Introduction

Aquaculture activities, especially shrimp and prawn cultivation, have gained prominence in the last three decades owing to the large-scale depletion of wild fish stocks and a growing worldwide demand for seafood (Naylor et al., 2000, Berkes et al., 2006, Cao et al., 2015, Pauly and Zeller, 2017). Alongside, many small-scale capture fishery systems have become aquaculture-oriented monoculture systems, causing shifts in fishing ecosystems, economies, cultures and societies worldwide (Naylor et al., 2000). Modifications in coastal habitats, the destruction of mangroves, and pollution and diseases from intensive culture (Huitric et al., 2002, Benessaiah and Sengupta, 2014) have contributed to the loss of local livelihoods and incomes and the collapse of fishery institutions. They have also resulted in poverty and the marginalization of a majority of small-scale fishers (Naylor et al., 2000, Nayak and Berkes, 2010, Marschke and Betcherman, 2016).

The growth of aquaculture has evaded these ecological, social and economic consequences. According to the 2016 FAO fish statistics report, world aquaculture production is increasing continuously and supply more than 44% of total global fish related demand (FAO, 2016). In Asia alone this increase is over 55 percentages. In 2014, world total aquaculture production stood at 73.8 million tones with an estimated first sale value of US$160.2 billion. Since the 1990s, Asia remains as the biggest producer of shrimp products (Barnaby and Vincent, 2007, FAO, 2016). Shrimp exports augmented annually, causing an increased demand from major consumer countries like the USA, Japan and the European Union, and the massive supply of low-wage local laborers (Islam, 2008) together with a simultaneous reduction of about 50-80% of mangrove areas in major shrimp-producing countries (Bush et al., 2010). This boom in the aquaculture industry has resulted in social, economic and ecological damage (Naylor et al., 2000, Bush et al., 2010). In this context, shrimp aquaculture has become a “wicked” driver causing (un)predictable and highly variable impacts on local social-ecological systems (Berkes et al., 2003). Following Jentoft and Chuenpagdee (2009) we define wicked drivers as those for which there is no known technical solution, it is not clear when and how they create impact, and there are no right or wrong methods that can be determined scientifically to respond to these drivers.

Influenced by international market trends and the rising export price of shrimp and prawn, as well as complementary policy provisions, aquaculture has become one of the dominant drivers of change across fish-producing countries of the world (Cascorbi, 2004, FAO, 2015, Béné et al., 2016, Brown, 2016). The resulting marginalizing effects of shrimp aquaculture are explicitly recognized in fisheries and aquaculture literature (De Silva and Davy, 2010, Benessaiah and Sengupta, 2014, Militz and Foale, 2017). Some believe that exponential aquaculture growth relieves pressures on marine resources and the natural stock of fish and contributes positively towards ecosystem and habitat modification (Naylor et al., 2000, Frankic and Hershner, 2003, Costa-Pierce, 2010, Pauly and Zeller, 2017). Others believe aquaculture has the potential to enhance local livelihoods and human wellbeing, and to empower small producers (De Silva and Davy, 2010, Galappaththi and Berkes, 2015b, 2016). However, the success of aquaculture can come with significant social and environmental costs. Commercial aquaculture enthusiasts forget that much expansion has come at the cost of small-scale capture fisheries that previously occupied areas into which aquaculture has presently expanded (Nayak and Berkes, 2010, Benessaiah and Sengupta, 2014).

Nayak and Berkes (2011) capture these two viewpoints on shrimp aquaculture’s contribution to ecosystem health and human wellbeing as processes of commonisation and decommonisation. “Commonisation is understood as a process through which a resource gets converted into a jointly used resource under commons institutions that deal with excludability and subtractability, and 'decommonisation' refers to a process through which a jointly used resource under commons institutions loses these essential characteristics” (Nayak and Berkes 2011: 132). Decommonisation helps understand the adverse effects of aquaculture as a driver that eventually contributes to the decline of customary capture fishery commons with immense social, economic, political, and ecological consequences. Inversely, the concept of commonisation is a lens to examine conditions in which aquaculture positively contributes to human wellbeing without causing significant harmful effects on the environment.

While decommonising effects of aquaculture are widespread and have received much attention in fishery literature, there is little or no published literature on aquaculture’s potential as a factor in commonisation. This paper aims to address this gap by examining the two faces of aquaculture: its decommonising and commonising roles. We use two cases from South Asia (Sri Lanka and India) which offer evidence that shrimp aquaculture activities can potentially contribute to either a process of commonisation or decommonisation depending on the context and the influences of cross-scale drivers. In the case of the Bay of Bengal coast of India, we discuss an example of aquaculture-led privatisation, i.e., de facto control of customary capture fishery commons through their systematic encroachment in Chilika Lagoon for more than three decades to explain how it caused decommonisation. Using the case of Northwestern Sri Lanka, we discuss collective action (Ostrom, 2014) initiatives around small-scale shrimp aquaculture to consider aquaculture’s role in creating the ground for commonisation that promises to reverse the process of decommonisation due to previously undertaken industrial shrimp aquaculture. We argue that aquaculture can strengthen the existing collective action to adapt to the changes in lagoon system or it can enable new forms of collective action fostering learning and innovation (Galappaththi et al., 2017). The challenge is to assess how, and if, key learnings from aquaculture’s role in the commonisation processes in Sri Lanka can be implemented to reverse processes of decommonisation elsewhere, such as in Chilika Lagoon.

Commonisation and decommonisation: The two faces of shrimp aquaculture

Given the possibilities surrounding success and failure, the two faces of shrimp aquaculture are a growing reality. The fisheries literature shows an expanding debate over the positive and negative impacts of shrimp aquaculture (Lebel et al., 2002, De Silva and Davy, 2010, Nayak and Berkes, 2010, Galappaththi and Berkes, 2014). A considerable group of literature highlights the positive role of shrimp aquaculture with particular attention paid to its economic benefits (Kongkeo and Davy, 2010). Umesh et al. (2010) studied the small-scale shrimp farmers of Andhra Pradesh on the east coast of India, who adopted a cluster-based approach to achieving better returns from shrimp farming. Here, cluster-based approach refers to a group of farmers whose ponds are situated within a specified geographical locality and all ponds are relying on the same water source. These farmers acted collectively through aqua clubs that led to positive outcomes such as improved shrimp production, better shrimp quality, and stable relations among actors in the market chain and less environmental impact. Kongkeo and Davy (2010) documented a case from Chacheongsao Province in Thailand, depicting how backyard hatcheries helped sustain a fast-declining large-scale shrimp industry. They found that small-scale owner-managed shrimp farms do well due to a reliable source of quality shrimp seed.

However, the success of shrimp aquaculture is not without adverse consequences, and often involves tradeoffs. Nayak and Berkes (2010, p. 565) underscore the point that “coastal management is a zero-sum game. As one type of use increases, it does so at the expense of another. Aquaculture is not spreading in an ‘empty’ seascape and landscape, but in many instances displacing small fishers who were already using those areas” as commons. There is an extensive body of literature that supports this position by focusing on the environmental and social (including economic and political) impacts of shrimp/prawn aquaculture. Environmental impacts include coastal modifications, loss of mangroves, pollution, and disease problems (Dierberg and Kiattisimkul, 1996, Primavera, 1997, Huitric et al., 2002). Bhatta and Bhat (1998) recorded how the emergence of commercial shrimp aquaculture triggered problems in the management of estuaries in coastal Karnataka, India. Some well-documented socio-economic impacts of shrimp aquaculture include privatization of public lands, marginalization, rural unemployment, migration, food insecurity, loss of institutions, and social unrest and conflicts (Primavera, 1997, Naylor et al., 2000, Huong and Berkes, 2011, Nayak and Berkes, 2011, Benessaiah and Sengupta, 2014, Béné et al., 2016).

The adverse impact of aquaculture on capture fishery commons has been examined by Nayak and Berkes (2011) as a process of decommonisation, whereas a reverse process of aquaculture contributing to the management of the fishery as commons is seen as a process of commonisation. Nayak and Berkes (2011, p. 133) defined the concepts of commonisation and decommonisation whereby commonisation is understood as a process through which collective action, institutions, rules and norms regarding excludability and subtractability are put in place, and decommonisation refers to a process through which each of these tend to lose these essential characteristics. They explain that excludability pertains to the decision regarding who is a user (a question of exclusion and inclusion), whereas subtractability deals with the rules of resource distribution and allocation within the users without which exploitation by one user will reduce resource availability for others. Both these characteristics of commons add to their complexity (Feeny et al., 1990, Ostrom et al., 1999, Battersby, 2017), generate new contestations while helping solve existing ones, and help explain the perspective on commonisation and decommonisation. Both commonisation and decommonisation are continuous and potentially two-way, meaning that they can act to hinder each other by influencing the social, economic, ecological, political, historical and cultural aspects of an area. The resource can enter a process of commonisation; already-established commons or resources that are being commonised could also revert to decommonisation (Nayak and Berkes, 2011). Commonisation and decommonisation are useful lenses through which to analyze the two faces of aquaculture.

From a commonisation view, collectively managed resources work better than totally government-managed or privately managed resources; collective action is an effective means of confronting commons problems (Ostrom et al., 1999, Ostrom, 2007, Galappaththi and Berkes, 2014, Ostrom, 2014, Galappaththi and Berkes, 2015a). Galappaththi (2013) applied this approach to understand small-scale community-based aquaculture in Northwestern Sri Lanka. His findings suggest that large-scale aquaculture makes high returns on investment during the first few years, with the expectation that the shrimp farmers abandon their farming areas, move to new areas, and set up farms rather than establish sustainable practices and remain in one area. In contrast, small-scale community-based aquaculture farmers do not have the option of relocating. They cannot afford to act in unsustainable ways, as they are accountable to the community in which they live and do not have huge investment capacity (Galappaththi and Berkes, 2014, 2015a). Furthermore, Marschke et al. (2012) highlight how commons thinking can influence fisheries management including aquaculture.

In the context of decommonisation, aquaculture often involves the enclosure and privatization of resources — known characteristics of most neoliberal environments (Peluso, 2007). Belton et al. (2011) highlight the social implications of the enclosure and privatization of resources in Bangladesh; these resources were previously managed under common-property aquaculture regimes. Huong and Berkes (2011) examine how rapid development of aquaculture in Tam Giang Lagoon, Vietnam promoted privatization and reduced available lagoon water area for mobile-gear small-scale fishers. Nayak and Berkes (2011) report that approximately 60% of Chilika Lagoon remains under shrimp aquaculture (an activity declared illegal by the Supreme Court of India). The area for shrimp aquaculture comes from the forced encroachment of former commons under the control of small-scale fishers now held under elite capture (Béné, 2003, Nayak and Berkes, 2010), a situation akin to de facto privatization where higher caste, economically powerful, and political strong people have taken control of the fishing area. Enclosure and privatization in aquaculture are two of the main factors causing decommonisation. Globally, there are widespread examples of aquaculture contributing to the breakdown of customary commons institutions that were in charge of fishery management (Dewalt et al., 1996, Nayak and Berkes, 2010, Huong and Berkes, 2011, Nayak and Berkes, 2011, Benessaiah and Sengupta, 2014).

Consequently, the two faces of shrimp aquaculture, with its commonising and decommonising effects, create a conundrum that requires scholarly attention. While the bulk of the fisheries literature supports the idea that unregulated aquaculture can cause decommonisation (Pradhan and Flaherty, 2007, Nayak and Berkes, 2011, Benessaiah and Sengupta, 2014, Galappaththi and Berkes, 2015a), only a handful of studies suggests that there can be positive outcomes with large-scale aquaculture acknowledging their direct contribution to national economy (Nielsen et al., 2016). There are no straightforward “yes” or “no” answers to these assertions. Aquaculture can cause both commonisation and decommonisation; however, the scale at which their outcomes and impacts are felt is significant. While aquaculture’s decommonising effects are undesirable from the ecosystem and human wellbeing perspective (Nayak and Berkes, 2010, Nayak and Berkes, 2011), positive outcomes associated with a process of aquaculture-led commonisation are desirable (Galappaththi and Berkes, 2015a). However, the former remains a well-studied area of fisheries research, while there has been little or no published literature on aquaculture’s potential as a factor of commonisation. We acknowledge there are documented evidence for different forms of commonisation in fisheries (Sundström, 2013, Foley and McCay, 2014, Oviedo and Bursztyn, 2016), but so far not clearly in aquaculture, particularly in shrimp aquaculture except the unique Sri Lanka case study (Galappaththi and Berkes, 2015a, 2015b). Using commonisation and decommonisation as the two faces of aquaculture, we aim to address this gap in the literature. We use two cases — aquaculture-led privatization in the Bay of Bengal area of India and collective action around shrimp aquaculture in Northwestern Sri Lanka — to assess the potential of small-scale shrimp aquaculture for social-ecological sustainability and empowerment.

Methods

Both case studies result from a mix of qualitative, participatory, and collaborative approaches (Johnson and Onwuegbuzie, 2004, Creswell, 2013). The Chilika case study is an ongoing longitudinal study since 2007 that focuses on the processes of social-ecological change and their drivers in Chilika Lagoon, Bay of Bengal, India (Fig. 1). The Sri Lankan case study was a combination of two projects focused on value chains of shrimp aquaculture and governance of small-scale shrimp aquaculture that were conducted during 2007 to 2009 and then from 2012 to 2014, respectively. Both studies were based on data collection methods such as semi-structured interviews, participant observations, focus group discussions and meetings. The history of shrimp aquaculture in Chilika was explored through interactions with village elders, some of whom were actively involved in fish cooperatives and the federation. In the Sri Lankan case, key informant interviews with founders of the present management system, cooperative leaders, village elders, and government officials were conducted to gather historical data. Both studies were supplemented by the secondary data gathered from written records of shrimp farmers’ associations and published government documents including government orders, development plans, legislative proceedings, and other policies concerning lagoon management at all levels of the district, state, and nation. Methodologically, the two case studies were mainly chosen because of compatibility in data collection approach and close time frame (2007-2014) that both studies were conducted.

Fig. 1
figure 1

Study areas in Sri Lanka and India

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Results

Case study one: aquaculture-led privatization in India

Chilika Lagoon is one of the largest lagoons in India and Asia, with an area of 1165 km2. Chilika is located in Odisha State on the east coast of India on the Bay of Bengal. Chilika is a globally important Ramsar site and a productive area with fish fauna adapted to a mix of seawater and freshwater. The shallow and sheltered waters of Chilika are appropriate for aquaculture, particularly for commercial production of tiger prawn (Penaeus monodon). A biodiversity hotspot, Chilika boasts a rare mix of estuarine, marine, and freshwater ecosystems.

Besides being a productive ecosystem, Chilika is known for its rich fishery resources. More than 400,000 fishers, representing seven fisher castes and their sub-castes (who are considered occupying the lower ranks in Hindu caste hierarchy), customarily managed the lagoon resources as commons and depended upon it for their livelihoods. The dominant fishing regime was capture fishery, and its management as commons was facilitated through village-level institutions. Fish cooperative and village committees, as well as regional-level fisher organisations (Chilika Machyajibi Mahasnagha or the fisher federations) are supported by locally crafted and agreed-upon use and management rules. The fishers in Chilika are caste-based. The vocation of traditional fisher groups is identified by their membership in certain Hindu castes. These fishers live in approximately 150 villages in and around Chilika. The lagoon ecosystem also supports a number of non-fisher village communities in the watershed area. These non-fisher communities engage in cultivation, depend on forests, and undertake other non-fishing occupations for their livelihoods. However, owing to large-scale forest degradation and the fact that land is not suitable for paddy cultivation, subsistence based on agriculture and forests is decreasing. Many non-fishers have turned to fishing, mainly aquaculture, as a source of income.

Since the 1970s, a boost in global fish demand and the shrinkage of total yield from capture fishery sources have brought aquaculture to the forefront and promoted the development of an international market for shrimp and prawn (Marshall, 2001, Delgado et al., 2003, Pradhan and Flaherty, 2007). Shrimp in India that had little value previously became “pink gold” (Kurien, 1991) and gained momentum through intensive aquaculture (Tovar et al., 2000) in the mid-1980s, putting India among the leading shrimp-exporting countries in the world. Chilika Lagoon was a natural area for tiger shrimp and caught on to the trend in the early 1980s. Investors and policymakers found it highly suitable for shrimp aquaculture.

As the international price of tiger shrimp tended upward, shrimp aquaculture became a major driver of change in Chilika Lagoon. Its development spread with great speed and intensity. Of a total of 140 fisher villages surveyed in 2009, 135 stated that they were adversely affected by shrimp aquaculture in Chilika. In the fishers’ own words, “the onset of shrimp aquaculture in Chilika pushed us from the sky to beneath bare ground [Chingudi Chasa aamaku akasaaru patalaku theli dela]”. The caste-based fishery commons received several impacts from aquaculture in Chilika.

Soon, an emergent culture of encroachment developed. Non-fishers (who are higher up in the Hindu caste hierarchy) and some fishers were supported by elites in the bureaucracy and political circles took up large-scale profit-driven aquaculture. In the process of encroachment, they took over customary capture fishery commons that were controlled by caste-based fishers and turned these into shrimp farms. The fishers soon found that the lagoon was virtually taken over by non-fishers and the “shrimp mafia.” The study documented this claim by showing the encroachment on customary fishing areas in 91% of the lease-holding fisher villages of Chilika. There were many impacts of shrimp aquaculture on the social-ecological system of the lagoon (Table 1).

Table 1 Various impacts of shrimp aquaculture in Chilika Lagoon
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Significant changes in earlier government approach adapted to the management of Chilika Lagoon. Policy support for the caste-based capture fishery was withdrawn in support of the aquaculture-based fishery and the extension of rights to non-fishers. The state government introduced a new policy in 1991 which became a landmark piece of legislation because it created culture sources of fisheries in Chilika and, in addition to the customary capture practices of the caste-based fishers, legalized shrimp aquaculture. The legislation also made provisions for non-fisher caste villages to engage in aquaculture. In accordance, 6000 ha of customary fishing commons were withdrawn from caste-based fishers and reallocated to non-caste fishing villages. This loss of customary fishing areas by fisher villages was in addition to the area already under encroachment by the powerful shrimp mafia. The government even moved to bring in “holding companies” like the Tata Company to take up intensive shrimp aquaculture in Chilika.

Because of prolonged legal battles including fisher cooperatives’ legal action against the 1991 policy in the Odisha State High Court, in 1993 shrimp aquaculture was banned by the Odisha State High Court. Further, shrimp aquaculture was banned by the Supreme Court of India in 1996 and the Odisha State Legislative Assembly House Committee in 1997, upholding the customary rights of caste-based fishers in Chilika. Finally, in 2001, the state government banned shrimp aquaculture in the lagoon and canceled the 1991 lease policy. However, in Chilika, such court decisions did not have much impact on the ground, as illegal shrimp aquaculture continued unabated as of 2014. According to conservative estimates, more than 60% of the lagoon fishing area remains under illegal shrimp aquaculture; according to other reports the figure is closer to 80% (Nayak and Berkes, 2010). Village fishing areas that were used as caste-based commons have essentially become “privatized” (Nayak and Berkes, 2010). The gap between higher court rulings and their implementation stems from the lack of accountability in implementing institutions, and showcases the clout of capitalist forces within the ruling class in Odisha. These developments have led to issues regarding fishers’ access and entitlements. Aquaculture has also led to a steady erosion of institutions managing fishery commons in Chilika. With the loss of fish resources, most village fisher cooperatives went out of business.

Case study two: collective action around shrimp aquaculture in Sri Lanka

Tiger shrimp farming is the dominant coastal aquaculture operation in Sri Lanka; however, it is mostly restricted to the coastal Northwestern province and is inconsistently practiced in the eastern part of the country, mainly due to civil war (1980s to 2009) and the 2004 tsunami. As Fig. 1 shows, Northwestern shrimp aquaculture predominantly occurs in lagoon-based water systems. Puttalam Lagoon (32,000 ha), Mundal Lagoon (3600 ha) and Chilaw Lagoon (700 ha) are the three main lagoons in this part of the country (Pathirana et al., 2008). These three lagoons and other small bodies of water in the area are connected by a human-made Dutch canal, forming an interconnected common body of water. The Sri Lankan case study focuses on 32 lagoon-based coastal communities. These are small-scale shrimp farming communities, and a high level of family involvement (owner-managed) is consistent across them. Galappaththi (2013: 123-127) illustrates more information about scale of shrimp farming and nature of operations. Apart from shrimp farming, the most common livelihood activities are small craft fishing, cast net fishing, shrimp breeding, paddy farming, and coconut cultivation.

Shrimp aquaculture in Northwestern Sri Lanka started in the late 1970s with four large-scale multi-national companies with no government involvement. Because of the attractive profit margins, local people who were employed at these large firms started their own shrimp farms, applying the experience they had gained from employment with the shrimp companies. By the 1990s, a mix of large-, medium-, and small-scale shrimp farms became visible in the Northwestern region, with a total of about 1500 farms. Large-scale shrimp operations shifted from place to place through the conversion of mangrove areas (Gunawardena and Rowan, 2005) and coconut cultivation lands into shrimp farms (Cattermoul and Devendra, 2002). Disease outbreaks between 1988 and 1998 heavily impacted the shrimp industry in Sri Lanka. There were three major outbreaks: the Monodon Baculo Virus in 1988 and 1989, the White Spot Syndrome Virus (WSSV) in 1996 and both WSSV and the Yellow Head Virus in 1998. WSSV can kill shrimp within 24 h, and spreads rapidly through the use of other aquatic animals (crustaceans, birds) as carriers. Because of the interconnected nature of the common body of water (the Dutch canal connecting all three lagoons) and the dependency of shrimp farmers on this body of water, shrimp diseases transmitted rapidly. Large-scale and most medium-scale farming operations went bankrupt, and small-scale shrimp producers struggled for survival (Galappaththi and Berkes, 2014).

During the 1990s, community-based institutions (shrimp farmers’ associations) emerged at the village level to collectively respond to common challenges, such as drastic price fluctuations due to the impacts of disease outbreaks, as well as non-disease related factors including inflation. All shrimp farmers are represented by community-based institutions known as shrimp farmers’ associations (“Samithi” in the Sinhala language). Any individual within the community interested in undertaking shrimp farming must become a member of the shrimp farmers’ association. The association collectively owns all potential areas for shrimp farming. It grants permission and makes area allocations to individuals for shrimp farming. Each association has its own rules to restrict new or potential shrimp farmers from farming in a community. For example, one rule is that newcomers must attend community association meetings continuously for six months before they are eligible for membership. Members are not allowed to sublease or rent their farms without the consent of the association. Galappaththi and Berkes (2014) discuss more about how shrimp farmers associations developed over time and about multi-level commons institutions.

In 2003 and 2004, however, a significant system change in resource management took place due to the introduction of increased government control of shrimp-aquaculture-related resource use. This change was a result of a collaborative effort on the part of shrimp farmers’ associations and shrimp breeders’ associations. During this period, shrimp farmers established a national-level shrimp aquaculture sector association known as the SLADA (Sri Lanka Aquaculture Development Association). They also requested that the Central Government (Ministry of Fisheries) assign a separate institution to monitor and support the shrimp aquaculture industry in their implementation of an action plan called the “Zonal Crop Calendar System.” As a result, NAQDA (National Aquaculture Development Authority) became the main government institution responsible for the shrimp aquaculture sector and a North-Western Shrimp Aquaculture Monitoring Unit was established to facilitate the implementation of the action plan.

The primary objective of the Zonal Crop Calendar System was to manage shrimp disease. Because the spread of disease was linked to the common body of water (or the linkages between the lagoons through the Dutch canal), the Northwestern shrimp farming area was divided into five zones and 32 sub-zones. This zonal system was used to collectively decide who or which area (i.e., zone/sub-zone) could access the shared body of water at a stipulated time. A schedule/timetable (known as a crop calendar) was designed to manage communities’ access to the common body of water. The crop calendar was developed on an annual basis with the participation of all stakeholders in the shrimp industry. This created opportunities for collective action in the area where collaborative processes facilitated meaningful negotiations amongst farmers and resulted in the effective resolution of conflicts. Using the crop calendar, shrimp farmers worked collaboratively and collectively, instead of competing, to overcome challenges.

In 2012 and 2013, there were about 600 shrimp farms in the Northwestern area, all of which depended on water from the lagoon-based interconnected body of water. Since there are collective rules and appropriate institutional arrangements in place, this body of water acts as a commons. Each shrimp farmers’ association, with the support of government extension officers, monitors and enforces the rules that control pond water discharge. This monitoring is an ongoing process throughout the culture cycle. Discharge of used pond water is a major problem, as farmers release disease-infected water from shrimp ponds into the surrounding environment through the interconnected body of water. This individual action affects the ability of other shrimp farmers to continue farming without fear of disease. For example, if a particular farm is infected with diseases at the latter phase of production, the rational behavior of the cultivator is to harvest the infected pond before the quality of shrimp degrades, in order to make a better return on investment. However, if this farmer releases contaminated pond water to the common body of water, there is a high possibility of the disease spreading into other farms, which may not survive the disease (Galappaththi and Berkes, 2014, 2015a).

As of 2016, Sri Lankan Northwestern shrimp aquaculture remains a small-scale operation managed collaboratively through a mixed commons regime, i.e., private, communal and government ownership (Galappaththi and Berkes, 2015a). In the present arrangement, even privately owned or family-owned shrimp farms are managed under community rules. Lagoon-based capture fisheries still exists in Northwestern Sri Lanka, but not under shrimp aquaculture management regime (outside of the communal management institutions). The heart of this community-based shrimp aquaculture management system is a multi-layered structure of commons institutions (Galappaththi and Berkes, 2014) (Table 2). First, bottom-level sub-zones (usually communities) are represented by community associations which handle the regulation of routine shrimp farming activities. Second, these sub-zones aggregate into zones, forming zonal-level associations comprised of the leaders of sub-zonal associations. Their responsibility is to improve the infrastructure (roads, transportation, electricity supply) required for shrimp farming by working with divisional-level government authorities. Third, SLADA, as represented by the leaders of the zonal/sub-zonal associations, is responsible for the development of shrimp aquaculture in the area. Overall, SLADA closely collaborates with NAQDA in decision making. Effectiveness of this resource management system is partly reflected by the incremental growth of national shrimp aquaculture production since 2005, when the Zonal Crop Calendar System was first established (NAQDA, 2017).

Table 2 Multi-layered structure of commons institutions
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Discussion and conclusions

Decommonisation in the context of shrimp aquaculture is globally widespread. In this context, aquaculture is usually seen as a driving factor of adverse environmental and social changes (Nayak and Berkes, 2011, D'Anna and Murray, 2015, Kassam and Dorward, 2017). The global shrimp trade (and the influential and lucrative international market price) combined with implementation of neoliberal approaches has remained a key driver of shrimp aquaculture since the late 1980s. Thus, from an economic perspective, shrimp aquaculture is an attractive profit-making opportunity for entrepreneurs. Nonetheless, the economic prosperity achieved through shrimp aquaculture comes at immense environmental, social, and institutional costs. While we know much about the adverse impacts of shrimp aquaculture and its role in causing various forms of decommonisation, examples of commonisation as it pertains to aquaculture are rare and constitute a less-explored area within small-scale fisheries literature (Galappaththi and Berkes, 2015b).

We argue, from a commons perspective, that aquaculture as a driver can cause both commonisation and decommonisation. Commonisation can occur when the process of farmers cooperate with each other by working collaboratively and collectively using commons institutions instead of competing, to solve commons problems. Our Sri Lankan case study provides an example of commonisation, i.e., how aquaculture farmers regulate themselves under a commons arrangement (e.g., collective action, and institutional and rule systems) to overcome challenges such as diseases, water distribution, pollution, conflict resolution and external linkages including policy and market. However, our Chilika case study depicts a process of decommonisation, i.e., how aquaculture triggers the disintegration of existing institutional, economic, social and cultural arrangements surrounding customary fishery commons. Here, aquaculture-led decommonisation took shape through the synergistic impacts of multiple factors such as global market trends, the global shrimp price, the creation of protected (restricted-access) areas, a change in government policy, a culture of encroachment, the erosion of fisher institutions and a change in fishing practices (Nayak and Berkes, 2010, 2011).

Aquaculture can make new (aquaculture) commons or break existing (fishery) commons (the two faces) by acting as a driver for both commonisation and decommonisation. In the case of Chilika Lagoon, fisheries have moved from being under a commons regime to an active phase of decommonisation. The situation is the opposite in Northwestern Sri Lanka, where decommonisation in the shape of privately owned large-scale aquaculture operations has given way to small-scale collective-action-oriented shrimp aquaculture that characterises a process of active commonisation. This resilient shrimp aquaculture governance system (mix regime; multi-level structure; robust community control using Samithi rules) make less feasible the occurrence of simultaneous (de)commonisation process in the same shrimp aquaculture management area (Galappaththi et al., 2017). Our cases together represent the two faces of shrimp aquaculture and critical insights into the role of shrimp aquaculture in achieving social-ecological systems sustainability (Berkes et al., 2003, Folke, 2016).

The commonisation process in Northwestern Sri Lanka is driven by multiple factors (Table 3). The zonal crop calendar system coordinates the discharge of pond wastewater. This mechanism is coordinated by the shrimp farmers’ associations together with government institutions. The multi-level institutional structure of shrimp farmers’ associations is collaboratively working with the government in decision making related to shrimp aquaculture management. A bottom-up management approach with government support is the distinguishing functional feature of this integrated institutional structure. A built-in financial and non-financial incentive for membership is a motivational driver for stewardship. Shrimp farmers develop this multi-level commons management system in cooperation with the government to effectively manage aquaculture CPR — an interconnected lagoon body of water. Sri Lankan small-scale shrimp aquaculture is run by the mixed commons regimes of private, communal and government (Galappaththi and Berkes, 2015a). An amalgamation of these factors makes a unique resource management system: aquaculture commons.

Table 3 Shrimp aquaculture-related factors contributing to the process of commonisation in Northwestern Sri Lanka
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In reverse, the Chilika case offers insights into decommonisation led by a series of factors associated with shrimp aquaculture (Table 4). The overall change in the lagoon was characterized by a move from customary, community-based capture fishing to large-scale, individually owned shrimp aquaculture operations. As a direct consequence of shrimp aquaculture-led encroachments, the lagoon witnessed an extensive loss of fishers’ access and entitlement rights (see Table 1 above). There was a breakdown of multi-level fishery institutions (e.g., village cooperatives, the fisher federation, the regional fish marketing federation) and collective decision-making arrangements. Influenced by rampant shrimp aquaculture, these changes became direct drivers of decommonisation. State policy changes in favour of shrimp aquaculture, caste politics (e.g., fishers and non-fishers based on their position in the Hindu caste hierarchy) and growing resource conflicts pushed the ongoing processes of decommonisation. This has resulted in the occupational displacement of customary fishers and out-migration by more than one-third adult fishers. On the ecological front, shrimp aquaculture had a deleterious effect on the biophysical, hydrological and geochemical processes of the lagoon, not only challenging its long-term sustainability but also jeopardizing its status as a commons (e.g., a commons does not exist if there is no physical resource present). Thus, a combination of these factors provides evidence of the possibility of shrimp aquaculture-led decommonisation.

Table 4 Shrimp aquaculture-led factors contributing to the process of decommonisation in Chilika Lagoon, India
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Table 3 and Table 4 provide a baseline for understanding commonisation and decommonisation in the context of shrimp aquaculture. However, the list is not fully inclusive, as several other factors may result in similar experiences. Nonetheless, Table 3 offers a hopeful message for the future of aquaculture so long as certain conditions are met. We recognize that the successes of aquaculture (e.g., unregulated, large-scale/industrial, profit/export market-driven kind) can come at significant social and environmental costs. Given this reality, the message in Table 4 is no less significant as it offers a set of factors that are better avoided, as they promote decommonisation. We suggest that both Table 3 and Table 4 teach a key strategy, i.e., to capitalize on the factors of commonisation in Table 3 to tackle the factors of decommonisation in Table 4. How we can best implement this depends on the social-ecological and political contexts within which shrimp aquaculture is practiced. For example, in Northwestern Sri Lanka, small-scale shrimp farmers are empowered by their experience working for large-scale aquaculture companies (a failed example due to the effects of decommonisation). If the big companies had continued their operations, the Sri Lankan case would have produced far greater decommonising effects on the small-scale customary fishery commons in the Puttalam, Mundal, and Chilaw lagoons. Using this case study, we argue that lessons learnt from aquaculture-led decommonisation in a particular social-ecological context (e.g., Chilika Lagoon, Bay of Bengal, India) can be used to promote a process of commonisation.

Turning a process of decommonisation into commonisation involves questions about issues regarding excludability and subtractability. “Tragedy of the commons” (Hardin, 1968) describes how freedom to access the commons can cause the whole system to fail (Feeny et al., 1990, Ostrom et al., 1999, Poteete et al., 2010, Battersby, 2017). In an aquaculture context, this tragedy takes shape through the loss of fishers’ customary access to control by powerful external actors whose exclusion becomes tricky (an excludability concern), and their hostile actions around reshuffling rules of resource (mis)use, (re)distribution, (re)allocation and (over)exploitation reduce resource availability for the customary fishers (a subtractability concern). In our case study contexts, a similar tragedy became evident due to the overuse of environmental resources as inputs and the discharge of wastewater into the environment by industrial aquaculture groups in Northwestern Sri Lanka (Bournazel et al., 2015, Harkes et al., 2015) and the encroachment of customary capture fishery commons by groups of higher caste non-fishers and regulation of the use of the lagoon space in Chilika Lagoon, India (Nayak and Berkes, 2011). Solving this “tragedy” should start by fixing the excludability and subtractability problems in novel ways (Feeny et al., 1990, Ostrom, 1990, Ostrom et al., 1999, Nayak and Berkes, 2011, Galappaththi and Berkes, 2015a). For example, in the Sri Lankan case, fixing the excludability and subtractability problems meant transferring the power to control resource access back to the small-scale shrimp farmers and strengthening their capacity to formulate and enforce rules of subtraction, exclusion and inclusion. However, such a shift has yet to take place in Chilika Lagoon. Consequently, the aquaculture tragedy, in the form of subtractability and excludability problems, remains unresolved here.

Collaboration, cooperation, and collective action are essential elements of successful commons management (Poteete et al., 2010). However, collaboration over competition, and cooperation over contestation, are not easy to achieve without engaging in processes of negotiation, partnership, relationship and institutional linkages across multiple levels. Sri Lankan shrimp aquaculture provides evidence of transforming from aquaculture as a competitive and highly contested game to it being a collaborative and collective action-oriented game. For example, the community association is the fundamental institution that promotes collective action at the bottom (sub-zonal) level. At zonal and national levels, the multi-layered institutional structure works as a mechanism for collective action. This demonstrates the fact that aquaculture has the potential to create collective action and commons institutions if played using the rules of collective action (De Silva and Davy, 2010, Galappaththi and Berkes, 2015b). Otherwise, it creates environmental injustice with grossly decommonising effects (Nayak and Berkes, 2010, 2011).

Summing up: possible way forward

Given the threats and opportunities, the two faces of shrimp aquaculture warrant further scholarly attention. This will include an examination of conditions that promote aquaculture-led commonisation and possible ways of addressing the key factors that create opportunities for decommonisation. In particular, there is an urgent need to expand on case examples.

Our case analysis offers two alternate scenarios. Scenario one suggests that, if implemented judiciously, a combination of small-scale and non-intensive aquaculture and capture fisheries within a commons framework has tremendous social-ecological potential, as in the case of Northwestern Sri Lanka. First, it helps to avoid such ecologically damaging activities as the conversion of mangrove and coconut cultivation areas into shrimp ponds and the contamination of wetland habitats with disease and pollution, and their resulting environmental consequences. Second, it creates economic opportunities for a large number of individuals and families to engage in income-generating operations instead of having benefits flow to only a handful of households that have investment capacity. Third, this practice is known to be socially acceptable and culturally appropriate because it is rooted in local history, customs and practices. In addition to making social and cultural sense, it is more equitable in comparison to large-scale individually owned aquaculture systems. Forth, a commons framework for including aquaculture in fisheries governance is politically empowering as it creates opportunity and space for everyone involved to participate in the institutional and decision making processes. Through this route, aquaculture can potentially strengthen processes of commonisation in the governance of local fisheries instead of disrupting existing institutional processes through decommonisation.

In scenario two, unabated, large-scale and intensive aquaculture that aims to replace customary capture fishery systems already in place will be detrimental to the entire social-ecological system, as seen in the case of Chilika. First, ecological consequences will include conversion of multi-species and biodiverse ecosystems into monoculture environments with alterations in biophysical, hydrological and geochemical processes. Second, local capture fishery-based economic and livelihood systems will collapse into market-driven, externally influenced and out-migration dependent systems. The small-scale fishers will suffer the consequences of poverty and food insecurity, making them further vulnerable to marginalisation. Third, rife with inequity and negative power dynamics, it will contribute to growing contestations, conflicts and loss of community cohesion and cooperation, resulting in the local fishery losing its social and cultural identity. Forth, local fisheries governance systems will give way to a combination of centralized top-down state management and de facto privatization through the “elite capture” of customary fishing grounds (Nayak and Berkes, 2010), resulting in political disempowerment of small-scale fishers and their exclusion from decision making processes. Overall, this scenario implies that such aquaculture practices will cause an accelerated process of decommonisation of local fishery commons.

The two scenarios offer further insights into the initial depiction of the two faces of aquaculture. One scenario suggests the possibility of both aquaculture and capture fishery working together in tandem within a commons approach for social-ecological sustainability, whereas the other rests on the principle of exclusion whereby aquaculture thrives by displacing small-scale fishery systems that are already in place. How, then, do we minimize the decommonising effects and promote the commonising impacts of shrimp aquaculture? To do this, a series of policy provisions, awareness-building measures, management and governance innovations, institutional arrangements, rules and norms, and multi-level negotiations will be required. Feasibility of two scenarios will open avenues for more policy related research opportunities on shrimp aquaculture.

Following Nayak and Berkes (2010), we extend the argument that aquaculture has the potential to enhance social-ecological processes and their outcomes if played as a win-win game that respects local rights and livelihoods, as well as ecosystem processes. Or it can be played as a win-lose game that creates environmental injustice and processes of social-ecological marginalisation. As a win-win game, aquaculture will become a driver of commonisation, as in the case of Northwestern Sri Lanka. Conversely, it will act as a driver of decommonisation when played as a win-lose game, as in the case of the Bay of Bengal, Chilika Lagoon, India. Transitioning from “aquaculture as a zero-sum game” to “a win-win game” will depend largely on how effectively we strike a balance between the two mutually exclusive faces of aquaculture — commonisation and decommonisation. The challenge, then, is to assess how, and if, key lessons from aquaculture’s role in the commonisation processes in Sri Lanka (and similar cases elsewhere) can be implemented to reverse processes of decommonisation elsewhere, such as the case of Bay of Bengal, Chilika Lagoon, India.