Mussel farm weathers the storm with innovative floatation system

Initial implementation of a new mussel farm flotation system has proven successful in producing shellfish at exposed sea sites, according to the system’s developers, Offshore Shellfish Ltd and Fusion Marine Ltd.

The system has helped Offshore Shellfish Ltd (OSL) to become Europe’s first company to install a broad-scale, rope-grown mussel farm in fully offshore conditions. The farm is located approximately three to six miles off of the South Devon in Lyme Bay in Great Britain, where it has been a challenge to create a lasting and effective floatation system for mussel aquaculture that can handle the tumultuous winter weather.

With the outline of a float design concept in mind – one that operates in a vertical position instead of the typical horizontal-axis barrel configuration commonly used in mussel farming – OSL’s managing director John Holmyard turned to Fusion Marine for assistance in honing his idea.

“We had worked with Fusion Marine before and trusted them to translate our ideas into a durable float of a specific shape and size that would ride the waves and reduce movement on the mussel lines ensuring that the crop does not fall off,” said Holmyard in a prepared statement.

The 250-liter floats incorporate high density polyethylene (HDPE) and feature injection-moulded ends with connections that are butt-fused onto a length of large diameter HDPE pipe, explained OSL. As a result of this setup, the system is anchored by strong rope connection points that provide secure and standardized attachments of the floats to headlines. The robustness of the floats allow for submergence if necessary, meaning that extreme forces weathered by the system aren’t transferred to the mussel ropes, preventing their displacement.

Overall, the system allows for better growing conditions and increased harvests, noted Holmyard.

“During extensive trials, we have been thrilled with the performance of the flotation system, which has enabled the farm to produce a crop of high-quality, fast-growing mussels that are in great demand,” he said. “Initially, the floats were not the simplest to use, but we have been learning how they work during two years of trial and sometimes error, and have now perfected the design and the way we use them. These floats now do exactly the job they were designed to do, and are doing it very well. I don’t believe the farm would have survived the past two winters’ storms without them.”

The collaborative efforts of OSL and Fusion Marine have resulted in a farming technique that works to ensure operations maintain their integrity, and allows for them better compete in the sector, said Rhuaraidh Edwards, technical sales engineer for Fusion Marine. 

“We have worked closely with OSL to develop this robust and versatile flotation system for demanding offshore sites,” Edwards said. “The floats have a unique spliced loop attachment system, which ensures that each rope can be quickly and easily attached in the same way and at the same depth, with no knots to tie and nothing to work loose. This, combined with the vertical axis design, ensures the farm can cope with harsh offshore sea conditions.”

The system is undergoing its build-out phase, having supplied 700 floats so far. The companies expect that completion of the floatation mechanism will come in four years’ time, at which time OSL expects to produce 10,000 metric tons of mussels annually.

“Throughout the development process we have been impressed by John Holmyard’s pioneering spirit for new aquaculture innovation and we continue to work closely with him to further develop the offshore float for his exciting but very demanding venture,” Edwards said.


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