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What is already happening?
  • In the UK, there have been no major changes to the types or locations of species farmed due to climate change.    
  • At salmon farms, a strong link between milder winter temperatures, disease and increased fish mortality has been identified.
  • In Scotland, some shellfish areas have experienced poor spat settlement and mortality, but the link to climate change is not fully established.

Low evidence, low consensus

There have been no major shifts in species farmed or evidence for climate-driven changes in production. Any climate effects are low compared to changes associated with economic and technological developments in the industry. There is some evidence for temperature-related effects on salmon mortality, emergence of amoebic gill disease, Harmful Algal Blooms, jellyfish, invasive species, and shellfish infections, although there are no trends for storm damage.
Overall, confidence remains ‘low’ as definitive links to climate change, as opposed to seasonality, are lacking.

What could happen in the future?
  • Temperatures are expected to remain suitable for salmon growth until the end of the century, when aquaculture in Northern Ireland and the southwest of Scotland may experience seasonal declines due to warming.

  • Ocean acidification may reduce shellfish spat settlement, although it is unlikely to affect finfish farming.  

  • Warming conditions will lead to a rise in outbreaks including sea lice, fish diseases and shellfish pathogens, with subsequent increased mortality. 

  • The risk of mortality due to more frequent and intense heatwave events will increase in the future, highlighting the need for adaptive management.  

  • Offshore facilities may be more exposed to structural damage due to potential changes in storm events, with an increased risk of farmed species escaping.  


Medium evidence, low consensus

Salmon growth rates are likely to increase but UK waters are expected to remain suboptimal for new species such as sea bass. Existing impacts from gill disease, and effects of sea lice are likely to continue. Similarly, shellfish aquaculture may benefit from increased growth rates in warmer waters, although diseases may become more prevalent and ocean acidification may reduce mussel smolt settlement. New species of shellfish such as abalone might be farmed in southern UK waters. Future impacts from HABs and jellyfish could increase in warmer seas but there is low confidence as blooms depend on complex ecosystem behaviour.
Overall, there is moderate confidence in impacts from climate change. Disease impacts will be negative, but some negative impacts may be mitigated by adaptation strategies and technological fixes, particularly in the salmon sector which has a high level of innovation, and growth rates are likely to increase. So net impacts of climate change may be low.

Key Challenges and Emerging Issues
  • Understanding synergies between different pathogens and environmental drivers in fish health response to climate change.

  • Understanding the synergistic effects of climate change and ocean acidification (and the effect of fluctuating, compared to continuous, exposure to these impacts) on settlement, growth and shellfish aquaculture species. 

  • Identifying the potential impacts of climate change on environmental conditions at aquaculture sites, such as the assimilative capacity of receiving water bodies, including those offshore.

  • Identifying climate change impacts favour the establishment and spread of invasive non-native species and their potential impacts on the sector. 

Image credit: SSPO