ReShore: aquaculture breakwaters to protect coasts, produce food and rebuild ecosystems

ReShore is reinventing breakwaters, by incorporating aquaculture to make coastal protection more biodiverse and economically attractive.

Research has shown that, like other coastal vegetation such as mangroves and seagrass beds, seaweed aquaculture can reduce soil erosion and lessen the impact of big waves before they hit the shore.

At the same time, traditional engineering solutions like seawalls and breakwaters have several downsides: they are expensive to build and maintain (and getting more expensive due to rising sea levels and bigger storms), and they can contribute to soil erosion and habitat loss.

Is it possible to get the triple-win of protecting shorelines effectively, while getting the ecological benefits reefs and coastal vegetation bring, and at the same time reducing costs and even making a profit through seaweed and shellfish aquaculture?

That is the question ReShore is trying to answer.

A floating, living breakwater

Founded in The Netherlands in 2020 by Mitchell Williams and Frej Gustafson, ReShore has designed a floating, living breakwater. The breakwater exists of a series of 15-meter-long tubular pontoons floating on the water. The tubes are notched and grooved, creating habitat for animals, plants and algae. On either side, seaweed lines further anchor the breakwater. Below water, shellfish cages hang from the pontoons.

Adding seaweed and shellfish to the breakwater should not only have economic benefits, but it can also increase biodiversity and improve water quality. When it comes to how effective their solution is to soften the power of storm waves, Frej Gustafson reckons it’s too early to say.

“What we can say is that we’re comparable to current solutions. But there isn’t really a benchmark for floating structures like ours. For static structures the benchmark is at 90% wave attenuation – we’re far below that. So we don’t think this invention will immediately replace the first coastal defense. It is a system that can prove its worth especially in estuaries.

What I can say, however, is that adding aquaculture actually makes the structure more effective at breaking waves. Floating structures move a lot, and adding the aquaculture helps to keep it more stable.”

Finding a market

Gustafson is quick to add that a lot of questions remain with the culture system as the difference in biomass can be significant pre- or post-harvest, but he is confident that the technology can be worked out. The biggest challenge he sees in finding a market. The startup is looking at places where floating breakwaters are already in use today, like ports, marinas and harbours, and moving beyond that, fish farms as well as dredging companies that implement large-scale coastal protection.

ReShore is currently enrolled in the StartLife accelerator, having just finished testing their scale model. They are now readying themselves for a seed round in early 2022 to bring the prototype to open water for real-world testing.