The UK’s first large-scale offshore mussel farm, located in Lyme Bay off South Devon, is helping shellfish reefs return to the seabed for the first time in up to 150 years, according to a new study. Established in 2013, the farm’s mussel lines have transformed the seabed from muddy sediment into reefs, benefitting commercial fish species and the ecosystem.

Researchers from the University of Plymouth have monitored the farm’s environmental impact for a decade. Dr. Emma Sheehan, Associate Professor in Marine Conservation, said, “When we first started to monitor the mussel farm in 2013, we hoped to find evidence of its potential to restore the health of the seabed. That is something we have shown consistently.” 

The study also revealed that similar shell beds existed in the area in the 19th century, based on a historic map from 1871 describing “rich shell beds” across the seabed. Scientists believe these beds, likely oyster or mussel reefs, were destroyed by bottom-towed fishing gear during the 20th century.

Photo: University of Plymouth

With the designation of the Lyme Bay Marine Protected Area (MPA) and the mussel farm situated above these historic shell beds, the region is seeing the restoration of shellfish reefs. The study, published in Science of the Total Environment, found that commercially important species like European lobsters are using the mussel farm as a refuge and feeding ground, with some remaining in the area for up to 283 days.

John Holmyard, Managing Director at Offshore Shellfish Ltd, said, “These findings show that an area of flat, muddy and degraded seabed can be restored into a productive, biodiverse habitat.” The farm is creating a similar effect to the protection of a rocky reef, providing benefits to surrounding fisheries. 

Read the full research article here.