As our planet's oceans become increasingly vulnerable to the impacts of global warming, sustainable aquaculture is proposed as a key avenue to securing the future health of our marine ecosystems.
According to the most recent Summary for Policymakers by the Intergovernmental Panel for Climate Change (IPCC), "It is virtually certain that the global upper ocean (0–700 m) has warmed since the 1970s and extremely likely that human influence is the main driver." The impact of this global heating is already taking effect upon our oceans. A complimentary 2018 report warned that the migration of many species to higher latitudes would diminish coastal resources along with a projected decrease in annual marine catch of 1.5 million tons at the current rate of global warming.
In a plight to evade this bleak future, sustainable aquaculture is listed by the IPCC as a feasible adaption strategy. This message has already resonated across the globe, with increased funding and support directed towards enhanced aquaculture sustainability projects, including by the European Institute of Innovation and Technology (EIT):
This sector can make an important contribution to the fight against climate change, the reduction of pollution and the protection of ecosystems…it can also be a part of a more circular management of resources. Hence a strategic and long-term approach to the sustainable growth of EU aquaculture is therefore more relevant today more than ever.
European Institute of Innovation and Technology
How can Sustainable Aquaculture Combat CO2 Emissions?
Although the marine industry is vulnerable to the effects of climate change, it is has become apparent that aquaculture has the most significant potential to achieve a sustainable food chain compared to other forms of livestock.
The table below presents the findings of Marine Harvest with respect to the environmental factors associated with different forms of meat production. It is evident that salmon has the potential to produce greater quantities of meat for both lower resource requirements and contributory CO2 emissions.
Environmental factors associated with different forms of livestock according to Marine Harvest's 2017 report on the salmon industry. Table Credit: Salmon Farming Industry Handbook 2017/Marine Harvest
Further to this, in terms of efficient use of spatial resources, water-based aquaculture enables greater land use for harvesting vital crops and the restoration of natural habitats, increasing the productivity of the food industry and aiding natural carbon dioxide removal.
Yet, it is not just land-based ecosystems capable of controlling the critical carbon cycle. The Global Aquaculture Alliance reports that some bodies of water can store five times more carbon than rainforests, aided by the cultivation of aquatic plants, mollusks, and seaweed. In fact, the farming of mussels and oysters allows the growth of kelp, a type of seaweed that creates a carbon sink effect.
Crucially, the migration towards aquaculture as a prime nutritional resource must be entwined with the necessity to preserve existing marine ecosystems and promote the farming of multitrophic species. Not only will this help to diminish the anthropogenic emissions reported by the IPCC as being the predominant cause of global warming, but in turn will prevent the effects of warming on marine environments, protecting the future aquaculture industry.
Current Industry Barriers for Sustainable Aquaculture
Despite this potential, significant unsustainable practices are still present within the aquaculture industry, aggravating further the degradation of our ecosystems.
In 2018, water-based livestock consumed 20 million tons of wild fish-sourced feed. Considering this equated to almost one-fifth of global wild fish capture, of which a high proportion are juvenile, it is clear this cannot continue without endangering the future population of such species. Add the fossil fuel consumption alongside emissions associated with the large fishing boats traveling to capture this feed, and the concept of sustainable aquaculture is all but forgotten.
The latter is also a key consideration for the International seafood trade. It has become a common expectation for supermarkets to have a constant stock of foreign delicacies instead of local produce, leading to continuous traffic of carbon-heavy imports. This presents the challenge of both transitioning the shipping industry to alternative fuels and challenging modern consumer culture.
Image Credit: Attasit saentep/Shutterstock.com
Certain industrial practices must also be challenged. Gaps in the regulations surrounding open pen farming have ensured the release of organic waste into our oceans, leading to harmful algae blooms and the spread of disease. Meanwhile, the controversial conversion of mangroves for shrimp farming still remains in certain parts of the world, hindering the essential biodiversity of these habitats.
Addressing Aquaculture Challenges
The EIT's food arm has championed seven "sustainable aquaculture stars of the future" which it believes will address the acknowledged industry challenges and unlock the potential of a sustainable aquaculture future.
Amongst these winning projects, including efforts to reduce disease, develop a circular form of tuna farming, and facilitate a secure food chain, is the Swedish company Cewatech. This biotech firm is cultivating a novel, high-protein salmon feed produced from mushroom biomass. The feed will be a direct substitute for the fishmeal and soy-based feeds, battling the current unsustainable wild farming practices while also utilizing the unique immune-boosting mushroom properties to combat common salmon farming diseases. The EIT is now providing Cewatech support in bringing its patented product to commercial readiness.
On a broader scale, increasing pressure is being put on other feed companies and fisheries to operate at higher environmental standards. To achieve this, a simple yet canny tool is being employed: the power of consumer demand. Resources like Seafood Watch, the Marine Stewardship Council, and the Seafood Carbon Emissions Tool are being promoted as readily available information to assess the climate impacts and animal well fair associated with food choices. Increasing this awareness means a growing push from consumers for the fishing industry to meet higher sustainability standards.
The Future of Sustainable Aquaculture
With the clear potential for sustainable aquaculture as a climate change adaptation avenue and awareness of the current limitations increasing, aquaculture is now the fastest-growing food-production technology.
To continue this rate of growth in a positive direction, Lorenzo Juarez presents his recommendations within the 2020 Journal of the World Aquaculture Society:
Four areas of focus that should effectively coalescence in order for the goal of sustainable aquaculture to be realized are the preservation of intact habitat, efficient use of natural resources, traceability, and transparency.
Lorenzo Juarez, Chief Executive Officer, Sea Products Development
With increasing accountability and the development of alternative feed in progress, reliance on fossil fuels remains the prime barrier to an emission-free chain. Until this technology can be advanced, cage farming and mollusk culture are touted as the most efficient, habitat-preserving, low emission options.
Both the 2018 and 2021 IPCC summaries have highlighted the race for the industry to implement these adaptations before the imminent effects of climate change seal the fate of marine life.
Industrial Response to Climate Change
This article is a part of the IPCC Editorial Series: Industrial Response to Climate Change, a collection of content exploring how different sectors are responding to issues highlighted within the IPCC 2018 and 2021 reports. Here, Cleantech showcases the research institutions, industrial organizations, and innovative technologies driving adaptive solutions to mitigate climate change.
References and Further Reading
IPCC. (2018) Summary for Policymakers. Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. Available at: https://www.ipcc.ch/site/assets/uploads/sites/2/2019/05/SR15_SPM_version_report_LR.pdf
IPCC. (2021) Summary for Policymakers. Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate. Available at: https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf
Boyd, C. D'Abramo, L. Glencross, B. (2020) Achieving sustainable aquaculture: Historical and current perspectives and future needs and challenges. Journal of the World Aquaculture Society, Vol 51, Issue 8, pp 578-633. Available at: https://doi.org/10.1111/jwas.12714
Cewatech.se. (2021) About Cewatech – Welcome to Cewatech. [online] Available at: http://www.cewatech.se/om-cewatech/
Global Aquaculture Alliance. (2020) How Farmed Seafood Can Support Climate Action. [online] Global Aquaculture Alliance. Available at: https://www.aquaculturealliance.org/blog/farmed-seafood-climate-action/
MacLeod, M.J., Hasan, M.R., Robb, D.H.F. et al. (2020) Quantifying greenhouse gas emissions from global aquaculture. Scientific Reports, Vol 10. Available at: https://doi.org/10.1038/s41598-020-68231-8
Marine Harvest. (2017) Salmon Farming Industry Handbook. Available at: http://hugin.info/209/R/2103281/797821.pdf
Morrison, O. (2021) Meet the 7 Sustainable Aquaculture Stars of the Future. [online] Food Navigator. Available at: https://www.foodnavigator.com/Article/2021/06/21/Meet-the-7-sustainable-aquaculture-stars-of-the-future
Narayanan, R. (2019) The Right Seafood Choices Hep Fight Climate Change. [online] Yale Climate Connections. Available at: https://yaleclimateconnections.org/2019/05/the-right-seafood-choices-help-fight-climate-change/
The Ocean Foundation. (2021) Sustainable Aquaculture. [onlne] The Ocean Foundation. Available at: https://oceanfdn.org/projects/sustainable-aquaculture/