Response Of predators to Protection and Enhancement (ROPE)

Marine Conservation Research Group

Funded by the European Maritime and Fisheries Fund (£187,545), ROPE (Response of Predators to Protection and Enhancement) applies innovative acoustic tracking technology to understanding how the UK’s largest offshore rope-cultured mussel farm influences the movements of commercially important fish and crustaceans.

This project builds on the University of Plymouth’s long-term monitoring program which has been tracking conditions in Lyme Bay, South Devon for over a decade and has been monitoring the ecological effects of the offshore mussel farm since the beginning of its development in 2013. The mussel farm, operated by Offshore Shellfish Ltd and located between three and six miles offshore in Lyme Bay is expected to become the largest of its type in European waters covering a total area of 15.4 square km and producing up to 10,000 tonnes per year of native blue mussels.

“In the UK and worldwide there is increasing interest in the role of the ocean in sustainable food production and how best to manage ocean spaces for multiple uses. The mussel farms in Lyme Bay are located close to a marine protected area and locally important fishing grounds making it vital to better understand the ecological and economic implications”

Dr Simon Pittman, ROPE Research Project Manager, School of Biological and Marine Science, University of Plymouth

Our underwater monitoring surveys have shown that the farm which essentially exists as a living floating reef structure appears to be increasing the local abundance of marine species including brown crab, lobster and European seabass that inshore fishermen on the Dorset and Devon coast rely on for substantial parts of their income.

The vertically hanging ropes that are home to millions of blue mussels also attract fish and many other plant and animals that settle on the mussels. Underneath the ropes, crabs and lobsters feed on the mussel clumps that fall to the seabed. Although we know that crabs, lobsters and predatory fish utilise the site for food and shelter, due to the habitat enhancement that the ropes, moorings and fallen mussel clumps provide, we know very little about the movements of these predators around the farm, or how long they remain resident, or if there is movement between the farms and the MPA. By offering a refuge function the farm may complement the MPA in its role of replenishment of local fished populations and may induce spillover benefits into existing fishing grounds, but this all depends on the movements of individual animals.

To investigate animal movements in and around the mussel farm and between the mussel farm and the MPA, this project will tag and track multiple species including sea bass, brown crab, lobsters and crawfish for up to two years. The tags emit a unique coded ping which is recorded and monitored by static receivers placed underwater around the farm and the MPA boundary.

“The consequence of understanding the ecological role of the farm relative to the MPA will provide critical information for the future location and management of offshore aquaculture, MPAs and traditional fisheries.” Marine & Fisheries Directorate, Dept. Environment, Food & Rural Affairs

This unique project which works in collaboration with the fishing industry has received strong support from the seafood industry, marine conservation groups and government agencies with responsibility for effective marine planning and licensing. All sectors supporting the view that robust scientific evidence will improve our understanding marine ecosystems and is vital to underpin policies and strategic decisions for sustainable and responsible use of our oceans.

“Exploring whether this offshore aquaculture benefits from neighbouring marine protected areas and influences commercially valuable species is essential to comprehend in order to ensure a sustainable future for this industry” Shellfish Association of Great Britain

Location of the Offshore Shellfish Ltd. mussel farm in Lyme Bay

Dr Emma Sheehan, Senior Research Fellow, ROPE Project Lead added:

“This project presents a unique and exciting opportunity to look at the effects of habitat enhancement resulting from offshore aquaculture development. Very little is known about the ecological consequences of offshore aquaculture, despite calls for a move towards offshore development and a recent emphasis on Blue Growth in the UK. Aquaculture is listed as one of the key development sectors and this study will support the evaluation of offshore aquaculture in sustainable management of the ocean.”

With growing interest in offshore aquaculture and increasing desire for greater protection it will be crucial to determine if co-locating shellfish aquaculture in close proximity to MPAs have synergistic benefits for replenishing fished populations and supporting sustainable fisheries? Answers to this bigger question will have important implications in future conservation policy, marine spatial planning and the blue economy.