Atlantic horse mackerel among the mussel ropes
The impact of offshore aquaculture on the general health of the ocean is to be explored in a new project awarded funding by the UK Government.
The Ropes to Reefs project will assess the wider benefits of the UK’s first large-scale offshore mussel farm, located in Lyme Bay off the south coast of Devon.
In particular, it will examine whether the farm has resulted in benefits for the area’s biodiversity and productivity, and also investigate its impacts on the habitats of other important fish species.
The results of the £870,000 project will help to inform ecosystem-based fisheries management into the future.
Ropes to Reefs is one of 12 initiatives - - designed to support sustainable fisheries management that have received funding as part of the fourth and final round of the Fisheries Industry Science Partnership (FISP) scheme, part of the Government’s UK Seafood Fund.
It will be led by experts in marine conservation at the University of Plymouth, who have decades of experience in using innovative techniques to monitor the marine environment.
In particular, it will build on a long-running partnership between the University and Offshore Shellfish Ltd, and will utilise the unique before and after ten-year dataset – generated through PhD studentships supported by the company – that has been collected throughout the development of the farm.
That long-term partnership will also work with other organisations directly involved in the UK offshore aquaculture industry, including Scallop Ranch Ltd and local seaweed farmer Biome Algae, along with the Shellfish Association of Great Britain, the Marine Management Organisation, the Fishmongers' Company's Fisheries Charitable Trust, Devon and Severn Inshore Fisheries and Conservation Authority, and Natural England.
It also complements the University’s ongoing work to monitor the Lyme Bay Marine Protected Area (MPA), designated in 2008 and the first and largest MPA of its kind in the UK.

“Offshore mussel farming has the potential to become one of the world’s most sustainable, large-scale sources of healthy protein. Through the Ropes to Reefs project, we can gauge the industry’s potential benefits far beyond just providing a sustainable source of food. Working closely with the fishing and mussel farming industry, and building on previous and ongoing research, we can deliver essential evidence regarding the impact of offshore aquaculture. This will enable us to fully assess whether it can serve as a nature-based solution that preserves – if not enhances – the health and productivity of our ocean.”

Emma SheehanEmma Sheehan
Associate Professor of Marine Ecology and lead of the Ropes to Reefs project

The project will use cutting edge, cost-effective and non-destructive remote sampling techniques to monitor the seabed and ocean, under and around the farm.
This technology includes an automatous surface vessel fitted with a state-of-the-art multibeam sonar, along with ground truthing cameras deployed from local fishing boats, both of which will produce high resolution data.
Researchers will also use technology developed through the FISH INTEL project, another initiative led by the University, to track fish and crustaceans using acoustic tags via the world's first multi-farm aquaculture telemetry network.

The suspended rope culture offshore mussel farm in Lyme Bay has been designed to produce thousands of tonnes of sustainably farmed mussels from a relatively small area, which is less than 1% of Lyme Bay. During the past nine years of operation, we have witnessed the regeneration of biodiversity in the farmed area and huge increases in the number of fish and shellfish such as bass, mullet, crab and lobster. These benefit from habitat, shelter, nursery areas and food that is freely available around the ropes in the farm. The Ropes to Reefs project will provide evidence to determine whether the offshore mussel farm provides an enhancement effect to surrounding commercial fisheries, as the other species spill over from the protected area. It will also establish whether food produced by this type of aquaculture acts as an addition and not a replacement to traditional fisheries.

John Holmyard, Managing Director of Offshore Shellfish Ltd

Could offshore mussel farms have wider environmental benefits?

A study led by the University, published in 2022, suggested that in addition to helping meet global fish consumption demands, there is also the potential for the offshore shellfish industry to have wider benefits for the marine environment. In addition to growing on the ropes, mussel shells were first observed on the seabed under the lines after just six months. Both the size of mussel clumps and the percentage cover of shells under the farm increased over time and this in turn led to increases in the abundance of other species.
Mussels - getty - Plymouth pioneers