Coastal defense through the construction of mussel beds

General introduction

Mussels show potential as biobuilders for a coastal protective natural reef, when a traditional aquaculture setup for mussel farming gets a smart adaptation, such as a "Musselshaker". That is one result from the Coastbusters 2.0 project. In the coastal strip of the Belgian North Sea, experiments were set up for this purpose with various reef-facilitating systems that promote the early stages of mussel beds. The long-term goal was the development of biogenic reefs that grow into a (semi-)natural coastal system capable of providing certain ecosystem services such as coastal protection.
Increasing climate changes and the associated rising sea level, intense storms and beach erosion, all point to the urgent need for good coastal protection measures. Current engineering approaches with both hard and soft measures fall short of efficient and cost-effective coastal protection. The development of three-dimensional living structures created by dense aggregations of organisms (such as mussels or seaweeds) could be a useful additional tool in the overall coastal protection concept. 

Research approach

These research questions arise regarding the use of mussel beds as coastal defense: To what extent can biodegradable materials be used instead of conventional materials and textiles as construction components for an offshore mussel cultivation installation? What is the most appropriate technical, spatial and temporal design of the offshore setup to efficiently achieve biogenic bank formation and mussel survival and under different hydrodynamic conditions? How can the use of advanced observational techniques lead to improved, scientific monitoring of the formation and evolution of these mussel banks? What are the preconditions for the formation and survival of such newly formed banks? What is the added value to biodiversity and ecosystem services and goods of these artificial mussel banks? ILVO's contribution was to scientifically determine the preconditions and added ecosystem values and services. ILVO also formulated substantiated advice around the design of the offshore setup, as it is inspired by existing expertises in terms of mussel culture practices.

Relevance/Valorisation

Coastbusters 2.0, as a public-private innovation partnership, has succeeded in developing a new innovative approach: nature-based solutions for generating ecosystems on a large scale, including coastal protection. Specifically, the creation of non-artificial (biogenic) reefs using mussels (Mytilus edulis) shows promise. Experiments at two research sites (one quite sheltered and one with more exposed environmental conditions near De Panne) confirm the potential of bivalves as biobuilders for biogenic reefs. The 'Musselshaker,' an adaptation to traditional hanging mussel setup that promotes the dropping of new mussels to the bottom each time, appears to be affordable, biodiversity-promoting and an easy-to-install stand-alone system that can be implemented in numerous marine construction projects.
The tested filamentous dropper line material had good adhesion and growth stimulus for the baby mussels. Innovative monitoring methods were developed and proved efficient for the Coastbusters installation. The significant variability observed, both within and between years, underscores the need for adaptable management strategies (Mazharul et al., 2024). Detailed and highly technical monitoring is important to understand the dynamic and challenging nature of the study sites (Boulanger et al., 2024). Understanding the ecological nuances of biogenic reefs remains a challenge. Understanding of those nuances is crucial to the complex management of young, human-initiated, natural reefs (Semeraro et al., 2024).

Funding provider(s)
VLAIO