What is the impact of mussel seed fishing on the seabed, biodiversity and other natural values? Do benthic animals and fish suffer from mussel seed fishing or do they actually thrive as a result? How can you modify shellfish culture in the Wadden Sea to make it both more efficient and ensure healthy natural habitats? These and other questions were addressed in PRODUS, the research project on sustainable shellfish culture.
Mussel culture starts with very young mussels, known as mussel seed. Traditionally, this mussel seed is harvested from naturally formed mussel seed banks in the Wadden Sea. Mussel seed fishing requires a permit, as stipulated in the Fisheries Act. Because the Wadden Sea is a protected nature reserve, a permit is also required under the terms of the Nature Conservation Act (NCA). According to these terms, it must be demonstrated that the fishing has no negative effects on the designated conservation objectives for the habitat type in which the fishing takes place.
Because these effects were unclear, PRODUS was established. The research within PRODUS concerns the effects of mussel seed fishing on the natural values of mussel banks. To determine these effects, a comparison was made between the biodiversity on wild mussel banks and on parcels with cultured mussels. For this purpose, the research focused on benthic animals, fish stocks and the composition and structure of the seabed. When measuring the effects, a distinction was made between the spring and autumn mussel seed fisheries. The research was conducted on the banks where mussel seed fishing takes place. These are the sublittoral mussel seed banks, which remain under water at both high and low tide, in the western Wadden Sea. On these banks, 40 research locations, 8 ha in area, were established, each divided into two sections. During the study, one section was closed for mussel seed fishing and the other section was open.