As noted above, market-based interventions comprise a wide array of approaches focused on generating incentives along the supply chain that favor sustainability. In broad terms, market-based approaches can be grouped into three different categories: (1) governmental regulation (of markets and market actors); (2) voluntary private sector commitments; and (3) capacity building initiatives (Table 1). Regulatory approaches include a diverse set of policy levers that governments employ to influence markets and the various business actors engaged in the fisheries sector. In these approaches, sustainability is delineated via governmental legal instruments and policies that mandate fishers and businesses comply with requirements. These requirements may take three general forms: trade policies that restrict the flow of fisheries products across national boundaries, input controls that determine who can fish, when they can fish and how they may fish, and output controls that dictate the amount and type of catch - thus restricting the quantity, quality, composition, and timing of the flow of seafood products into market systems. Whereas harvesters and aquaculture farms have long been subject to policies that dictate operation and management of these production systems (e.g., licensing and permitting, gear/temporal/geographic restrictions, and import/export regulations) and supply chain actors are familiar with requirements on seafood handling (i.e., for food safety), governmental policies for regulating markets toward sustainability are relatively new. However, regulatory efforts to prevent overharvesting on coral reefs are increasing: Kiribati, the Philippines, Indonesia, Palau, and Tonga have restricted the commercial sale and/or export of numerous coral reef species, several Caribbean nations (Barbuda, Bermuda, Belize, Bonaire, Curacao, Turks and Caicos, Dominican Republic, Mexico, and Saint Vincent and the Grenadines) have banned or significantly restricted the fishing of ecologically important herbivorous reef fishes, and the harvesting of ornamental reef species has been restricted in Hawai‘i and several Pacific Island nations (Dee et al., 2014; Jackson et al., 2014; Birkeland, 2017; Republic of Palau, 2019). Governments can also provide incentives such as vessel buybacks in efforts to reduce fishing effort, although fisheries subsidies often distort markets and drive unsustainable practices (Clark et al., 2005; Schuhbauer and Sumaila, 2016).

Voluntary private sector commitments include an array of corporate social responsibility policies which private sector actors develop and institute into business practices (CEA, 2014; Kittinger et al., 2021). For voluntary approaches, sustainability is driven by voluntary commitments from buyers (e.g., grocery chains, hotels, and restaurants), processors, or sellers, with the intent of generating demand signals for sustainable seafood in the supply chain. Key examples include sourcing commitments and associated policy requirements, and requirements for traceability and transparency systems to ensure sustainability throughout the supply chain (Table 1). Among the most important elements of these approaches are the seafood certification and ratings systems, which have significant recognition among market actors (Certification and Ratings Collaboration, 2020). Certification and ratings systems are supported by their associated standards and verification systems and communicated to consumers and buyers via ecolabels and branding. Verification is often supported by catch documentation and traceability programs that include records of production and product movement throughout the chain of custody, with associated auditing and oversight platforms. Certification is often achieved via fishery improvement projects (collaborative initiatives that include stakeholders throughout a fishery’s supply chain and often involve support from government and environmental non-governmental organizations) that help to address sustainability and fishery data shortcomings (Conservation Alliance for Seafood Solutions, 2021). Certification and ratings systems have widespread adoption among businesses, particularly in developed countries (CEA, 2014; Roheim et al., 2018). Seafood ratings guides are also utilized by retailers including grocery and restaurant chains to meet their seafood sustainability commitments (Seafood Watch, 2020). Consumer education campaigns and programs are also often employed to elevate demand for sustainability in the marketplace and include regional sustainable seafood guides (initially geared toward consumers in North America, Europe, and Australia but expanding to consumers in Asia and several developing reef-adjacent nations) and supermarket sustainability rankings (Certification and Ratings Collaboration, 2020).

Voluntary private sector commitments were originally designed for commodity seafood (i.e., seafood from single-species industrialized fisheries or industrialized aquaculture sectors) and have been adopted primarily by large-scale seafood buyers in developed countries. In more developed nations, these schemes have resulted in greater interest in sustainability being transmitted throughout the supply chain, from food manufacturers, retailers, restaurants, and consumers (Gutierrez et al., 2016; Ross Strategic et al., 2020). However, it is uncertain to what degree these approaches have translated into meaningful progress toward sustainability within the global fisheries sector: the majority of seafood remains uncertified, most participating fisheries have been certified for less than five years, and independent verification of sustainability improvements for fisheries that have been certified or are in the process of certification are scarce (Blackmore et al., 2015; Certification and Ratings Collaboration, 2020). Although it has been difficult to quantify the ecological gains resulting from market-based approaches in general (Ross Strategic et al., 2020), there is evidence that certification, ratings, and improvement programs have resulted in tangible sustainability benefits (Blackmore et al., 2015; Carlson and Palmer, 2016; Cannon et al., 2018).

Another key category of market-based interventions includes a broad set of capacity building efforts focused on empowering reef stakeholders. These efforts aim to increase sustainability by improving fisher livelihoods, as insufficient fisher income can be a catalyst for engaging in unsustainable fishing practices (Purcell et al., 2016; Conservation International, 2019). This category includes three types of activities that empower fishers to more directly engage in markets to enable higher incomes from fishing and disincentivize unsustainable fishing practices: (1) providing fishers with real-time information on the market value of their catch, (2) training communities in improved post-harvesting seafood processing methods, and (3) forming fishers associations/cooperatives (Table 1; Bell et al., 2018).

Most coral reef fisheries are small-scale: they typically involve simple harvesting practices and gear, supply small local and/or informal markets or direct subsistence, and operate in remote locations distant from international markets (Teh et al., 2013; Leenhardt et al., 2016). As most coral reefs are located along the coastlines of developing countries with low fisheries management capacity, coral reef fisheries are generally unmanaged or undermanaged, and most are unassessed (i.e., no catch or effort data exist; Pauly and Zeller, 2014; Friedlander, 2015). These fisheries are complex, with the majority targeting multiple species and individual fishers utilizing various gear types and engaging in multiple fisheries sectors.

Following a previous convention developed for fisheries in general (Pauly and Zeller, 2015), we segregate reef fisheries sectors into three general archetypes: industrial, artisanal, and subsistence (Table 1). Although debates exist about the precise delineation of these fisheries archetypes, the classification scheme we utilize here defines industrial reef fisheries as large-scale and commercial, requiring high investment in larger vessels and higher technology gear, and targeting high-value species in high volumes for export. We define artisanal reef fisheries as small-scale and commercial, employing smaller vessels and lower technology gear, and including high- to moderate-value species for export or domestic markets. Most commercial coral reef fisheries are artisanal and supply the live reef food fish, chilled/frozen fish, and aquarium trades (Wabnitz et al., 2003; Sadovy de Mitcheson and Yin, 2015). Artisanal fisheries also supply local and regional restaurants, hotels, grocery stores, and fish markets, with higher value fishes typically consumed by tourists (Bevilacqua et al., 2019). However, most coral reef fisheries are likely non-commercial or subsistence and include lower value fishes whose consumption is restricted to a household or village. The non-commercial nature of subsistence fishing means that catch is largely unreported but may comprise up to 80% of total coastal fisheries production in some countries (Dalzell et al., 1996; Grafeld et al., 2017). Underreporting of artisanal fisheries catches destined for domestic markets is widespread as well; these fisheries are largely unmonitored by the governments of developing countries whose limited resources are typically focused on industrial export-oriented fisheries (Sale, 2008).

Among the diversity of reef fisheries globally, it is widely recognized that export-oriented fisheries face the greatest sustainability challenges. The aquarium trade supports livelihoods in predominantly rural and low-income communities and provides high value products primarily to consumers in the developed world. It could therefore provide strong economic incentive for communities to conserve coral reef ecosystems. However, damaging fishing techniques, over-harvesting, and high mortality levels of reef organisms from inadequate handling and transport remain significant barriers to sustainability (Wabnitz et al., 2003). The live reef food fish (LRFF) trade is particularly unsustainable: it targets long-lived and large-bodied fishes that are easy to overexploit and can take generations to recover. Further, it is largely unregulated, demand-driven, and geographically broad and therefore untethered from local supply, and it incentivizes overexploitation because the value of a species increases with rarity (Sadovy and Vincent, 2002; Sale, 2008). The LRFF trade has caused the near extirpation of several of the largest reef fishes such as Napoleon wrasse, bumphead parrotfish, and several groupers (Blackmore et al., 2015; Sadovy de Mitcheson and Yin, 2015). The magnitude of trade in chilled and frozen reef fishes is not well known; it is therefore difficult to assess the sustainability status of this fishery. However, because it is targeting many of the same species overexploited by the LRFF trade as well as ecologically important herbivorous fishes, this industry is likely highly unsustainable (Sadovy de Mitcheson and Yin, 2015). The beche-de-mer trade has resulted in the rapid overfishing of sea cucumber populations on reefs globally, resulting in local extirpations in several locations (Purcell et al., 2013). Sea cucumbers are easily overexploited due to the ease with which they are caught, their slow reproductive rates, and susceptibility to Allee effects due to their broadcast spawning of gametes (Uthicke et al., 2004). Supply chains for artisanal and industrial coral reef fisheries are extremely complex and varied, further complicating reform efforts (see Supporting Information).

To quantify the extent to which coral reef fisheries are entering market channels (and therefore may be amenable to market-based approaches), we compiled catch and landed values of coral reef fish and invertebrate taxa from 1950–2014 available from the Sea Around Us Project (SAUP). SAUP provides catch reconstructions based on landings data by taxon and country reported by the Food and Agriculture Organization of the United Nations (FAO) and supplemented with additional data sources and statistical models to improve data accuracy and completeness (Pauly and Zeller, 2015). From SAUP’s online database, we compiled catch and landings values for all taxa that were reported to occur in coral reef environments in at least 25% of observations and for countries that contain coral reef habitat in their EEZs (per Teh et al., 2013). We compiled data at the finest taxonomic resolution possible, and included statistics at the level of species, genus, or family (Supplementary Table 1).

Our analysis shows that commercial coral reef fisheries (i.e., industrial and artisanal) catches have increased dramatically since 1950, and today account for 9% of all marine catch and 13% of landed value of marine catch (Figure 1). This result supports qualitative observations that reef fisheries in developing countries have transformed over the past half-century from primarily a subsistence and social activity to a commercial activity (Sadovy de Mitcheson and Yin, 2015), due to improvements in transportation technology and storage and higher market value and increasing tourism (Kronen et al., 2006; Smith and Zeller, 2016). Therefore, in theory, market-based approaches may be suitable for commercial coral reef fisheries that have access to markets where sustainability is a concern and/or where the application of market-based approaches will result in stakeholder buy-in due to tangible social and/or ecological improvements. However, these figures significantly underestimate subsistence catches on coral reefs, which make up the majority of catch in many parts of the world (Dalzell et al., 1996; Sale, 2008). Lastly, these data show that catches on reefs peaked in the 1990s or 2000s and have steadily declined since (Figure 1), a clear indicator of overfishing and confirmation of the need for improved sustainability in these fisheries.

Due to a general lack of scientific information and fisheries management infrastructure and the high reliance of local communities on reef species for food security, traditional regulatory approaches are typically more difficult to implement and enforce for coral reef fisheries (Sadovy, 2005; Friedlander, 2015). As a result, a small subset of regulatory approaches that are relatively simple to follow and enforce are most appropriate for coral reefs (Table 2).

Access rights (such as individual transferable quotas, territorial use rights in fisheries-TURFs, and catch shares) and temporal and geographic restrictions (including marine protected areas) have had positive ecological outcomes with non-reef fisheries but may not be appropriate for most coral reef fisheries because they require strong governance, monitoring, and enforcement. For the same reasons and because many fishers view it as cultural and economic right to fish their local reefs (Brewer, 2011; Cinner, 2014; Birkeland, 2017), catch-based restrictions are difficult to implement for many reef fisheries. In contrast, effort restrictions on highly efficient or damaging gear (including cyanide, dynamite, SCUBA, gillnets, and traps) may be more socially acceptable and relatively easier to implement and enforce (McClanahan and Cinner, 2008; Brewer, 2011; Friedlander, 2015). In places with a recent history of customary governance, traditional approaches such as Customary Marine Tenure, co-management or participatory management, and community based individual transferable quotas may hold promise (Aswani and Sabetian, 2010; Friedlander, 2015; Gardner et al., 2017). For intensive export-oriented coral reef fisheries that have inherently unsustainable elements such as the LRFF, aquarium, and beche-de-mer trades, trade policies such as moratoria on commercial sale, export limits or bans, import bans, and tariffs are most appropriate due to the threatened status of fished species and relatively greater management and governance focus placed on these fisheries (Sadovy, 2005; Purcell et al., 2013; Dee et al., 2014; Ram et al., 2014). Import and export restrictions that have been implemented for reef species have resulted in recovery of stocks in some cases, depending on length of moratoria, degree of enforcement, and species (Friedman et al., 2011). Key exporters of live reef food fish and aquarium species in Southeast Asia, Pacific Islands, and Caribbean have recently taken important steps toward reducing take of vulnerable species via bans on commercial fishing and/or export of certain species (Sadovy de Mitcheson and Yin, 2015). For the aquarium trade, import and export restrictions have shown success when combined with moratoriums on the sale of depleted species, no-take reserves, and tiered quota systems and should be implemented more broadly across this sector (Dee et al., 2014, see Supporting Information for more detail). Government controls on the volume of aquarium specimens exported have also been effective at increasing price points because rarer fish fetch higher prices (Rhyne et al., 2014). However, because many reef fishers are reliant on fishing for their sole source of income (Cinner, 2014; Purcell et al., 2016), the restriction or banning of one fishing activity may result in shifting to fishing unsustainably or illegally on other reef resources (Conand, 2006; Purcell et al., 2016).

Our analysis shows that specific market-based interventions have the potential to increase the sustainability of some reef fisheries. However, these interventions are more likely to be successful when matched to the specific characteristics of the fishery, market, and governance systems. For high value, export-oriented reef fisheries destined for markets with lower engagement in seafood sustainability (i.e., Asia), regulatory approaches in the production geography are the most likely to be effective. This includes import and export restrictions, which hold the greatest promise for regulating markets to reduce highly unsustainable and IUU fisheries such as live reef food fish and beche-de-mer. For high-value, export-oriented species destined for markets with a high level of engagement in sustainability, practitioners should look to certification and ratings efforts, fishery improvement projects, and purchasing commitments from buyers, which hold the greatest promise for fisheries for highly fecund invertebrates such as lobsters (and perhaps mollusks such as octopus). For the aquarium trade, which contains high-value products for export to largely engaged markets but with geographically varied, extremely diffuse and complex supply chains, traceability and transparency efforts may hold greater promise than certification and ratings schemes, which have failed in these fisheries in the past (Supporting Information). For artisanal fisheries targeting species for domestic or regional consumption, sustainable purchasing commitments from retailers, consumer awareness campaigns, and local certification and ratings schemes may help shift attitudes toward sustainability and increasing food security for local communities. Finally, fisher empowerment efforts including access to market information, training on improved post-harvest handling and processing, and formation of fisher associations and cooperatives hold promise for increasing fisher incomes, reducing wasteful catch, increasing food security, and de-incentivizing unsustainable practices.

While certification may only be economically viable for a select group of coral reef fisheries, engagement in the pre-certification process (i.e., via FIPs) may nevertheless increase the long-term sustainability for “uncertifiable” coral reef fisheries. FIPs utilize market incentives to drive the development of fisheries management plans, harvest control rules, scientific information on stock status, and governmental support in terms of enforcement and development of fishery policies. These improvements are correlated with positive sustainability outcomes for fisheries in general (Cannon et al., 2018; CEA, 2020a), and could be a powerful catalyst for increasing small-scale coral reef fisheries management capacity in developing countries.

Despite the potential of market-based interventions, specific approaches must be carefully tailored to the ecological and social contexts of these systems. For reef species where certification and FIPs may be viable, several measures must be implemented to promote meaningful improvements to sustainability. These include considerations of ecosystem effects of the fishery, including selecting appropriate spatial scales so that a specific fishery is managed cohesively in a wider ecologically connected seascape (Kittinger et al., 2021). These “jurisdictional approaches” (Kittinger et al., 2021) could be a solution for markets to source from regions where management systems recognize the tight link between the productivity of reef fish stocks and the ecological integrity of the coastal habitats they utilize at various life stages (coral reefs, seagrasses, and mangroves), and accounting for synergistic effects of fishing and other human stressors, including climate change and pollution (Pratchett et al., 2008). Other voluntary private sector commitments such as sustainable sourcing policies and sustainability ratings systems can also play a role in catalyzing consumer and governmental support for improving fishing practices on coral reefs. However, due to the inability of most reef species to supply commercial markets in a sustainable manner, traditional regulatory approaches must be implemented in tandem with private sector initiatives and capacity building approaches to ensure fishing effort is kept within sustainable levels. A robust collaboration between governments, non-governmental organizations, and fishing communities could ensure that the complex social-ecological system of reef fisheries is considered so that livelihoods are improved without increased damage to reef ecosystems (Blasiak et al., 2017).

Market-based interventions have been part of the landscape of fisheries conservation initiatives for over a decade. A myriad of tools and resources have been developed to support these efforts, including (for example) guidance on certifications (e.g., Marine Stewardship Council, 2019), fishery improvement projects (Conservation Alliance for Seafood Solutions, 2021), marketing of sustainable seafood (UC Santa Barbara, 2014) and much more. Some of these mechanisms have highly developed indicators and evaluation processes to determine sustainability (e.g., to meet the criteria for certification), while others are more nascent with respect to how they set standards and evaluate impact. Additionally, the theories of change underpinning these approaches can vary both in terms of the intervention (e.g., consumer education versus export regulations) and the specific geography, production mode (i.e., aquaculture versus wild-capture fisheries) and other factors. The diverse set of market-based strategies also continues to evolve, as practitioners, researchers, and advocates continue to meld, shape, and innovate in the field. Last, a growing literature has begun to evaluate the impacts of these initiatives (CEA, 2014, 2020a,2020b; Carlson and Palmer, 2016; Cannon et al., 2018; Travaille et al., 2019; Arton et al., 2020), but it is still a relatively underdeveloped space in terms of science and evidence, which provides ample opportunity for researchers seeking to evaluate these practices and their level of impact on nature and people.

Ultimately, markets will continue to shape coral reef outcomes, driven by increased demand, limited production, and the shifting ways in which communities, reefs, and economies interact. Given the pervasive influence these economic activities continue to have on reefs, our analysis shows there is much that may be gained by exploring market-based solutions to confront the coral reef crisis. This will require practitioners and researchers alike to look beyond the reef itself, and to think creatively about “off the hook” solutions that engage supply chains, market actors, and regulatory solutions that can incentivize sustainable practices in the Anthropocene.

With few exceptions, coral reefs cannot sustainably support industrial fishing activities, and especially those that flow into high-volume export markets. For this reason, and to ensure food security for local communities, most reef species (except for a select number of highly fecund invertebrate species such as lobsters and mollusks) should be consumed locally. Sustainability appears to be achievable for reef fisheries under select conditions: traditional management approaches have enabled long-term sustainable use of coral reef resources for local consumption (McClenachan and Kittinger, 2012; Pauly and Zeller, 2014). However, traditional fishing practices have given way to use of highly efficient modern gear, and village consumption of reef resources is giving way to market-oriented fisheries production (McClenachan and Kittinger, 2012). A strong case can be made for shifting commercial fishing away from coral reefs altogether and focusing it instead on tropical pelagics, as these species are harder to overfish and recover more quickly when overfished (Birkeland, 2017). In some Pacific Island nations, governmental policies have encouraged dietary shifts that have driven consumption away from reef fisheries and promoted recovery of fish stocks (Bell et al., 2009). It is therefore imperative that market-based interventions do not increase fishing effort on reefs, for example by linking additional coral reef fisheries into global markets or creating new markets for fisheries that are already depleted or fully fished (Stratoudakis et al., 2016). Finally, to allow reef fisheries and reef ecosystems to recover, the current transition away from wild capture coral reef fisheries and toward aquaculture and mariculture of highly fecund, low trophic level species (such as lobsters, beche-de-mer, and ornamental species) must continue (Hair et al., 2002; Lovatelli et al., 2004; Bell et al., 2009).