Socio-ecological impacts of industrial aquaculture and ways forward to sustainability

Keywords: sustainable development, blue revolution, environmental impacts, social justice, fish farming.

The role of aquaculture in the worldwide seafood supply is currently undeniable. With 82.1 × 10⁶ tonnes (Mg) of food fish (US$250.1 billion) produced in 2018 and an annual growth of 5.3% for the period 2001 through 2018, the contribution of aquaculture to the total seafood production was 46% in 2016–18 (Food and Agriculture Organization of the United Nations 2020). Considering these numbers, the growing population, urbanisation, and consumption projections (Foley et al. 2011; Cohen 2003), as well as the scientific evidence of overexploitation of fish stocks (Jackson et al. 2001), there is a high probability that aquaculture will continue increasing.

Aquaculture can contribute to food and nutrition security (Kawarazuka and Béné 2010), economic growth, export revenue, foreign exchange and poverty reduction (Edwards 2000; Filipski and Belton 2018; Engle and Bohorquez 2019). With the advent of industrial or intensive food production systems in the last half of the past century, modern food production systems have greatly increased productivity by requiring a high ratio of inputs at a high environmental cost (Gowdy and Baveye 2019). In particular, the increase in seafood production has been accompanied by a rise in environmental impact (Black 2001; Martinez-Porchas and Martinez-Cordova 2012; Cretu et al. 2016). In fact, some aquaculture activities are said to contribute to the decline of global seafood (Rönnbäck et al. 2002) and are, hence, nicknamed ‘the fake blue revolution’ (Deb 1998).

Although conceived for industrial shrimp farming, the categorisation of perceptions around this activity put forth by Béné (2005) could apply to all industrial aquaculture activities producing socio-ecological impact. Béné (2005) distinguished between the political ecology (PE) and the best management practices (BMPs) discourse. For those supporting the PE discourse, political changes are urgently needed if the shrimp farming industry aims to benefit the poor and have little environmental impacts. For the BMP supporters, the problems that have arisen in the industrial shrimp culture can be solved by better management practices and technology.

Sustainable development is widely understood as the interlinked goal of environmental protection, social equity, and economic prosperity, albeit the term has been considered by many authors as internally self-contradictory or an ‘oxymoron’ (Johnston et al. 2007; Brand 2012; Purvis et al. 2019). In favour or against the general sustainability concept, it is clear that if aquaculture is to be sustainable in the long term, it must consider the whole socio-ecological system (Gallopín 2003). Therefore, it should protect the environment on which it depends, be socially accepted and provide economic benefits in a balanced way. When this balance is broken, social and environmental impacts arise.

Having a general picture of the socio-ecological impact related to industrial aquaculture and its possible solutions may be instrumental in the path towards sustainability. A better knowledge of these disturbances can also shed light on the factors limiting aquaculture expansion (Galparsoro et al. 2020). A great effort in reviewing the environmental impact of world aquaculture (Martinez-Porchas and Martinez-Cordova 2012) and its contribution to food security and nutrition (HLPE 2014) has been made. Nonetheless, additional social aspects such as conflicts and social inequities have received little attention.

Several new practices and feed and health alternatives have been gaining increasing attention in recent decades. Recirculating aquaculture systems (RAS) and biofloc technology (BFT) among other technologies that reduce the use of water and, therefore, discharges, are gaining acceptance among farmers and, at the same time, contributing to sustainability (Bossier and Ekasari 2017; Li et al. 2018). It seems that, to a certain extent, industrial aquaculture is regulating itself by searching for alternatives to unsustainable practices to secure its own future.

In this study, a non-systematic literature review of peer-reviewed articles dealing with the ecological and social impact of industrial aquaculture has been conducted to provide an overview of the challenges facing industrial aquaculture. The second aim of the present study was to identify the main socio-ecological impacts related with industrial aquaculture and alternatives towards sustainability. Final categories of socio-ecological impacts and ways forward to sustainability were discerned through literature reading.

The lack of proper management, planning and enforcement in the aquaculture industry has been indicated as a major threat to the environment and social welfare of some areas where they have established.

Major ecological hazards of industrial aquaculture are presented here as follows: (i) the damage and destruction of natural environments, (ii) discharges, and (iii) the risk to wild fish and shellfish populations.

Industrial aquaculture has been associated with coastal lowlands’ loss, among which mangrove forest destruction is the greatest concern (Páez-Osuna 2001; Polidoro et al. 2010). This coastal transformation leads to the loss of ecosystem services provided by mangrove forests, such as coastal protection, the stabilisation of sediments, the absorption of pollutants, the provision of livelihoods for coastal communities and a safe habitat and feeding area for terrestrial and aquatic animals (Primavera 1998; Ashton 2008). The problems associated with this coastal transformation are exacerbated by the short life span of ponds (5–10 years). Eutrophication, the accumulation of toxins, sulfide-related acidification, and crop diseases (Wolanski et al. 2000) eventually lead to the abandonment of the ponds, after which farmers move on to a new area of mangrove (Wolanski et al. 2000; Valiela et al. 2001).

Nonetheless, in the past two decades, major concerns associated with habitat loss have triggered conservation policies in some countries where, although mangroves continue to be destroyed, the rate has slowed down (Kozhikkodan Veettil and Quang 2019; Sampantamit et al. 2020).

Also called effluents or aquaculture waste, discharges contain the organic matter, nutrients, chemicals, therapeutics, and higher levels of salt that may remain in the system after harvesting (Sindilariu 2007). Uneaten feed, faecal excreta, dissolved excreta and overfertilisation are the origin of organic and nutrient loading in aquaculture practices. The effluent content may vary depending on some factors such as stocking density or the species cultivated (Islam 2005). In rainbow trout (Oncorhynchus mykiss) farming, uneaten feed accounts for 4% of the total feed. In addition, ~19% of organic carbon (OC), 13% of total nitrogen (TN), and 55% of total phosphorous (TP) of the ingested feed is excreted as faeces and 36% of TN and 9% of TP as dissolved excretion (Sindilariu 2007). In cultivated salmon in Chile, 25% of incorporated feed is extracted as fish biomass and 75% loaded into the ecosystem (Buschmann and Fortt 2005).

Part of the loading will stay in the water column and move with the currents and the rest will be deposited in the sediments. The fate of the effluent will vary according to its characteristics and the hydrodynamics. In total, 79% of C, 88% of TN and 95% of TP (equivalent to 23% of C, 21% of N and 53% of P of the feed input) of the rainbow trout-farm effluents will be accumulated in the sediment and become unavailable (Wu 1995). Before being accumulated in the sediment, nutrient and organic loading is deposited, producing bacterial mats and anoxic conditions if the benthic feeding capacity is overwhelmed, which, in turn, generates hydrogen sufide and methane, affecting both the farm and the environment (Silvert 1992).

Impacts of nutrient loading on local ecosystems have been documented worldwide. Aquaculture discharges have been associated with hypereutrophication events (Sorokin et al. 2006). Harmful algal blooms have been documented inside shrimp (Litopenaeus vannamei) ponds in Mexico (Alonso-Rodríguez and Páez-Osuna 2003). Macrobenthic community changes have been observed along the effluent-enriched gradient of a farm, with a decrease in benthic diversity (Tsutsumi et al. 1991; Wu et al. 1994) and the existence of symptoms of disturbance (Karakassis et al. 2000). In the Mediterranean Sea, sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) farms negatively affect the benthic ecosystem engineer species Posidonia oceanica in distances up to 200 m away from the cages (Holmer et al. 2003). In the Philippines, milkfish (Chanos chanos) farm discharges are negatively affecting coral settlement (Quimpo et al. 2020). In eastern Asia and South-east Asia, long-term exposure to nutrient pollution from aquaculture effluents can ultimately lead to a complete loss of seagrasses (Thomsen et al. 2020).

Other pollutants found in aquaculture effluents are chemicals and therapeutics. They are used mainly to prevent fish disease, kill harmful biota and disinfect. Variation exists in the use of antibiotics in aquaculture among countries, with 13 authorised antibiotics in China and 5 in the UK (Liu et al. 2017). Those substances can have direct toxic effects on biota, and, in the case of antibiotics, produce antibiotic-resistant pathogens (Willis 2000). Antibiotics are the most used drugs, but hormones, antifungal agents, growth promoters and sedatives, among others, are also used in industrial aquaculture (Bottoni et al. 2010).

Finally, industrial aquaculture discharges can affect the salinity of surrounding waterbodies. Concretely, shrimp farm activities have been associated with the salinisation of drinking water wells in many Asian countries (Primavera 1997; Patil and Krishnan 1998). Salinisation by shrimp farming has also been documented to affect aquifers and lagoons in other parts of the world (Cardoso-Mohedano et al. 2018; Naus et al. 2019).

All the above-mentioned ecological impacts can pose threats to wild fish and shellfish biota. In addition, the following four more hazards have been acknowledged: (i) the destruction of fish and shellfish by-catch during shrimp fry gathering, (ii) the dependence on fish oil and fish meal. (iii) the threats that farmed fish pose to wild fish populations, and (iv) the pressures that exotic farmed species pose to the ecosystem.

It has been documented that for each tiger shrimp (Penaeus monodon) fry caught, ~26 other shrimp species, 29 finfishes and 70 zooplankton are being simultaneously destroyed in Bangladesh (Deb 1998). In Sundarbans (India), ~50 species of finfish and 28 species of shellfish are lost per net and day in the tiger shrimp fry collection (Das et al. 2016). Declining fish catches has been observed in Bagerhat District (Bangladesh), probably being linked with juvenile by-catch during freshwater prawn (Macrobrachium rosenbergii) larvae collection (Ahmed and Troell 2010). Not only shrimp and prawn are subject to being stocked wild-caught, but also milkfish, tuna and eels, producing all together with shrimp fry collection, the loss of billions of fish and shellfish fry (Naylor et al. 2000).

The growing industrial aquaculture and its use of fishmeal and fish oil has raised concerns over its potential to increase overfishing (Olsen and Hasan 2012). The dependence on fishmeal and fish oil biomass of industrial aquaculture can increase up to 2.5–5 times as fish biomass is produced for carnivorous species (Naylor et al. 2000). Additionally, the global consumption of marine pelagic species for aquafeed surpassed by 1 × 10⁶ to 2 × 10⁶ Mg the production of finfish and crustacean species aquafeed-dependent in 2002 (Tacon 2004).

Interactions between wild and domesticated fish populations poses two hazards, namely, (i) interbreeding and (ii) disease and parasite transfer. Interbreeding between genetically different aquaculture escapees and wild populations can negatively affect the fitness, productivity, local adaptation, and genetic variability of the wild fish populations (Mikkelsen 2007). Interbreeding affects not only wild fish but also farmed fish. Concretely, the wild Atlantic salmon (Salmo salar) gene pool can become crucial in developing future farmed stocks when a new gene selection cycle starts again after 10 generations (Liu et al. 2011). However, Bjørn and Finstad (2002) suggested that salmon farms in Norway contribute to the elevated sea lice (Lepeophtheirus salmonis) level in wild fish as sea lice production has been observed to be connected with farmed fish production (Heuch and Mo 2001).

The use of non-native species in freshwater industrial aquaculture has raised great concerns as the introduction (accidental or intentional) of non-native species has caused great economic, ecological and social disturbances worldwide (Mack et al. 2000; Vitule et al. 2009). In Brazil, aquaculture is widely focused on alien species and genotypes (Nobile et al. 2020), following the pattern of a worldwide steadily increasing dependence on alien freshwater finfish in aquaculture (De Silva et al. 2009).

The major social threats from industrial aquaculture are presented here as follows: (i) spatial conflicts, (ii) threats to food security, (iii) unfairness in access to commons, and (iv) unequal distribution of benefits.

Industrial aquaculture activities often collide with other uses and users of land and sea. A competition exists for sea space with commercial and recreational fisheries. The loss of available fishing grounds, reduced fishing capacity, navigational disturbances and possible disease transmission to wild fish populations have been reported in areas where aquaculture was installed and are some of the causes of this competition (Israel 2007; Chang et al. 2014; Clavelle et al. 2019). In Bandon Bay (Thailand), small scale fishermen lost their right to fish in areas declared cultivable for aquaculture by the Department of Fisheries (Ratchatapattanakul et al. 2017). Recreational fishers in Ireland claim salmon farms are responsible for the sea slice disease in sea trout wild populations. Although without clear evidence of the relationship between farms and sea trout disease, wild populations collapsed in 1989, and five fishery owners sued four salmon farmers for damages (Phyne 1996).

The aquaculture structures can also lead to conflict with the tourism industry and residents for environmental and aesthetic reasons (Kurtoglu et al. 2010; Hanes 2018). In Sumatra, the water quality of Lake Toba has deteriorated, with cage fish aquaculture discharges as one of the major causes. The government’ decision to transform the region into an international tourism destination is in direct conflict with fish farming activities (Tanjung and Hutagaol 2019). Fishing sector opposition and environmental concerns towards the salmon farming industry in British Columbia (Canada) led to a 2-year moratorium on the establishment of new salmon farms (Noakes et al. 2003), and the government is now considering an outright ban of sea-based salmon farming.

Agriculture can also compete for space with industrial aquaculture as has been observed in the ‘rice bowl’ of Vietnam, the Mekong Delta. The rice cultivation area has decreased from 970 000 ha in 2000 to 800 000 ha in 2002. The conflict in the use of land and water resources reached a peak in 2001 when shrimp farmers broke a major dam at the Lang Tram sluice to allow saline water into the area (Dung et al. 2009).

Although aquaculture has an undeniable role in food security (Béné et al. 2015; Rajee and Mun 2017), the opposite is also true for some types of aquaculture. In fact, on a global scale, regions with low undernourishment are net importers of seafood from regions with high undernourishment (Smith et al. 2010).

The conversion of agricultural lands devoted to staples into ‘cash crop’ aquaculture, the loss of access to marine resources, the loss of small fish populations, and the decline of nearshore fish and shellfish because of mangrove deforestation, can negatively affect food security. In Kerala (India), industrial aquaculture contributes to food purchase power by creating jobs, albeit the conversion of paddy fields into prawn farms is considered a major threat to household food security (Srinath 2008). Nickerson (1999) stated that farmed shrimp in the Lingayen Gulf (Philippines) contributes to the nation’s export revenue but does little for the nation’s food and nutrition supply. In fact, mangrove areas contribute more to food security among other equity indices than do farmed areas by distributing benefits to the largest population most dependent on the resources for their nutrition and livelihood (Nickerson 1999).

The placement of a fish farm in a common area results in de facto or formally established privatisation. This privatisation has been observed to increase inequality in the distribution of benefits and resources (Adger and Luttrell 2000). Conflict arose when the previous common areas were used by the community for recreational purposes and fishing and shellfish collection among other uses, eventually turning into a threat to local livelihoods. Officially, lagoons in Vietnam are government property, but Tam Giang Lagoon has been de facto privatised by industrial aquaculture farms since the early 1990s, excluding poorer fishermen from most of the fishing areas (Huong and Berkes 2011). The same privatisation process was observed in Giao Lac (Vietnam), where the spread of private leaseholds in the coastal area for clam farming have resulted in the loss of access to mangrove resources for poorer groups with no capital to invest in clam or shrimp farming. In this situation, women are the most vulnerable, especially because of the social constraints they face regarding access to land rights and well-paid jobs (Hue 2006). Those examples are part of the Vietnamese economic reform launched in 1986 known as doi moi, where privatisation and free market were encouraged, and short-term land-use rights were introduced (Hue 2006). Coastal populations in Ecuador have faced the same fate, with shrimp farms progressively dispossessing them from their traditional access to mangroves (Veuthey and Gerber 2012). Another example of unfairness in access to commons was observed in the Faroe Islands, where small-scale lobster fishers claimed having been illegally displaced by the salmon farm industry (Bogadóttir 2020).

Illegal farming brought forth de facto privatisation and the marginalisation of the users of previous common resources. Although the high court declared illegal all aquaculture in Chilika Lake (India) in 1993, shrimp aquaculture grew steadily under the control of local interests, albeit illegally, and de facto privatisation of the lake developed (Adduci 2009). The illegal farming led to conflicts between people related to informal aquaculture and the traditional fishermen, resulting in unsolved murders of traditional fishers (Adduci 2009).

It has been observed worldwide how local communities receive few socioeconomic benefits from industrial aquaculture in their areas but suffer the environmental burdens of it. Highly capitalised, vertically integrated, and export-oriented aquaculture enterprises are regarded as socially disconnected from local communities and with little contribution to local economies (Tiller et al. 2012; Ertör and Ortega-Cerdà 2015; Young et al. 2019; Bogadóttir 2020). Moreover, unfair distribution exists as well in all the above-mentioned cases where communities have lost the access to resources for livelihood. In Bangladesh, those who have the technology and the capital necessary for adopting new culture systems gain benefits from aquaculture (Deb 1998). The poorer gained little through aquaculture employment and lost much through the hindering of access to grazing lands, environment deterioration and even the loss of their own lives (Deb 1998). In short, poor governance and corruption prevent the poor from accessing the benefits of seafood export revenues (Smith et al. 2010).

The reviewed literature suggests that social and ecological impacts are deeply intertwined, upholding the need to focus not only on the ecological sphere but on the whole socio-ecological system. Social rejection was observed when the maximum level of impact accepted by the community was surpassed. This social rejection of industrial aquaculture was related to the perceived or real (i) destruction of natural environments, (ii) the impact related to discharges, (iii) risks to wild fish and shellfish populations, (iv) the conflict with other land and sea uses, (v) threats to food security, (vi) the unfairness in access to commons, and (vii) the unequal distribution of benefits.

Three measures could help address mangrove loss. First, spatial-based tools can properly allocate the different coastal uses. Second, ‘mangrove-friendly aquaculture’ can be adopted in mangrove conservation and restoration sites. Finally, the adoption of economic incentives and disincentives can help create a more sustainable behaviour in communities (Primavera 2006).

The unsustainable dependence on fish feed and fish oil of farmed species can be addressed with alternative protein sources. Those sources can be by-products and materials not suitable for direct human consumption (Nyina-Wamwiza et al. 2010), without forgetting the great potential of microalgae as aquaculture feed (Adarme-Vega et al. 2012). However, because the poor protein digestibility of alternative feed can enhance feed waste (Cho and Bureau 2001), a balance is needed. The same authors recommended an appropriate feed composition or formulation, feeding frequency and a prediction of fish growth to reduce waste output.

To address discharges, there are some farming technologies that minimise them and, therefore, contribute to the ecological sustainability of industrial aquaculture. Some examples are the following: biofloc technology (BFT), integrated multi-trophic aquaculture (IMTA), recirculating aquaculture systems (RAS), integrated aquaculture–agriculture systems (IAAS) and organic aquaculture. In RAS, only 10% of the total water volume is needed to be replaced on a daily basis (Twarowska et al. 1997). Ammonium and organic matter are transformed into NO₃ and CO₂ in the bio-filtration units by bacteria (Gichana et al. 2018), and solid wastes are separated from water by solid-separation units and discharged as sludge (Chen et al. 1997). In spite of the advantages, RAS still present some challenges (Gichana et al. 2018), and the high operational costs prevent their wide application. In contrast, BFT is a microbial-based system with zero water exchange, where waste nutrients are recycled into microbial biomass that, in turn, becomes feed for cultured animals (Crab et al. 2012). Biofloc technology (BFT), although in its infant stage (Bossier and Ekasari 2017), offers a series of undeniable advantages, including low feed and water input, the enhancement of immunity and antioxidant status of cultured animals, an increased crop yield and economic feasibility (Pérez-Fuentes et al. 2013; Ekasari et al. 2015; Ahmad et al. 2017). However, for its management, BFT needs skill capacities, continuous aeration and further research (Crab et al. 2012). Biofloc technology (BFT) has also proved to have synergistic effects when combined with IMTA systems (Liu et al. 2014). Before IMTA was given a name, it had been practiced for centuries in Asia (Neori et al. 2007). Integrated multi-trophic aquaculture (IMTA) grows species from different trophic levels on the same site with the peculiarity that one species’ by-products become energy, fertiliser, and feed for the others. In this polyculture system, extractive crops, usually algae, use dissolved inorganic nutrients from the waste of fed crops (fish or shrimp) to produce algal biomass and, thus, provide protein-enriched feed to fed crops (Nobre et al. 2010). Similarly, integrated aquaculture–agriculture (IAA) systems, generally practiced in different parts of Asia (Phong et al. 2008), can enhance aquaculture sustainability (Jana and Jana 2003). Finally, organic aquaculture, by using standards and certifications, can contribute to sustainability through its aim to provide safe and healthy food, while at the same time providing environmental, social and economic benefits to farmers and society (Biao 2008).

Vaccination and strict hygienic conditions can play a key role in reducing the use of therapeutics in aquaculture (Topp et al. 2018). In addition, prebiotics and probiotics are sustainable alternatives for promoting general health conditions (Dawood et al. 2019).

So as to avoid costly socioeconomic conflicts, a paradigm shift is needed in industrial aquaculture. Some key procedures have been identified to assist aquaculture towards granting a measure of social sustainability.

Improving governance and developing participatory processes to effectively engage stakeholders are two key aspects for ensuring success (Galparsoro et al. 2020). In addition, eco-labelled shellfish and fish grown in ecologically and socially responsible farms can encourage producers and consumers to support sustainability (Primavera 2006). There are two spatial-based tools with a high potential for enhancing the social acceptance of aquaculture; these are marine spatial planning and integrated coastal-zone management. The first has been widely promoted as an effective tool for reducing conflicts and impact (Lester et al. 2018), whereas the latter aims to integrate development and socio-ecological goals in coastal areas by following a holistic approach (Stead et al. 2002). In Norway, locally driven marine spatial planning where rights holders are involved in the decision-making gives legitimacy to the decisions about aquaculture siting (Young et al. 2019). Clear laws that delineate property and access rights in marine environments are essential (Young et al. 2019), together with governance improvement and fighting the corruption.

The different ways forward to sustainability, can be ascribed to the best management practice (BMP) discourse and the political ecology (PE) discourse. Different technologies to reduce effluents, the use of spatial-based tools, and feed and therapeutical recommendations could be assigned to the BMP discourse, while engaging stakeholders and developing laws to protect property rights and access to commons to the PE discourse. Taking a PE perspective, the difference between industrial aquaculture and traditional ocean fisheries is the privatisation of the commons (Hadjimichael et al. 2014). If not properly addressed and managed, this privatisation may lead to social injustice. The roots of socio-ecological disturbances cannot be found in the wickedness or ruthless exploitation of industrial aquaculture but in the inherent inequalities of each society where ecosystems and vulnerable communities are the ones internalising the externalities. Following this idea, basic livelihoods and water quality must be protected by constitutional law, and this law must be strongly enforced to guarantee social and environmental justice. A trade-off is needed between the promotion of an industry that generates capital income and the responsibility of maintaining ecosystems and the welfare of a community (Patil and Krishnan 1998). Aquaculture needs to be planned to not only meet the demands of the seafood markets but to attend to human needs, which will increase its social acceptance and developing community roots, in addition to corporate ones (Costa-Pierce 2002). Both BMP and PE can have synergetic effects in attaining sustainable industrial aquaculture, should they both be considered. Following this idea, community-run polyculture or integrated multi-trophic aquaculture (IMTA) systems, with existing laws that protect basic livelihoods and water quality, have a great potential for effectively reducing socio-ecological impacts while producing seafood. Further research would be needed on the socioeconomic and ecological benefits and applicability of such systems and the abovementioned technologies with reduced effluents. More research would also be desirable regarding alternative feed sources to effectively reduce the dependence on fish oil and fishmeal that at the same time are digestible enough not to enhance feed waste.

Once the effective perspectives are identified, it is important to discern the subjects that can probably contribute positively. In reducing externalities of aquaculture, everyone in the production chain counts, including consumers, producers, scientists, policy makers, farming business investors and coastal communities, among others. Everyone must be conscious of her own social and environmental responsibility when making decisions. Communities, science and media have already made a case for sustainable aquaculture through social movements and more than a thousand media and scientific productions dealing with environmental and social impacts of industrial aquaculture worldwide.

Industrial aquaculture has proved to be a powerful ally in producing seafood for a growing population. However, this production has been accompanied by socio-ecological disturbances. In the present study, seven major socio-ecological impacts have been identified through literature reading, namely: (i) destruction of natural environments, (ii) impacts related to discharges, (iii) risks to wild fish and shellfish populations, (iv) conflict with other land and sea uses, (v) threats to food security, (vi) unfairness in access to commons, and (vii) unequal distribution of benefits. It is noteworthy to mention that these impacts are not applicable to all industrial aquaculture, neither do they all occur simultaneously in every industrial aquaculture activity. The list aims to define the major impacts associated with the different types of industrial aquaculture that have been documented through literature.

Several alternatives have been acknowledged to contribute to ecological sustainability in industrial aquaculture, such as alternative protein sources, farming technologies that reduce effluents, and the use of probiotics. Additionally, improving governance, developing participatory processes, and applying spatial-based tools have been identified as instrumental in the transition towards social sustainability.

The urgency to satisfy a growing demand on seafood supply of an increasing human population, triggered the ‘blue revolution’ through the expansion of industrial aquaculture in recent decades. Now, the moral obligation of doing so respecting the environment and the social justice, calls for a paradigm shift from blue revolution to blue evolution.

The authors declare that they have no conflicts of interest.

The first author acknowledges a postdoctoral fellowship granted by DGAPA-Universidad Nacional Autónoma de México. This research has also received funding from the PAPIIT-UNAM grant IN300520 project.