|Oyster dislodgement thresholds under hydrodynamic forces|
Breunesse, S. (2019). Oyster dislodgement thresholds under hydrodynamic forces. BSc Thesis. NIOZ Netherlands Royal Institute for Sea Research: Yerseke. 41 pp.
Ostrea edulis formed important large-scale reefs on the sandy North Sea floor before the 19th century. However, these declined due to overexploitation, habitat degradation and parasitic infection. Now an innovation site of Borssele offshore wind park is assigned to combine the wind turbines with the restoration of these long-lost oyster reefs. The problem is that there is little information on how to restore these reefs. This research report looks at the knowledge gap about oyster dislodgement thresholds by providing flume studies analysing the dislodgement probability at different flow velocities, oyster densities and spatial distribution. Other that, the interaction between the oysters and the stability sand is studied. The results indicate an unexpected relation of a higher velocity having higher dislodgement thresholds and suggest that higher densities increase the dislodgement thresholds as well. In the end, the dislodgement thresholds itself could not be concluded since the hydrodynamic force did not go high enough in the experiments to reach the full dislodgement threshold (i.e. all oysters dislodged).