Witbaard et al. 2013. The final report on the growth and dynamics of Ensis directus in the near coastal zone off Egmond, in relation to environmental conditions in 2011-2012.

The research presented here is meant to give basic insight into the seasonal variability of environmental processes and how these control the ecology and growth dynamics of Ensis directus in this near coastal zone.  Five questions were to be answered 1. What is the natural variation in silt concentrations close to the seabed 2. What is the forcing factor of this variation (erosion, advection, season) 3. Is the valve gape of Ensis directus related to the silt concentration and how (linear, stepwise) if not which other factors control the gape of Ensis. 4. Describe the growth of Ensis directus in terms of DEB variables. 5. What factors correlate the best with DEB growth variables of Ensis dir.

It was anticipated that with finding the answers on these questions the significance of the ecological effects of sand extraction and beach nourishment can be better estimated and understood.