Given the current predictions, climate change is unlikely to have a significant effect on Scottish mariculture over the next decade. However, within the next 50 years or more, the forecast changes are likely to result in noticeable effects. Rising average water temperatures will result in faster growth rates for some species (e.g. Atlantic salmon, mussels and oysters) but prolonged periods of warmer summer temperatures may cause thermal stress, particularly for cold water species (e.g. cod and Atlantic halibut) and intertidal shellfish (oysters). However, warmer waters may provide opportunities to culture new species, or species that are currently economically marginal in UK waters (e.g. sea bass, bream, abalone).

Diseases of cultured fish and shellfish including bacterial, viral, parasitic and fungal diseases, will be affected by a changing thermal regime, but in a largely unpredictable manner. However, under conditions of thermal stress, cultured species are likely to be more susceptible to disease and warmer conditions may allow the establishment of exotic diseases, while diseases such as cold water vibriosis, may become much rarer. Sea lice are likely to remain a problem in salmon culture and rising temperatures will extend their season and may increase infective pressure, requiring more treatments. Increased storminess (higher frequency of strong wind speeds) predicted for certain seasons in some regions will increase the risk of escapes through equipment failure and may necessitate site relocation or changes to equipment design.

The forecast warmer waters with calmer, drier summer months will have an effect on planktonic communities, although this will be difficult to predict in detail. There may be an increase in the frequency of harmful algal and jellyfish blooms, potentially causing more fish kills and closures of shellfish harvesting areas, but the forecast reduction in summer precipitation may benefit classification of shellfish growing areas. Increased temperatures and more abundant plankton could also enhance early spawning success and spat fall of cultured shellfish species, to the benefit of the shellfish industry.

What is already happening: Low

What could happen: Low

The UKCP09 predictions are the first attempt at regional-scale assessment of changes in the marine climate over the next century. There is broad confidence in the ability of the model to predict changes over the open shelf seas, though with some local uncertainties close to the shelf edge and in regions influenced by estuaries. The lack of confidence in the results arise from (1) this is the first and only prediction available, and (2) predictions particularly of the strength of stratification are determined by changes in regional meteorology, which is a challenging aspect of future climate projections.

The top priority knowledge gaps that need to be addressed in the short term to provide better advice to be given to policy makers are:

1. Socio-economic impact analysis of the predicted effects.
2. Impacts of climate change on the environmental impacts of aquaculture - e.g. assimilative capacity of receiving water bodies.
3. Update of epidemiological risk assessments on aquaculture pathogens to account for climate change factors.

To the author's knowledge there has been no formal socio-economic impact assessment in the UK of impacts of climate change on this aspect of Productive Seas.

Gubbins, M., I Bricknell, and M. Service (2010) Aquaculture in MCCIP Annual Report Card 2010-11, MCCIP Science Review, 12pp. www.mccip.org.uk/arc