Nine ways to produce more sustainable and affordable blue food - Part 3

8. Post-harvest processing and distribution

Aquatic foods vary widely in terms of edible yields, nutritional content, processing techniques, distribution, consumption, and food loss and waste. These factors vary widely with geographical and cultural context and strongly influence environmental performance. Alongside species selection, increasing edible yields and reducing food loss and waste are arguably the most efficient short-term interventions for improving the environmental performance of aquatic foods, as less needs to be produced in the first place. Overall, edible yields and what actually is being eaten can range from 10% for some bivalves to 100% for some small-sized fish and sea cucumbers.

The FAO (2011) estimates that 35% of all seafood is lost or wasted worldwide. While this estimate might be excessive, it has been suggested that in North America almost half of all edible seafood supply is discarded, primarily as food waste at the consumer stage. In Africa and Asia most discards are at the production stage or during processing and distribution, often with accompanying losses in nutritional quality.

 There is, however, an ongoing shift in low-income countries from subsistence production toward sourcing food from markets, and from home cooking to consumption of processed food and food eaten away from home, which implies longer supply chains that will influence utilization rates. Other reduction strategies for food loss and waste range from simple changes in practices, such as handling fish with care, avoiding contamination, using insect nets, improved drying techniques, better hygiene and public awareness, to refrigeration, improved infrastructure, clean water, improved packaging material, food safety legislation, and promotion of value-added products from low-value fish species.

Large-scale processing can improve possibilities for utilizing by-products for food, feed, or industrial uses. It has been estimated that better by-product utilization could increase food output from the Scottish salmon industry by 60% and could satisfy 65% of China's fishmeal demand.

By utilizing these resources, larger volumes could be produced with a similar overall environmental footprint, resulting in lower impacts per volume and better resource efficiency. Product forms determine amounts being wasted and lost, but can also considerably influence the market demand for, and environmental impacts of, seafood production. Long transport of live animals should be avoided, as it can more than double environmental impacts through energy used for distribution and cooling, especially if the animals are airfreighted.

Canning minimizes food waste and allows for slower modes of transport, but packaging and using oil for preservation may instead become environmental hotspots. Freezing is an efficient way of preserving food, but needs to be supported by efficient cooling methods as it otherwise might result in high energy use and the release of refrigerants. Ultimately, sun-drying, where possible, may be promoted as one of the most sustainable forms of preservation if loss/waste levels are kept low.

9. Financial tools

Many smallholder farmers cannot benefit from farm improvements, such as quality feed, seed, and disease diagnostics, due to limited access to credit. Neither are they likely to explore new farming methods, as they are vulnerable to risk. Enabling insurance providers and cooperatives could here play important roles in alleviating risk and gaining access to credit and markets among smallholder aquaculture farmers. Cooperatives may also improve the utilization of infrastructure, and thereby reduce overall environmental impacts.

Access to shared infrastructure, improved fry, cheaper feeds, and markets could be improved by upscaling production of a limited selection of species.

This tendency is present in aquaculture, similar to what has been seen in terrestrial livestock farming. However, scaling may also counteract the resilience and resource efficiency that diversity can bring to aquaculture.

Striking a balance between industrial and smallholder farming, and implementing interventions appropriately, is key here for accommodating benefits associated with diversity and economies of scale simultaneously.

Discussion

Aquaculture holds potential to improve the sustainability of animal-based foods and the overall food system, but additional efforts are urgently needed for it to reach its full potential. In agriculture, much research has focused on “closing the yield gap” (the mismatch between possible and realized maximum yields) and, more recently, on “sustainable intensification,” which refers to achieving higher yields while using fewer resources per production output.

These strategies are aimed at increasing food supply while reducing food production's relative environmental footprint.

In aquaculture, it is harder to establish maximum potential yields per area, as there are more trade-offs with life-cycle inputs, such as feed, water, and energy. Nonetheless, we argue that a huge performance gap persists for most accessible commodity and accessible niche seafood, including carps, tilapia, and milkfish. Much of this gap could be closed through simple interventions that are readily available, including better management practices, better hygiene and biosecurity, and post-harvest handling and processing.

In some cases, simple improvements have not been realized yet due to limited know-how among aquaculture farmers and other supply chain actors. Financial barriers and perceived risks are also important constraints. This scenario suggests scope for gains through efforts to strengthen and expand producer groups, extension services, training, and financial support. Other interventions would require longer-term resource commitments. These include upgrading farm infrastructure, establishing genetic improvement programs, and development of vaccines and novel feeds. A third group of interventions could provide incentives for farmers and industry to adopt more environmentally sustainable practices. These include spatial planning, stricter environmental regulations, and financial incentives encouraging better production practices. This last set of interventions is central for going beyond business as usual, as profitability is the most fundamental driver of the industry, which is in turn mediated by price premiums or cost reductions.

Even though many aquaculture systems perform environmentally favorably compared with most terrestrial animal production systems, their continued expansion will lead to additional stress on resource systems and planetary health.

In response, innovations with plant-based and in vitro-cultured aquatic food alternatives are accelerating quickly. The extent to which these technologies will outperform traditional farming, both environmentally and economically, is uncertain, and at present such alternative products mainly target replacements for luxury aquatic foods and consumers in high-income countries. The bulk of accessible and affordable aquatic foods will continue to be produced by small- and medium-scale farmers that struggle with limited financial means and capacity to optimize the environmental performance of their production independently. Strengthening R&D together with widespread training programs and extension services for these farmers could offer a more efficient way forward for making aquatic foods more accessible.

The aquaculture sector has been slow to deploy financial tools (e.g., insurance, forward contracts, and futures markets) that can help farmers manage economic risks, often due to uncertainty about the risks themselves and volatility in production.

The improvements listed in the sections above can help make the business case for the use of financial tools by optimizing and stabilizing production and, in doing so, de-risk external investments in farm and sectoral improvements.

Adding all these together, we can expect that global aquaculture yields could increase substantially over the next decade, while reducing the environmental impact per unit of output. Improving production systems, management practices, and genetic strains could reduce FCR and environmental impacts by roughly 25%.

Achieving these gains will require access to tailored commercial feed for the most important species (e.g., carps) and novel feed ingredients. Market access and consumer acceptance will also be essential for promoting fish relying on lower-trophic level diets. Improvements in post-harvest processing and distribution could help improve utilization and profitability, while reducing food waste and loss with overall positive effects on global resource use.

Promoting value-added products would also encourage centralized processing and better utilization of by-products.

LCA, our most commonly used environmental framework for benchmarking food production systems, remains insufficient with respect to the availability of methods for assessing all sustainability aspects relevant to the growth of aquatic foods.

Some supplemental methodologies have been proposed to capture aquatic impacts in LCAs, including biotic resource use and seafloor disturbance.

However, the net gains in human food resources are rarely addressed.

In aquaculture, and particularly for luxury commodity and niche species, fish and crops that potentially could be consumed by humans are also used as ingredients in aquafeed. Agricultural feed substitutes may, moreover, compromise the nutritional quality of aquatic products and aggravate impacts related to biodiversity loss, global warming, biogeochemical flows, and freshwater availability.

This applies to fed aquaculture systems in freshwater and marine environments alike, as feed often is responsible for >90% of farmed finfish environmental life-cycle impacts.

In these systems, FCR remains an important indicator of environmental performance. Meanwhile, further horizontal expansion of coastal and inland pond aquaculture risks increasing competition for freshwater resources, deforestation, and methane emissions, making a strong case for responsible intensification of already existing systems, with increased reliance on feed as a consequence.

Thus, just like for biofuels, the second and third generations of aquafeed need to focus on resources that do not compete with food for human consumption or for available land.

Conclusions

Aquaculture holds great potential to contribute to more sustainable diets, but many farming systems still suffer from large performance gaps and unsustainable practices. Many of the most impactful interventions for resolving these challenges are already available and would need to target accessible aquatic food species, a high proportion of which are produced on small- and medium-scale farms. These interventions require a mix of both short- and long-term actions, but many could be implemented at low monetary costs. However, tailoring the most efficient interventions to the diverse set of farming systems and incentivizing their implementation remains the greatest challenge and requires government support.

We contend that financial incentives and regulatory efforts, alongside investment in genetics, feed, and farm management, including better record keeping and data management by individual farmers, are needed to boost aquaculture production, improve resource-use efficiency, and reduce environmental impacts. Meanwhile, luxury aquatic foods from offshore systems and RASs have the potential to reduce environmental impacts on the scale of the global food system if they replace red meat in diets, but their contribution to feeding the global population will be limited.

Sustainable intensification of existing systems for increasing accessibility of aquatic foods, based on scaling of proven but infrequently adopted interventions, could contribute substantially to realizing sustainability goals in aquaculture. However, these systems and improvements also need to be better benchmarked using LCA and complementary frameworks, to identify overall potential sustainability gains. Aquatic foods alone cannot ensure future food security but, if developed thoughtfully, they can play a greater role in alleviating the current food system's environmental pressures on the planet.