Research commissioned by the Scottish Shellfish Marketing Group (SSMG), in collaboration with the University of Edinburgh, confirmed that Scottish farmed mussels and oysters deliver by far the lowest Global Warming Potential (GWP) among all major farmed protein sources in the UK — including salmon.

The comprehensive Life Cycle Assessment (LCA), spanning from "farm to processor gate," evaluated the greenhouse gas emissions of shellfish production and compared them to other farmed proteins. The results show:

• Mussels and oysters generate significantly lower GWP per kilogram of edible protein than farmed salmon, chicken, pork, and beef.

  
  

• Oyster & mussel farming also “breathe life into the sea,” offering dual environmental benefits as they filter micronutrients from the water.

The Marine Stewardship Council (MSC) has certified Scottish mussel production businesses for over 14 years. “More recently two farms in Scotland have been award Aquaculture Stewardship Council (ASC) accreditation for their oyster cultivation, independent proof that they are one of the very lowest impact farmed proteins available,” said Nick Lake CEO of the Association of Scottish Shellfish Growers (ASSG), “This sets a new benchmark for sustainable aquaculture.”

Why Scottish shellfish lead in low carbon farming:

• Zero feed requirement: Both mussels and oysters derive their nourishment naturally from sea phytoplankton and other micronutrients — no land-based feed or fertilisers.

  
  

• Low energy cultivation: Mussels are grown on ropes, oysters on intertidal trestles or baskets, using the tidal flows to bring a consistent source of nutrients for growth.

  
  

• Minimal processing emissions: The LCA highlights efficiency in harvesting, processing, and distribution stages.

Production is increasing across Scotland — a record 11,690 tonnes of mussels were harvested in 2024, a 13% rise over the previous year, while 2.4 million Rock oysters were produced.

This reinforces Scottish shellfish's position as the UK’s greenest farmed protein. It comes as a timely boost to Scotland’s seafood sector, supporting both environmental and economic goals.

The new ‘Eat Scottish Shellfish’ campaign launched last year, is aiming to encouraging retailers, chefs, and consumers to choose Scottish mussels and oysters not only for their exquisite taste but for robust, science based environmental credentials.