Aquaculture

The seafood of tomorrow

The consumption of fish – a vital source of protein for certain populations, the key to a healthier diet for others – has grown so much that natural resources cannot keep up with global demand. This situation presents a major economic opportunity for aquaculture (or “fish farming”). But numerous environmental and health issues still confront this industry.

Granules being  distributed in sea bass breeding  cages at Cannes Aquaculture at Golfe Juan (France). Ifremer/Olivier Barbaroux Granules being distributed in sea bass breeding cages at Cannes Aquaculture at Golfe Juan (France). Ifremer/Olivier Barbaroux
Salmon breeding at  Vestnes (Norway). A practice that could ‘compensate’  overfishing, and protect local wild species. © WWF-Canon/Jo Benn Salmon breeding at Vestnes (Norway). A practice that could ‘compensate’ overfishing, and protect local wild species. © WWF-Canon/Jo Benn
The Norwegian  aquaculture research station (Fiskeriforskning) at Tromsø is at the centre of the  Ethiqual section of the European Seafoodplus project. Researchers there are  observing the behaviour and stress tolerance of the different breeds of farmed  fish. © Sandie Millot The Norwegian aquaculture research station (Fiskeriforskning) at Tromsø is at the centre of the Ethiqual section of the European Seafoodplus project. Researchers there are observing the behaviour and stress tolerance of the different breeds of farmed fish. © Sandie Millot
Aquaculture in Turkey. This fish farm, close to a holiday  village, is due to be moved so as not to hamper the development of the local  tourist industry. © European Aquaculture  Society Aquaculture in Turkey. This fish farm, close to a holiday village, is due to be moved so as not to hamper the development of the local tourist industry. © European Aquaculture Society

Today, with total production from sea-fishing stagnating at around 95 million tonnes a year, the great hope for the future is aquaculture, which already provides 46% of the fish that reaches our tables. Recent developments in Europe relate essentially to mariculture (saltwater fish farming), which, although representing more than half of the world’s farmed fish production, is relatively underdeveloped in the European Union. “What is complicating this type of farming is the over-exposure of much of Europe’s coastline to the strong Atlantic waves and winds,” Alistair Lane, Executive Director of the European Aquaculture Society (EAS) told research*eu. “But a number of innovations will soon enable us to expand European mariculture. This is a promising prospect, in particular for fishermen already confronted with heavy job losses as the inevitable consequence of overfishing. It makes a good deal of sense to involve them in marine aquaculture, as they know this environment better than anyone,” Alistair Lane concludes.

Aquaculture could therefore constitute an ideal alternative to overfishing, provided that this ancient art is practised in harmony with its environment. The well-being of wild species depends on it, as does the sustainability of the entire sector. With this in mind, in 2002 the Commission launched its first European Aquaculture Strategy, which defines avenues of research for raising production, maintains optimal quality for consumers and guarantees a high level of environmental protection. Despite a wide-reaching consultation in 2007 on this strategy with a view to improving the system, these three fundamental objectives have not lost any of their relevance.

Limiting environmental impacts

There are many environmental issues surrounding aquaculture: excreted nitrates and phosphates, antibiotics and detergents, not to mention the thorny problem of introducing non-native species, to which researchers are devoting considerable attention. The fact is that we still know very little about exactly how marine ecosystems function. And, following the precautionary principle laid down in the new 2002 Common Fisheries Policy (1), given the scientific uncertainty involved, any marine activity should at least be accompanied by a solid pre-evaluation of the environmental risks. Such an approach is also in the interests of aquaculture, as the industry’s profitability is heavily dependent on having a quality environ ment – demonstrated by the regular losses suffered by mussel farmers from the proliferation of certain toxin-emitting algae. But there are other unknowns, in particular in terms of excreta and other waste matter, because seawater fish farms cannot be provided with water recirculation systems and all waste therefore passes into the sea. Specialists are also afraid that escaping farm fish could cross-breed with wild species and affect their genetic heritage, even if our knowledge here is still insufficient. For this reason, quantifying the risks inherent in aquaculture is the main objective of Ecasa (2). This project proposes defining the best indicators to assess the environmental impact of aqua culture in order to develop models that are suited to the different European maricultures.

With marine aquaculture facing fierce competition from other sea users – tourists, pleasure ports, fishermen, etc. – the project also aims to select the best locations for developing fish farms. This project is proving a vital tool in helping fish farmers understand the link between aquaculture and the environment.

Sustainable fish food

European, salt-water fish farming focuses mainly on fish-eating species. The three main species farmed, Atlantic salmon, turbot and sea bass, feed solely on fish in their natural environments. 4 kg of fish are required to produce enough fish meal and oil to obtain 1 kg of Atlantic salmon. This practice poses a serious problem of sustainability, as extending the farming of fish-eating fish will place growing pressure on stocks of the small pelagic(3) fish of low commercial value that are needed to produce fish meal and oil. Vegetal substitutes are already included in fish feed used in farms, but the technology needs to be improved in order to reduce aquaculture's impact on fish stocks. Several research projects are looking for answers to this problem, including Aquamax(4), which is largely financed by the European Commission. This project is aimed at developing new fish feeds and assessing their quality and their effect on the life cycle of farmed fish, on farming methods, on the consumer and on the environment. “The main difficulty lies in defining the ideal vegetal composition to guarantee an alternative, highquality diet. This is a long-term task, as each species has its own specific needs,” says Bente Torstensen, a researcher at the NIFES (5) who is responsible for the Salmon Lipidic Metabolism area at Aquamax. This approach has the benefit of both limiting the use of sea catches and improving the quality of the product. “The natural environment often contains large numbers of pollutants, which are accumulated by natural aquatic organisms,” Bente Torstensen continues. “Minimising the use of captured fish helps us control the contamination level of farmed fish and so limit the risks for the consumer. On the other hand, the use of vegetal resources brings with it the risk of increasing pesticide levels in the product. There is no miracle solution. We have always to carefully weigh up the pros and cons in order to determine the ideal substitute.”

Optimising aquacultural production

A healthy product is most certainly a major concern for consumers, but it is not the sole quality criterion. The fact is that we eat first and foremost with our eyes and are quick to push a malformed fish to the side of our plates. A malformed fish also consumes more food, and therefore represents a loss for fish hatcheries. In the natural environment this phenomenon is automatically regulated by the presence of predators. Defining the factors that encourage the appearance of deformities and modulating them in order to limit losses should help increase hatchery production. Such an improvement would reduce the cost of producing juvenile fish and benefit the entire fish farming sector. Finefish (6), a project managed by the Federation of European Aquaculture Producers (FEAP), is attempting to alleviate this problem by studying the three main factors recognised as influencing juvenile malformation: temperature, feeding and the environment in the breeding tank. “We are trying to determine how these factors can be optimised in order to limit the percentage of malformed fish in five different types of fish farms,” Margreet van Vilsteren, a project assistant at FEAP, tells us. “An initial experimental phase is carried out at the research centres. The results are then tested in situ in the 10 hatcheries taking part in the project. This enables us to test them in a real-life commercial situation, and to guarantee their effectiveness as far as possible.” Other research projects are attempting to use the fact that fish farming makes it possible to control each stage of a fish’s development to increase the beneficial properties of marine produce. In Seafoodplus(7), another wide-ranging research programme supported by European funds and aimed at enhancing the value of marine produce, Edward Schram, a researcher at IMARES(8), is trying to enrich fish fillets with organic selenium, certain composites of which are believed to have anti-carcinogenic properties. He has therefore added garlic, known to be rich in organic selenium, to the meals used to feed farmed fish. The experiment has proved a success: the flesh of the African catfish, which have served as guinea pigs, contains a high concentration of selenium without disturbing their metabolism. “We are now waiting for the University of Madrid to develop an experimental method for identifying and quantifying all the selenium composites detected in the fillets. It’s clear that the selenium has been transferred, but we need to be sure that the targeted substance is indeed present in th flesh,” Edward Schram explains. It remains to be seen how consumers will react. Research in the context of Seafoodplus shows them to be somewhat reticent towards improved natural products.

Julie Van Rossom

  1. See article on fishing
  2. An Ecosystem Approach for Sustainable Aquaculture. The European Commission is contributing € 2.5 million to the financing of this project.
  3. Fish living in the open seas in the upper layers of the water column (0 to 200 m).
  4. Sustainable Aquafeeds to Maximise the Health Benefits of Farmed Fish for Consumers – The Commission is putting up € 10.5 million out of a total budget of € 15 million.
  5. National Institute for Nutrition and Seafood Research (NO)
  6. Improving sustainability of European fish aquaculture by control of malformations – The Commission is contributing € 3 million of the total budget of € 4.8 million.
  7. Health promoting, safe seafood of high eating quality in a consumer-driven fork-to-farm concept
  8. Institute for Marine Resources and Ecosystem Studies (NL)

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A potted history of aquaculture

The first rudimentary fish farms dating back to 2000 BC have been discovered in China and Egypt. A millennium  and a half later, Greeks began cultivating oysters. Valliculture, which consists of holding captive fish travelling up-river to brackish water, first appears in the 15th century. But it was not until the invention of artificial fertilisation of salmon in the 17th century that man was able to master the entire life cycle of a fish species. The 20th century saw aquaculture boom as a new source of protein against a background of an exploding world population. The first eel farms appeared in Japan in the 1950s. A decade later, production of rainbow trout became widespread in Europe and the United States. In the 1970s, amberjacks, catfish and certain shellfish arrived at the first sea pastures,  where the early development stages were controlled in order to repopulate the natural environment. The following decades were to see the advent of new forms of aquaculture, mainly in a marine environment, with the production of salmon, shrimp, sea bass and bream, and very recently tuna, but here the reproduction process is yet to be mastered. In this case, juveniles are taken from the sea and fattened in captivity, a practice that has attracted the wrath of certain environmental NGOs.



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