be determined on the spot. Based on these and other relevant environmental conditions, research into the cultivation of cockle and seaweed should take place. As to cockle growth, we must examine the effects of the substrate (sand, silt). As to seaweed, we must investigate whether seaweed is suitable as a natural filter for silt and cockle nutrients. The practical test for the combination of cockles, seaweed and sludge should be carried out in polder Wassenaar (Texel) as a hydrological field laboratory.

Research components

In the meantime, the research has started; it consists of the following components:

A. Water quality research

B. Investigation of soil substrate effect on cockle growth

C. Research into the conditions for the use of seaweed in the Double Dike

D. Practical scale test


In this project NIOZ collaborates with Texel Saline (WaddenWier) and Meromar Seafoods BV.

Project information
Linked key area:
1 Jun 2016 - 31 Oct 2016

Meet the team

Philippart, Katja
Senior Scientist
Nauta, Reinier
Research Assistant
Folmer, Eelke
Independent Contractor