Impacts of climate change on aquaculture
Matt Gubbins, Ian Bricknell and Matt Service
Gubbins, M., Bricknell, I. and Service, M. (2013) Impacts of climate change on aquaculture. MCCIP Science Review 2013, 318-327, doi:10.14465/2013.arc33.318-327
Download full report:
There is little existing evidence of impacts on aquaculture that can be attributed to climate change. Several effects have been observed that could be related to a changing climate such as increased shellfish contamination, harmful plankton events and the establishment of non-native species, but it is not clear that a changing ocean climate is responsible for these effects. 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. Sea-level rise may reduce coastal habitat suitable for bivalve cultivation in the south of the region (where Scottish mariculture is undertaken). 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.
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, making a move to offshore finfish culture more difficult.
Ocean acidifaction may have detrimental effects on mollusc spat-fall, making natural seeding of mollusc farms less efficient. Rising water temperatures may exacerbate the establishment of invasive species to higher latitudes potentially bringing increased costs to deal with fouling organisms or harm to stock.
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.