Artificial reef construction

Building specific coastal habitats to maintain marine resources in Corsica

Person in charge:

Sylvia Agostini

Problematic issues

In the context of loss of marine biodiversity and constant decline in exploitable resources, the management of the seabed by artificial reefs to improve biological productivity for fishing and the maintenance of fishery resources, is a major challenge for sustainable development in the years to come. In a world where the population is expected to grow by 2 billion by 2050, we must begin today to meet the global food challenge whilst preserving the good state of natural resources. The artificial reef appears to be an important ecological engineering tool for the preservation, or even restoration, of the marine environment. Although the efficiency of reefs is no longer to be proven in terms of increased diversity, density and biomass of marine species, there is no model the same. Indeed, the environmental conditions, administrative systems and management methods are so numerous that the modelling of such devices is still forward-looking. Scientific research is only beginning to offer comprehensive recommendations (for example on the shape of structures) to reduce errors and costs. Overall, everything remains to be done and tested. The University of Corsica thus plans to focus part of its innovative work on this problem which concerns the design and testing of artificial reefs of the micro-habitat type. Our research proposes to focus specifically on the essential habitats that are nurseries, aimed mainly at maintaining marine biodiversity and/or supporting populations of fish species of interest (economic or heritage) at the juvenile stage.

Objectives

The interest is to be able to offer by way of these nurseries a tool for the management of fishery resources intended for local authorities, maritime professionals and environmental managers. It aims to increase or even maintain local marine biodiversity and fish populations that are subject to economic or recreational exploitation. These tools will be essential to both maintain (or even increase) the density of local populations, but also to offer complementary habitats in the environment likely to participate and promote the natural grouping and survival of wild or farmed juvenile species. The project also proposes to develop “specific” micro-habitats adapted to species of interest for the creation of fishing zones and for the aquaculture profession which wishes to move towards polyculture. The main objective of the project is to support: (i) fishing activities by maintaining marine resources through ‘artificial’ structures targeting species of interest; (ii) aquaculture activities by proposing new polyculture techniques; and (iii) maintenance of marine biodiversity by proposing a new tool for environmental managers. Thus, the ‘micro-habitat’ type reefs (small size) developed within the Stella Mare platform for juvenile stages are what it is essentially aimed at.

• THE RESTORATION OF DEGRATED HABITATS: This approach is based on concepts of ecological engineering, and a return to a better ecological state through so-called « artificial » means, by restoring the habitat conditions necessary for the development of marine species, a relevant objective when the original conditions for the good state of marine biotic communities have been degraded, under the action of anthropic factors (coastal development, overfishing...)
• MAINTENANCE OF BIODIVERSITY: These habitats adapted to the early stages of development will increase the survival rate of fish species in the face of natural predation.
• MAINTENANCE OF FISHING ACTIVITIES: This concept aims to develop fishing potential in areas that are easily accessible but not very productive in terms of fishery resources, aiming to produce biomass and increase the specific diversity of target species representing commercial value.
• SUSTAINABLE AQUACULTURE: Developing polyculture techniques for better environmental management of production sites while increasing economic benefits for aquaculture producers.
• RESEARCH AND DEVELOPMENT: Setting up a specific field of experimentation to analyse the evolution of marine biotic communities in an environment. Such development may be aimed at improving and acquiring scientific knowledge on the behaviour at the early stages of development, or for the testing of new prototype reefs.

Steps to be taken

Our programme, which brings together several objectives (restoration and/or protection of marine biotic communities, fisheries production, research and development, recreational and/or educational), will be structured according to the following stages:

• Conception and design of dedicated structures
• Construction with testing of different materials
• Laboratory testing of prototypes
• Immersion and scientific monitoring on site for conclusive tests
• Estimation of the ecological gain for specific areas and costs/efficiency of the structures
• Technology transfer to authorities

It will primarily concern the design of artificial reefs specific to the species studied within the other programmes cited precedingly (sea urchin, lobster, dentex, fish), but may also concern other species of interest such as: the red lobster Palinurus elephas, the spider crab Maja squinado, and the common octopus Octopus vulgaris.