Supporting sustainable food systems with aquaculture

Aquaculture is at the forefront of supplying high-quality, nutritious protein for a growing population, with aquatic food seen as a key element of the COP 31 Agenda to develop resilient, adaptive and sustainable food systems.

For the first time in 2022, global aquaculture production moved beyond capture fisheries, according to the FAO. 

While it is one of the most efficient ways to produce animal protein, challenges include emerging diseases, nutrient pollution, antimicrobial use, economic inequalities, habitat destruction and competing resource use, especially from marine systems.

While expansion can be viewed as a success story, aquaculture, and particularly the intensive farming of carnivorous species, is at risk of exceeding the ecological boundaries which it was intended to benefit.

Meeting these challenges requires an integrated approach known as One Health, to balance the health of people, animals and ecosystems.

The food we feed to farmed fish accounts for at least three-quarters of the environmental footprint of aquaculture. 

A large focus to improve sustainability has been by reducing use of wild harvest marine fish meal (FM) and fish oil (FO). 

Formulated aquafeeds have changed rapidly and now include more than 40 plant ingredients, insect meals and rendered by-products from terrestrial and aquatic sources.

The forage fish dependency ratio (FFDR) is a modern holistic sustainability metric, which across all fed species now shows that 8kg of fish is produced from around 1kg of wild fish resources, according to the IFFO.

Marine ingredient use has been greatly improved over the last 20 years, with most species having reduced inclusions of marine FM and FO by five to 10-fold, including nearly four-fold reduction in FFDR for salmon (IFFO).

With the shift from marine to terrestrial ingredients in aquafeeds to support increased production, another paradox emerges where significant trade-offs in sustainability metrics must consider land and water use, carbon footprint and eutrophication.

The potential negative impacts of soy protein concentrates and rapeseed oil are a particular concern.

Novel ingredients can break this cycle, especially single cell ingredients from bacteria, microalgae, yeast and fungi, providing novel sustainable alternative sources of protein, oils, including long chain polyunsaturated oils, and functional molecules such as natural carotenoid pigments that colour salmon muscle.

The aquafeed industry exemplifies how aquaculture operates circularly, using by-products and waste streams, while developing new sustainable ingredients, producing diets with complementary beneficial ingredients. 

This allows iterative movement towards restorative approaches that balance ecosystem and human production system impacts.

Land-based or recirculated aquaculture systems are a new frontier that allow consistent, scalable and local production. 

By merging diverse technological innovations, these aim to provide enhanced fish health and welfare, with reduced environmental impacts.

Superior biosecurity prevents disease, largely eliminating chemical and antibiotic treatments and disease transmission to wild stocks and reducing risk of antimicrobial resistance.

Closed water systems enable waste recovery, providing nutrient recovery for fertilisers and bioenergy while protecting natural water systems.

Significant challenges remain, however, including infrastructure costs, energy demands, system reliability and competing water resource use, all contributing to economic viability.

The animal’s biology ultimately determines how it responds to disease and environmental challenges during production, and how efficiently it converts nutrients into growth. 

This requires fundamental science, aligned with industry and government, to translate discovery into accelerated breeding of resilient aquatic animals, and evidence to inform responsible policy and regulation that underpins sustainable aquaculture development.

My research, and that of others in the Royal (Dick) School of Veterinary Studies at the University, aims to do just that, harnessing the power of genomics to fast-track genetic improvements in aquaculture. 

This includes resolving regions of the genome responsible for disease resistance, while defining unique molecular signatures in fish immune tissues, the impacts of whole of life rearing conditions and production environments. 

Across diverse species from fish to shrimp and molluscs, these innovations enable a data-driven cycle of continuous improvement that deliver incremental gains in resilience, welfare and resource use efficiency, and unlock the next generation of innovation that benefits animal, environmental and human health alike. 

The health of farmed aquatic animals is intrinsically linked with the health of humans and the environment, a concept known as One Health. 

The human value of protein and lipids from seafood is unmatched, which when compared with other animal proteins provides the highest nutrient value and lowest carbon emissions.17

Additionally, replacing red meat with oily fish-like salmon has demonstrated benefits protecting the environment and raising human health standards. Safe, responsible and sustainable production means greater access to more nutritious, minimally processed foods.

Aquaculture has the potential to fundamentally change how and where seafood is produced and how it is consumed. 

For most countries, locally farmed or caught whole fish and shellfish can sustainably increase nutrient availability.

The aquaculture industry is circularity in practice – not simply recycling physical resources, but iteratively increasing knowledge, resources, genetic progress and biological efficiency to improve productivity, health and welfare.

Aquatic farming systems have great potential for further improvement and diversification, through the equitable supply of novel sustainable feeds to new genetically improved resilient aquatic animals, that deliver locally produced, nutrient-rich aquatic animal protein while enhancing local livelihoods and aquatic natural resources.

Realising this potential will benefit from One Health approaches that link the surveillance and governance of animal, human and environmental health.

Image credit: Karl Muscat via Unsplash.