Impacts of Climate Change on Aquaculture

Seagrass Ocean Rescue. Credit: Lewis M Jefferies

Aquaculture, the farming of fish, shellfish and aquatic plants, is one of the fastest growing sectors of global food production. In the UK, it plays a key role in rural economies and food security, particularly through salmon farming, mussel cultivation and freshwater species.

However, aquaculture is deeply dependent on stable environmental conditions. As climate change alters water temperature, acidity and availability, the viability of this sector is increasingly under threat. Understanding the risks and what can be done to adapt is essential for farmers, policymakers and communities alike.

How Aquaculture Is Vulnerable to Climate Change

Aquaculture systems, whether in freshwater ponds, estuaries or offshore cages, rely on precise water conditions. Small changes in temperature, salinity or pH can cause major disruptions to species health, reproduction and survival.

Climate change introduces variability and extremes that undermine the predictability aquaculture depends on. From algal blooms to altered breeding cycles, the pressures are mounting with economic consequences as well as ecological ones.

Environmental Impacts on Aquaculture Systems

Rising Water Temperatures

Warmer water affects fish metabolism, leading to changes in growth rates, feed needs and susceptibility to disease. In some areas, rising temperatures may make traditional species unviable.

Temperature increases also fuel harmful algal blooms, which reduce oxygen levels and can release toxins. These blooms disrupt aquaculture operations and increase the risk of mass mortality events.

Ocean Acidification

As oceans absorb more carbon dioxide, their pH drops, a process known as ocean acidification. This has serious effects on shell forming organisms such as oysters, mussels and scallops.

Acidified conditions reduce larval survival and weaken shells, threatening the long term viability of shellfish farming. Coral based habitats, which support many coastal fisheries, are also at risk.

Sea Level Rise and Storm Surges

Coastal aquaculture infrastructure is vulnerable to sea level rise, flooding and storm damage. These events can contaminate sites, damage cages or gear, and increase the cost of insurance and maintenance.

For near shore systems, saltwater intrusion and sediment movement may reduce water quality or alter key habitats.

Changes in Rainfall and Salinity

Inland and estuarine aquaculture depends on stable freshwater flows and salinity gradients. Changes in rainfall patterns can reduce water availability, alter nutrient balances and increase the frequency of drought or flood.

These shifts affect both the physical environment and the physiology of farmed species, particularly in more sensitive pond based systems.

Disease and Parasite Pressure

Warmer, more stressed aquatic environments create ideal conditions for disease outbreaks and parasite spread. In the UK salmon industry, sea lice have become an increasing concern.

High stocking densities and rising temperatures make fish more vulnerable to infections, which can spread rapidly and cause major losses. Managing these risks requires careful monitoring, as well as investment in resilient farming systems.

Implications for Food Security and Livelihoods

Climate impacts on aquaculture can reduce productivity and increase costs, making seafood less accessible and affordable. This threatens food security, especially in regions where fish is a primary protein source.

In the UK, aquaculture also supports rural jobs and coastal economies. Losses in this sector affect not only food supply but also livelihoods, from fish farm workers to processors and logistics providers.

Adapting Aquaculture to Climate Change

Despite the challenges, there are promising ways to adapt aquaculture to a changing climate. These approaches focus on building resilience, increasing flexibility and using nature based solutions.

Farm Relocation and System Redesign

In some cases, farms may need to move to cooler waters or more stable areas. Others are investing in closed or land based systems, which offer more control over environmental conditions.

These systems reduce exposure to parasites and weather extremes, though they require higher capital and energy inputs.

Species Diversification and Breeding

Farmers are exploring more climate resilient species, including those better suited to warmer or variable conditions. Selective breeding programmes can also improve tolerance to stress, disease and acidified water.

This diversification spreads risk and may help ensure consistent production as conditions continue to change.

Integrated Systems and Nature Based Solutions

Some producers are combining species to create more balanced ecosystems. Shellfish and seaweed, for example, help filter water and absorb excess nutrients.

Integration with wetlands or paludiculture systems can further enhance resilience. These approaches mimic natural processes and offer co benefits for biodiversity and carbon storage. You can read more in our article on paludiculture.

Climate Policy and Aquaculture’s Role

Aquaculture is increasingly being considered in climate policy, both as a vulnerable sector and as part of a sustainable food system. To reduce its footprint and improve resilience, the industry will need to adopt lower impact practices, improve monitoring and support innovation.

Policymakers can help by providing incentives for adaptation, funding research and supporting skills development in sustainable aquaculture.

Aquaculture FAQs

How does climate change affect aquaculture systems?

Climate change affects aquaculture by altering water temperature, acidity, salinity and availability. These shifts impact species health, productivity and survival.

What are the environmental and economic risks for fish and shellfish farming?

Environmental risks include disease outbreaks, harmful algal blooms and infrastructure damage. Economic impacts include reduced yields, higher costs and threats to coastal livelihoods.

What solutions exist to adapt aquaculture to a changing climate?

Solutions include relocating farms, diversifying species, redesigning systems and using integrated approaches such as seaweed and shellfish farming.

How does aquaculture fit into climate friendly food systems?

Sustainable aquaculture can provide low emission protein and support local economies. Climate smart practices and policy support are essential for its future.

Aquaculture will continue to play a vital role in UK food systems, but only if it adapts. The climate is changing, and so too must our approach to farming the sea.

Sources:

• https://www.nhm.ac.uk/discover/the-problem-of-sea-lice-in-salmon-farms.html
• https://www.wwf.org.uk/what-we-do/aquaculture

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