Blue food systems are crucial for meeting global social and environmental goals. Both small-scale marine fisheries (SSFs) and aquaculture contribute to these goals, with SSFs supporting hundreds of millions of people and aquaculture currently expanding in the marine environment. Here we examine the interactions between SSFs and aquaculture, and the possible combined benefits and trade-offs of these interactions, along three pathways: (1) resource access and rights allocation; (2) markets and supply chains; and (3) exposure to and management of risks. Analysis of 46 diverse case studies showcase positive and negative interaction outcomes, often through competition for space or in the marketplace, which are context-dependent and determined by multiple factors, as further corroborated by qualitative modeling. Results of our mixed methods approach underscore the need to anticipate and manage interactions between SSFs and aquaculture deliberately to avoid negative socio-economic and environmental outcomes, promote synergies to enhance food production and other benefits, and ensure equitable benefit distribution.
Aquatic, or ‘blue’, foods captured or cultured in marine and freshwater ecosystems are important sources of food and nutrition globally1,2,3. Over 3 billion people receive at least 20% of their animal protein from aquatic foods4, and micronutrients found in aquatic foods are crucial for addressing nutrient deficiencies worldwide5,6,7. Aquatic food also supports livelihoods for an estimated 800 million people globally2.
Demand for aquatic foods has increased despite the leveling-off of fisheries production since the 1990s4,8 and is projected to nearly double by 20509,10. While SSF catch is not well-documented, it is estimated to be at least 40% of global catch and two thirds of catch for human consumption4,11. SSFs exhibit extremely high diversity in their characteristics and circumstances, and vary greatly in their assets, diversification of products and activities, governance, and relation to markets12. While many SSFs face growing threats and are declining, there is great potential, and urgency, to support SSFs for social and environmental benefit12,13.
Aquaculture has grown rapidly in the past two decades, primarily driven by growth in freshwater aquaculture in China and other Asian countries14. The aquaculture industry is pushing for even faster growth, including in marine and brackish aquaculture, to fill the gap between fishery production and seafood demand and achieve food security and livelihood goals (e.g., the UN Sustainable Development Goals). As a result, many governments are promoting and subsidizing the development of aquaculture, both in fresh and marine waters15. Marine aquaculture expansion is expected to help meet the needs of a growing global population16, but see17 and offset many losses from SSFs due to climate change18. However, the development of the aquaculture sector has not occurred in a void. The current expansion of aquaculture in marine environments occurs mostly in nearshore waters, which are often already being used by many other sectors, including SSFs. In this paper, we focus on the interactions between marine aquaculture and SSFs.
Both capture fisheries and aquaculture will be necessary to help achieve ambitious global goals to end hunger and malnutrition, and to generate more livelihoods without adverse environmental or social impacts. Hence, there is an urgent need for guidance and best practices for how to promote benefits and reduce the likelihood of negative interactions between SSFs and aquaculture to optimize social, economic, and ecological performance of blue food systems that include both sectors. Here, we identify benefits and trade-offs between SSFs and aquaculture through a review and analysis of 46 case studies, across diverse systems, geographies, and conditions. We further explore these interactions through qualitative modeling. Results highlight high heterogeneity of interactions and outcomes, and the need for intentional coordination and management to maximize benefits and reduce negative interactions.
Hypothesized synergism and trade-offs between SSFs and aquaculture
While SSFs and aquaculture are often characterized as distinct elements of blue food systems, in reality, they exist along a spectrum19. Historically, and recently, small-scale fishing communities have developed aquaculture operations as an alternative or complement to wild capture fisheries20,21,22. For example, Hawaiian fishers prior to European colonization created and maintained fishponds to support local food security. More recently, the Tongan government began creating protected clam circles for broodstock in the late 1980s after several species were listed as endangered and one species went extinct within Tongan waters21.
By contrast, other aquaculture endeavors are developed by entities external to SSF communities, without directly accounting for impacts on fishing communities23,24. Moreover, aquaculture development can occur through a suite of regulations and processes that involve national or international companies, often without coordination between groups working in fishing and aquaculture research and innovation. For example, high start-up costs of Filipino milkfish aquaculture limit ownership of the installations, often to foreign owners, who are also the sole decision-makers in the operations. This lack of distributed decision-making power, along with a lack of regulation on over-stocking and feeding practices, and the privatization of previously public fishing waters, have resulted in the marginalization of many fishers as these types of farms expand25. Moreover, while in some cases producing the same products, fishing and farming may require fundamentally different investments, technology, and knowledge. Finally, aquaculture expansion is expected to contribute to food security and nutrition by enhancing and stabilizing the supply of aquatic foods, but unintended consequences have been documented. In Bangladesh, because of aquaculture expansion, fish consumption increased by 30% between 1991 and 2010, but iron and calcium intake from fish decreased over this period, reflecting the lower nutritional quality of the farmed species26. The implementation of aquaculture under different regulatory or immanent scenarios can result in varying success, in terms of achieving implementation goals27. This highlights the need for understanding the drivers of success within aquaculture, and its interactions with small-scale fisheries.
While aquaculture and fishing can both contribute to the goals of achieving food security, nutrition, employment, and livelihood opportunities, they can also compete in several ways28. They both make use of natural ecosystem processes and productivity, largely in nearshore waters. Aquatic foods from both sectors can enter the same markets. Moreover, fisheries and aquaculture may confer food security and livelihood benefits to different groups of people, due to differences in access and rights, distribution, pricing, consumer preference, or other factors. Therefore, aquaculture expansion in waters being used by SSFs could result in the production of less nutritious food, reduced livelihood support, and negative social, cultural, and ecological impacts16,25,29.
Based on a literature review and the authors’ experience in diverse blue food system contexts, we hypothesize that three main factors influence whether interactions between aquaculture and SSFs in coastal and marine settings are synergistic (i.e., taken together, the two sectors generate overall positive environmental, social or economic outcomes) or antagonistic (i.e., result in trade-offs and negative impacts of aquaculture on SSFs) (Fig. 1): 1) access to resources and allocation of rights; 2) the nature of interactions in markets and through supply chains; and 3) exposure to and management of risks from exogenous factors, e.g., disease, habitat degradation and climate change, including extreme events. We recognize that varying definitions exist for the terms we use throughout this article. As such, the definitions used here are included in the Supplementary Materials (Suppl. Table 1)…….