When the oceans are plundered
The nineties may well be remembered as the decade that the crisis in world fishing first hit. For the 200 million people, mainly from developing countries, who depend on diverse thriving aquatic ecosystems for their livelihoods, the consequences have been most severe. Since the fifties the world's fishing fleet has been growing, reaching a peak between 1970 and 1989 when fleets grew at twice the rate of fish landings. Corporate-ridden and stimulated by international development agencies and banks, the industrialisation of fisheries and the race for the last fish, have led to global problems of over-capacity and over-investment. Each year, the governments of the world subsidise the global fleet by US$54 billion to obtain catches to the value of US$79 billion. Ever more sophisticated technology is carried by larger vessels and bigger fleets producing more waste. The United Nations Food and Agriculture Organisation (FAO), has calculated that close to one fifth of the world's marine fish catches are discarded back into the sea.
As fish become scarcer, prices increase and the international fish market expands to new grounds. Fish production in the Southern countries has skyrocketed with foreign exchange earnings from their fish increasing from US$9 billion in 1983 to US$17 billion in 1993. While both States and small-scale fishermen in the South may temporally benefit from higher prices, the poor and the not-so poor consumers in the South gradually lose their access to a traditionally cheap protein, as fish literally travels North, either by boat or plane. Exports increase more than production and internal fish consumption decreases. In the period 1978-1988, African per capita supply decreased by 2.9% and in South America by 7.9%, while fish has become expensive even for middle classes in India. The average fish consumption in the North is triple that of the South, even though fish constitutes a more important part of the diet in many areas in the South, particularly Asia. For example, in Bangladesh, where fish accounts for more than 50% of the animal protein intake, the average annual per capita intake is 7.2 kilograms. In contrast to the United Kingdom and United States, where fish accounts respectively for some 10% and 6% of the animal protein intake, annual per capita consumption is close to 20 kilograms. In the long term, both North and South, the intensification of fishing activities results in small-scale, inshore fishermen being pushed aside.
Although global fish catches have steadily increased since the fifties, up to the 116 million tons produced in 1996, there are numerous signs that this trend is unsustainable. According to the FAO, in 1994 35% of fishing grounds were over-exploited or depleted, while 25% were fully exploited and only 40% allowed for an increase in captures under current exploitation patterns. As the FAO itself puts it, "the ever-growing total tonnage of world fishery production gives a misleading vision of the state of world fishery resources and a false sense of security".
There is no shortage of indications that something fishy is indeed happening to our oceans. Just a couple of examples may help to give an idea of the depth of the problem. World-wide, only the Western Pacific still keeps healthy tuna resources, while Greenpeace reports that, "Scientists estimate that overfishing has reduced Southern bluefin to only 2-5% of its original population levels". Almost all groundfish stocks seem to be heavily fished or overfished in just ten years, the world catch of groundfish species has been halved. It had traditionally been considered that the likelihood of fishing any species to extinction was remote. Nevertheless, in 1996 the IUCN included about a hundred species of marine fish in their Red List of endangered species. Besides several species of tuna, it includes sharks and more than 30 species of seahorse.
The evidence is so large, and the implications so deep (not only for the world's peoples, but also for the fish processing industry) that the problem has now been widely acknowledged. However, more than stressing the need to change fishing strategy, those who created the problem in the first place, such as the World Bank, UN FAO and the agri-food industry, are keen to promote aquaculture as a new industrial sector. In the words of Ismael Serageldin, Chair of the Consultative Group on International Agricultural Research (CGIAR): "On the land we have learned to produce food by cultivation. But in the sea we still act as hunters and gatherers". To raise the sense of urgency, we are again reminded about the need to feed a growing world population. The FAO projects that by 2010 there will be a shortfall of 16 million tons in the supply of fish and fishery products to meet demand. As the North Atlantic Salmon Conservation Organisation (NASCO) says, "By the year 2025 the demand will have increased from 100 to 165 million tons". The crisis is also recognised by industry as mentioned by Aquaculture Production Technology, a specialised Israeli company, "The only way to bridge the gap between reduced capture fisheries output and increased world demand is through Aquaculture". A closer look at the proposed solution of aquaculture raises doubts as to its long term viability. It is noticeable that to convince society of the importance of learning to cultivate fish, the promoters of aquaculture have their best arguments in the experience of farming communities world-wide who have been doing it for millennia.
Traditional, extensive aquaculture
The harvest of wild fish and other aquatic produce such as crabs and frogs, collected from rice paddies after the first heavy rains, continues to be key for food security and animal protein intake to many farming communities in lowland areas of Asia. Aquaculture, however, starts when human action controls or enhances the rearing in water of fish, crustaceans or molluscs. The rise of carp within complex agricultural rice systems in China is perhaps as old as rice culture itself. Rice farmers in Kerala, India, have for centuries managed a polyculture system based on rotational cultivation of rice and shrimp, their Chenmmeenkettu. Equally, 300 years ago the Japanese learnt to favour the growing of seaweed for their diet.
These low-external input aquacultural systems, which are often referred to as "extensive aquaculture" by the formal sector, do not compete with other uses of the aquatic environment, but rather complement them by helping to close nutrient cycles. For example, in many countries, particularly in Asia, farmers have developed systems in which wastes - poultry, animal and plant wastes - are thrown into fishponds to encourage the growth of organisms which fish feed upon. Wastes are then returned to the field as fertiliser. The main fish species in these systems are carp and, more recently, tilapia. These systems still thrive today through local initiative and NGO rural development programmes. Rice farmers are continuously adapting fish to their needs such as pest and weed control.
Farmers innovation has helped enhance nutrition and increased their income. In Indonesia, fish can help raise incomes from paddies because fish income does not have to be shared with the landlord. The results of the introduction of fish in complex agricultural systems may be spectacular even from a purely economic point of view. Malawian farmers have been able to totally transform their farm management through fish aquaculture in the marginal wet lands, associated with vegetable cropping. After seven years these farmers came to earn more from the gardens and ponds than from their croplands and homestead, and it has been calculated that for every dollar invested in the wetlands seven were generated. The importance of such aquaculture for food security is reflected in the fact that 85% of aquacultural production in the South is consumed locally.
The Blue Revolutionaries
The new prophets of aquaculture intend to reproduce the Green Revolution production model in aquatics. Industry, multilateral development banks and UN agencies proclaim it as the Blue Revolution. Although occasionally referring to the benefits of traditional aquacultural practices, what they propose is entirely different: the monocropping of high-value species to supply international markets. Will a model based on the green revolution, that failed to meet the needs of the resource poor and increased genetic erosion in agriculture, do any better underwater?
Half of marine aquacultural production is actually made up of marine algae and seaweed, mainly kelp, this article focuses exclusively on the fish sector. In the last ten years aquacultural production has more than doubled, to one fifth of total world fish production (figure 1). Given that one third of all fish catches are turned into fishoil and fishmeal, aquaculture provides a quarter of the fish used for direct human consumption. Impressive as this growth may look, it reflects mostly the activity of a single country, China (see box & figure 2).
Asian developing countries provide the centre of production and in 1995, China alone accounted for 63% of total world aquaculture. The other main producers are: India, the Philippines, Indonesia, Thailand, Bangladesh and Taiwan. Within developed countries, Japan and the US are the main producers, followed by France, Italy and Norway.
The species produced vary according to the kind of water and to the regions (table 1). World-wide, the bulk of the production is still from low-value freshwater species that are raised in integrated agricultural systems: carp and, to a lesser extend, tilapia. The farming of this latter species has recently expanded very quickly in Asia and Africa. In 1992 world-wide production of tilapia reached 473,000 tonnes, mainly from China, Indonesia, the Philippines and Egypt. The production of various carp species is higher still. In 1995 world-wide production of the silver, grass and common carp was 6.7 million tons. Although carp are also important in some European countries, particularly Hungary, developed countries tend to cultivate more added-value fish in their freshwaters. In the US, the main species is catfish, while trout are appreciated in the US, Europe and Japan.
Brackish waters, a mixture of sweet and marine water with intermediate salinity, are found in such places as mangroves, estuaries, lagoons and swamps. They account for 7.1% of fish aquacultural output, centred on high-value species. In developing countries, there has been a wide expansion of export-oriented shrimp aquaculture, while in European Mediterranean countries these areas hold the production of oyster and high-valued carnivorous marine finfish species such as stripped seabream and seabass. If traditional integrated aquaculture activities in Asia are left aside, in the North and South aquaculture is focused on high value species (molluscs, crustaceans, marine fish and salmon) that together account for 31.5% of world production equal to 61% of the total market value. It is these areas where the promoters of the Blue Revolution have invested their resources.
Towards aquatic monocultures
The most serious impact of the blue revolution aquaculture is that, rather than increasing global catches, it may very well lead to lower total productivity of our seas. Most intensive aquacultural operations take place in shallow waters which compete with other possible uses. Plentiful sunlight and nutrients in these zones, contribute to the position of shallows as the world's most diverse and productive types of marine ecosystems, including seagrasses in temperate zones and mangroves and coral reefs in tropical areas. Such systems harbour the juvenile stages of most fish species, including the oceanic fish which sustain both traditional and industrialised fishing activities.
The intensive, high-density cultivation of fish and shellfish has environmental effects similar to those of intensive livestock or poultry. First and most evident is the accumulation of organic matter, both in the form of unconsumed feed and faeces. When aquacultural activities are conducted directly in the marine or brackish environment, this accumulation may well lead to a process of eutrophication, with associated depletion of oxygen near the sea-bottom or throughout the water column and a proliferation of unicellular algae, some of which may be toxic. Compounding these problems is the pollution by pesticides and antibiotics, used intensively when animals are raised in such high densities. The result is a serious loss of local biodiversity. This has particularly occurred in sheltered waters, such as with salmon in Norwegian and Chilean fjords, with the raising of oysters and mussels in lagoons and estuaries, and with the raising of shrimp in ponds.
When aquaculture employs the construction of special installations, such as ponds, the impacts are even more pervasive. The most extended example of intensive aquaculture, and that which has been promoted most aggressively by international development banks and institutions, provides a good example, shrimp aquaculture. Farming shrimp and prawn, or "pink gold", for the lucrative markets in the North, is the most prominent example of the social and environmental consequences of intensive aquaculture practised on a big scale. It has grown quickly in South-east Asia, Ecuador and Central America. In 1990 Asia alone accounted for 80% of the world total, covering 820,000 hectares which produced 556,000 tonnes. Principle markets remain Japan, the United States and Europe with a total market value of nearly US$7 billion.
Shrimp culture is one of the main causes of the destruction of mangroves. In Thailand 40% have been destroyed and the clearing for pond construction is only one part of the story. Although there are hatcheries for shrimp larvae, when this supply is not sufficient, larvae are fished from wild mangrove systems using very fine-mesh nets that also sieve out big quantities of other marine organisms.
Shrimp aquaculture is not only conducted in mangroves, but also on agricultural lands close to water bodies. Besides the displacement of farmers and rice culture, the high needs of fresh and salt water lead to a drying of underground waters sources, with a subsequent penetration of saline water. Such deterioration means that the average life of aquaculture farms is only 3-5 years before being abandoned, leaving behind salted, polluted land of no further agricultural use.
Behind these environmental costs, there is the social price that local communities pay by losing access to both aquatic and mangrove resources. In Bangladesh, for example, shrimp farmers have priority in leasing land, which has deprived local people of their rights for common land and public water bodies. Government regulations to encourage export often worsen the problem. In the Philippines, fishing unions have protested that bays where they fish have been obstructed by fish pens. Despite this it is still local fishers who provide most of the fish that is locally consumed.
The instability inherent to such intensive farming systems results in local communities being unable to participate. In the words of Roger S.V. Pullin, the Director of the Inland Aquatic Resource Systems Program of ICLARM: "For stand-alone fish farms, a farmer might expect a total loss or at least serious loss of profits at least once in 10 years and perhaps, on average, twice in 10 years. This would mean bankruptcy for some commercial operators, and life-threatening situations for some resource-poor farmers in developing regions". Later, the inevitable environmental degradation resulting from intensive aquaculture forces operators to change their locations. Both factors have made the sector the domain of capital-intensive operators who do not need to bear the costs of environmental degradation, that is investors who are able to put their returns into other sectors or companies able to find new sites for their operations.
Dazzling export figures hide enormous costs for the countries that export shrimp. The annual profits from these operations in the State of Andhra Pradesh, India, are estimated at 15,000 million rupees. However the Third World Network estimates the negative impacts on local communities and the environment at 63,000 million rupees, far outweighing any production gains when viewed in the wider perspective. Indeed a coalition of Indian NGOs has won a legal challenge on the right of the shrimp industry to destroy the rights to livelihood of millions of coastal people. Their actions led the Supreme Court of India to dismantle existing installations and to ban new operations.
Impact on biodiversity
Aquaculture has relied on fish stocks from a narrow centre of origin with subsequent inbreeding causing impaired genetic performance. A classic example is that of the cultivation of tilapia in South East Asia. As Pullin explains, "Some fish were collected from open waters in Egypt in 1962 and shipped to Japan. Some of their descendants were shipped to Thailand in 1965 and they produced a strain that has been widely farmed since then. A few fish of this strain were shipped to the Philippines in 1972 and their descendants have since been farmed there".
In spite of the selection efforts by Filipino farmers, in 1989 their tilapia turned out to be less efficient than new founder stocks collected from the wild in Egypt. As a solution to this problem, the ICLARM launched a programme in the middle eighties to develop genetic resources for tilapia, that has lead to the creation of the "super-tilapia", using Egypt's wild populations.
To understand the impact of such escapes and releases it is necessary to take into account that, particularly in freshwater hydrological systems, populations have adapted to their environment through particular genetic combinations. If large enough numbers of introduced fish interbreed with wild populations of the same or related species, these particular combinations of environmental adaptation are lost. Small wild populations are particularly susceptible to this kind of genetic contamination.
A good illustration of the scale of escape in aquacultural systems is salmon. Adult salmon are raised in giant cages floating in the sea, close to the coast. In 1995 the number of salmon known to have escaped from Norwegian salmon farms increased to almost 650.000 from 570.000 in 1994, and the same year the proportion of fish of farmed origin in samples from the coastal fisheries was 42%. In the Magagudavic River, Canada, 1995 estimates were as high as 90% of salmon caught being of farmed origin.
Even if there is no interbreeding or released fish are sterile, there are other potential effects on wild populations which are often impossible to predict. It is well known that many native populations of Atlantic salmon in Norway are threatened with extinction, from a parasite introduced through genetically resistant salmon populations from the Baltic Sea. The most severe case of extinction caused by an introduced species may be the case of the Nile perch, which lead to the loss of nearly 200 unique species of cichilds in Lake Victoria.
Perhaps the most pervasive effect of the Blue Revolution is that the rise in production of carnivorous fish (accounting for all the luxury fish raised) and shrimp has translated into a larger demand for fishmeal, which has to be obtained from wild fisheries. World-wide, a third of fish catches are devoted to fishmeal. The rise of particularly shrimp production, has introduced new fisheries to tropical countries where they were virtually unknown previously. In Thailand, this has already been translated into "biomass fishing", whereas before the sea bottom was trawled for shrimp, with the rest of the species discarded or sold in local markets, now it is done to extract anything that can be turned into fishmeal. However many of these species have been part of the traditional food of coastal communities. As a result of these destructive practices, people are deprived of cheap protein. In Indonesia, demand for prawn feed is making unaffordable previously inexpensive and locally available products such as sardines. In Malaysia, the same phenomenon has resulted in a shortage of fish for the salted fish industry.
With local communities marginalised, unable to participate in the system, and bearing the environmental consequences, intensive aquaculture is of no benefit. There is little evidence either, to suggest trickle down benefits from export earnings. From the national perspective, the blue revolution results in a transfer of cheap protein form the South into less abundant expensive protein to be exported to the North. The economic and monetary crisis in South-East Asia shows that relying on currency and external markets, rather than ensuring internal production for food security, may be a dangerous gamble.
Enter Genetic Engineering
In January 1996, for the first time in history, genetically engineered salmon was grown in a commercial hatchery in Loach Fyne, Scotland. The AquAvantage Bred Salmon were genetically engineered for accelerated growth rate with a technology developed by a research team from Memorial University, New Foundland, Canada. The technology transfer was mediated by the Boston based A/F Protein.
The application of genetic engineering to fish started in 1982 with the familiar moral justification of the need to feed a future world population, as NASCO puts it, "The predicted demand for aquatic organisms from a rapidly increasing world population will require increasing use of biotechnology in aquaculture". Developing countries are encouraged to get on the wheel as soon as possible, "The ability to produce transgenic fish and shellfish in culture, which grow faster and to a larger size with more efficient utilisation of nutrients, is of particular value to developing countries, not only as a source of food, but also as export products", states a World Bank Discussion Paper on Marine Biotechnology and Developing countries. It comes down to a question of faith in technology, but before engaging in it, countries should ask themselves whether genetic engineering in aquaculture provides a solution to the real problems. Failure to address key questions such as the environmental stress on marine ecosystems with their resulting impoverishment, and the progressive marginalisation of coastal communities from economic and nutritional livelihood, may result in gene technology compounding the existing crisis.
Trial and error
Behind the promises of the technology, fish genetic engineering is so far very inefficient and random. The most frequently used methodology consists of inoculating the desired genes egg by egg, or embryo by embryo. The idea is that the gene will be incorporated into the egg's genome and then expressed in the transgenic adult. Injecting fish eggs one by one is tedious and requires skilled operators. The efficiency is low with the average number of transgenic fish obtained from inoculated eggs usually ranging between zero and 13 % of those that survive.
The largest part of current research efforts is devoted to developing techniques that allow large-scale transfer of genes into fish. Teams around the world are busy trying to develop more efficient "mass transformation" methods such as electroporation, particle bombardment, the use of liposomes and sperm cell vectors, so far with little success. The reality of fish genetic engineering today is more a question of luck and tricks than a comprehensive understanding of the processes involved. Added to this, even the NASCO acknowledges that many genetically modified fish are highly inbred.
Although there is much basic research to be resolved, scientific teams have embraced applied research, and have not disregarded patents in the process. Increasing the economic appeal of aquaculture has provided the motivation to focus on three lines of research into faster-growing, freeze-resistant and disease-resistant fish.
Feed accounts for roughly half the operating costs in fish farming. Growth rate and food conversion efficiency of cultured fish species is of utmost interest to aquaculturists. The first fast-growing transgenic fish, a common carp incorporating a mouse promoter gene linked to a human growth hormone gene, was developed in China in 1986. Scientific teams from the US have since genetically engineered carp and catfish, while British and Cuban groups have centred their efforts on tilapia and Canadian scientists have focused on salmon and trout. Over time, and in order to avoid the sensitivities of consumers, scientist have increasingly used gene constructs containing only fish genes.
It is Canadian scientists who have achieved the most dramatic results with transgenic salmon growing up to 10 times faster than control groups. This was done by adding the growth hormone gene of a chinook salmon, controlled by an ocean flounder antifreeze gene promoter. It is these fish that have been exported to Scotland. A further gene construct based on the Pacific sockeye salmon created transgenic salmon that were on average more than 11 times heavier than non-transgenic controls, with one individual an extraordinary 37 times larger. However, such top growers paid their price by showing cranial deformities and opercular overgrowth. At one year old, the deformities became more severe and were followed by death.
The Canadian research team is also researching the production of freeze-tolerant fish. The cultivation of salmon, for example, is limited to certain latitudes because if water drops below zero degrees celsius the salmon's cells freeze and the animals die. However, some demersal fish species thrive in waters under ice, such as the ocean pout, thanks to a protein that prevents their blood freezing. Canadian scientists had the idea to isolate the anti-freeze protein gene from a winter flounder and insert it into the salmon's genome. Results proved disappointing with the salmon producing only one percent of the protein level naturally found in the flounder. It was while doing this experimentation that by chance scientists discovered that the anti-freeze protein gene promoter, activated growth hormone expression.
With fish under high density cultivation being particularly prone to sickness, the interest in disease resistance is understandable. For viral infections, there have been several approaches to disease resistance. One of them has been the use of antisense technology which a Japanese team has used to genetically engineer trout resistance to the necrosis blood virus. Several approaches have also been undertaken to fight other infections. Canadian teams working on salmon are targeting a trout gene as a bacterial inhibitor. Another approach, undertaken by a team working in New Zealand, is to insert the genes encoding for biologically active peptides from frog skin.
Although these represent the main areas of research, other points have caught the scientist's attention. A Japanese team is attempting to develop a gene to make freshwater fish tolerant to salt and vice versa. Another line of research relates to genes involved with skin pigmentation, with the economic motivation to tailor fish colour to culinary and ornamental tastes.
Compared with plants, transgenic fish research is still in its infancy and to a large extent carried out by public research centres or institutes, which have established large teams which cross national borders and have established close working relationships with their counterparts. It is yet to be seen whether these relations will survive in if technologies are introduced on a commercial scale.
Risks from transgenic fish?
Our knowledge of the marine ecosystems remains superficial and ignorance of both short and long term effects of transgenic fish is necessarily poor and schematic. One certainty we have is that transgenic fish will escape into the rivers and oceans in the same way that their non-transgenic relatives do.
In the case of fast-growing fish, their effects on wild populations and ecosystems would depend on weather these fish grow faster because they eat more or because they are more efficient. In the first case, they would present more competition to wild stock. The increased size at a given stage in its life history could result in transgenic fish competing with other species of the ecosystem or in its predators not being able to feed from it.
The case of the freeze-resistant salmon would allow this species to colonise entirely new ecosystems where they could compete with the existing carnivorous species. Such a scenario leaves open the possibility that it could thrive and invade large areas. A situation that would be compounded if the genetic character was transmitted to wild salmon populations. A similar story of species advantage disrupting the natural balance would also be the danger with disease resistance.
Although in the long term the aquaculture industry would be affected by such interactions, the fishing sector would be the first one to note the impact of the release of transgenic fish into the environment. As an answer to prevent these problems, scientists argue that it is possible to design transgenic fish which are unable to reproduce, a claim that is far from proven. Even if such modifications were achieved they could alter the behaviour of the transgenic fish with a resulting impact on wild populations or ecosystems. The point is not whether such risks are acceptable, but if they are needed at all. Proponents of the Blue Revolution technology, who continuously remind us of the need to feed the world, will affirm that we need to bear the risk, but where is all this leading to?
If the trends of over-fishing, intensive aquaculture and genetic engineering are taken to their extreme, the image that comes to mind is that of impoverished marine ecosystems producing large amounts of "designer" fish, under the control of corporations able to invest in and maintain such systems. In this brave new world, cultivating the aquatic environment would be a task of industry and the role of the people would be reduced to indispensable workers and quiet consumers of more or less sophisticated fish protein. This industrialisation of the aquatic environment is in fact, the very core of the Blue Revolution.
It is certainly true that the world will have to feed a growing population, but it is even more urgent that it starts feeding its current population and does it in a way that does not pre-empt capacity to continue in future. Instead of trying to resolve existing problems by developing new answers that will invariably lead to more problems, a better solution would be to solve existing problems and look into the available alternatives that can nurture the base of life: diversity.
The initial step towards this objective is to review fisheries management. After taking into account both the degree of exploitation of our seas and oceans and its direct and indirect impacts, it seems clear that, under current fisheries practices, the present total catch is unsustainable. Two questions then come to mind. Would it be possible to maintain current harvest levels in a sustainable way? Also, would it be possible then to even increase it?
The answer to these questions depends on who you ask. The FAO maintains that marine captures may be sustainably increased to 20 million tonnes if a number of conditions are met. Namely that degraded resources are rehabilitated, under-developed resources are exploited avoiding over-fishing, and discards are reduced. Other voices propose a radical change in the very heart of fisheries management, including its underlying assumptions. According to this approach, the main objective of fisheries management should be the protection of marine resources against the causes that lead to their over-exploitation. In the long term, such a change would not necessarily mean a decrease of the harvest. In the waters of the European Union, it would be possible to obtain a level of catches similar or even larger than the ever-dwindling amounts that the EU member states over-fish year after year, if proposed management practices were adopted. An approach that is concerned with maintenance over merely conservation could be defined as a harnessing approach, such as has been the root of the way many coastal communities have managed their fishing grounds for millennia.
Having been plundered for all they are worth, the world's oceans have become impoverished, drained of the rich biodiversity that once fed so many. For an industry desperately seeking to secure supply for continuing demand, the short term fix of the Blue Revolution is an attractive one, if not the only solution to industry's own survival. Supplying prawns to restaurant tables in Rome, Washington or Tokyo may bring in ready cash, but it is devastating for aquatic ecosystems and the millions of people who depend on them for their livelihood. Both intensive aquaculture and genetically engineered fish are the last-gasp efforts of a dying industry trying to sustain itself and should be clearly seen as short-sighted in approach. The sorriest players in all this are the international banks and institutions, who instead of supporting the sustainable fishing practices of the South, are instead lending millions to industry to keep the North in luxury fish. Existing integrated aquacultural systems provide a prosperous alternative to the Blue Revolution which could be successfully enhanced in the future.
This article is part of ongoing work by Anna-Rosa Martinez. A fully sourced version is available from her at GRAIN.