SAMS news room

Shellfish farmers face climate change ‘tipping point’

Climate change and ocean acidification is affecting shellfish such as mussels
Climate change and ocean acidification is affecting shellfish such as mussels

The global shellfish aquaculture industry may have just 40 years to adapt to the changing climate as global warming, ocean acidification and extreme weather events place an increasing risk to its viability.

That is the conclusion of researchers from the Scottish Association for Marine Science (SAMS) in Oban, Scotland, who modelled the effect that climate change and ocean acidification would have on the industry in 117 countries worldwide.

Ocean acidification occurs as increasing amounts of carbon dioxide dissolve into our seas. This has an effect for many marine creatures, especially commercially-important shellfish like mussels, oysters and scallops.

Examining each country’s exposure to environmental changes, and the ability of each aquaculture sector to adapt, the scientists’ mathematical model showed 2060 would mark a ‘tipping point’ in the viability of the current global shellfish industry.

Their findings, Vulnerability of Shellfish Aquaculture to climate-change and ocean acidification (, are published in Ecology and Evolution and recommend that shellfish aquaculture should consider diversifying and/or growing species more tolerant of changing conditions.

Dr Tom Wilding of SAMS, a benthic ecologist and co-author on the report, said: “Bivalve shellfish will be at particular risk from climate change and ocean acidification, as they are calcifying organisms that will have to work harder to form shells as the oceans become more acidic.

“We believe that shellfish farmers will have to adapt by considering alternative species, selective breeding or by moving their operations to cooler waters.

“Depending on where you are in the world, the main threat could come from a lack of governmental support, a reliance on species that are not well adapted to increased temperatures and acidities, or projected declines in plankton which is the main food source of shellfish.”

The model used in the study was based on the Representative Concentration Pathway (RCP) 8.5 scenario, in which the global average temperature rises 3.7 degrees Celsius by 2100, and drew on shellfish production figures data from the United Nations’ Food and Agriculture Organization (FAO). The model did not include the potential increased threat of disease in warming waters.

Although 2060 may be a ‘tipping point’ for the industry, the impact of climate change will see rapid declines in shellfish production as soon as the coming decades in some nations.

Co-author Phoebe Stewart-Sinclair said: “Vulnerability in developing countries resulted, primarily, from the cultivation of species that have a narrow habitat tolerance and could be affected by a slight rise in temperature, whilst the risk to some European nations (France, Ireland, Italy, Portugal and Spain) was attributable to the relatively high economic value of the shellfish production sector at present. 

“The ability of the industry to adapt was low in developing countries, primarily due to governance issues, while in some developed countries (Denmark, Germany, Iceland, Netherlands, Sweden, and the United Kingdom) it was linked to limited species diversity.”