Jérôme Lazard: "Tailoring aquaculture to territories"

What role could aquaculture play in meeting the challenges posed by the current strong population growth worldwide?
Jérôme Lazard: As a food source for humans, aquaculture has only been on a par with fishing since 2008. Until the early 1970s, production from aquaculture was negligible in relation to the live aquatic resources derived from fishing. However, it has grown by 20% per year over the past 20 years. At the same time, the growth in production from fishing has slowed, and has now reached a plateau. All this has coincided with strong growth in demand due to both population growth and increased protein consumption. The future therefore looks bright for aquaculture.

Is it now possible to determine both the potential and the limitations of aquaculture?
J.L.: In terms of production and potential, it is important to bear in mind that 92% of farmed fish products come from Asia. The centre of gravity of global aquaculture is now somewhere along the border between China and Vietnam. The rest of the world accounts for just 8% of global output, and if we deduct the tonnage corresponding to salmon production, which is a very specific supply chain, there is little left for other continents, particularly Africa and South America, which both have high potential. The latter is clearly beginning to increase its aquacultural output. In sub-Saharan Africa, however, production is apparently low, notably due to a lack of organization and of truly operational sociotechnical networks, and when looking at the sustainability of supply chains, it is important to take account of all four types of governing factors: social, economic, environmental and institutional, ie relating to governance.
According to the results of the EVAD* project to assess the sustainability of aquacultural systems, every system is closely linked to the territory into which it fits. Sustainability diagnoses are as much a comparison of the assets and handicaps of each system as an absolute ranking of the different systems. However, sustainability profiles run counter to portrayals based on an opposition between intensive and extensive systems. The results obtained in Brittany and the Philippines in particularly contradict the prejudice that exists against intensive systems.

What do we know about the impact of aquaculture on maintaining biodiversity?
J.L.: There are generally two distinct situations as regards this major question: the domestication of native species and the introduction of exotic ones. The latter may become permanently established where they are introduced, and even take the place of one or more local species. This type of introduction for aquacultural purposes is generally seen as beneficial, but we do not yet have sufficient experience to judge its impact on native biodiversity. The first case, that of the domestication of native species, concerns the interaction between wild and domesticated species: this is the case, for instance, with Atlantic salmon reared in floating cages, which is genetically different from its "sister" species living nearby in the natural environment. However, captive individuals sometimes escape from farms, fostering the mixing of the two genotypes. Nevertheless, with the exception of systems using recycled water, all fish farms are likely to release domestic fish into the natural environment and thus have an impact on individuals of the same species living in the wild. It is therefore important to avoid being Manichaean in this respect too.

What about the nutritional quality of farmed fish from the consumer's point of view?
J.L.: Fish contains fat, protein, minerals and vitamins. As regards protein, fish composition is identical regardless of whether the protein is of plant or animal origin. Fat composition on the other hand, directly reflects the type of food that fish are given. Over the past ten years, aquaculture has become the main animal product supply chain in terms of fish meal and oil consumption, which has given rise to a certain number of controversies regarding the appropriateness and efficiency of "turning fish into fish" and its role in increasing the pressure on fish resources. To reverse the trend, a major research project is under way with a view to either partly or wholly using proteins of plant origin to feed farmed fish.

What is the fish of the future?
J.L.: There is not just one fish of the future, but rather a range of aquacultural systems tailored to their respective and changing environments or territories. This brings us back to sustainability indicators, which serve to steer the measures to be taken, notably in the form of public policy, to ensure that in a given situation, an aquacultural system will perform as well as possible in terms of sustainability. If we absolutely have to think in terms of fish species, a strictly ecological rationale would favour the use in aquaculture of species with a short food chain that are plant-eating, filter feeders or omnivorous. This is currently the case in Asia, where the main farmed species are carp (Chinese and Indian), tilapia and pangasius, within a range of systems that differ greatly in terms of the degree of intensification. These species - except for tilapia and pangasius that are sold on the export market - are not suitable for markets in the northern hemisphere, where people are more used to eating fished species and thus naturally prefer carnivorous fish - with a long food chain - such as salmon, bass, bream, etc. Again, there is a combination of determining factors that govern whether a given system will be effective. To end on a specifically piscicultural note, it is clear that there is plenty of work to be done as regards diversifying fish farming, since of the 32 000 known fish species, some 200 are currently farmed and just 15% account for 85% of total aquacultural output.

* The EVAD project to assess the sustainability of aquacultural systems has resulted in the development of a method for doing just that, based on a panel of six fish farming systems in industrialized and developing countries. The project was conducted within the framework of the French ANR agriculture and sustainable development programme, over a four-year period (2005-2008), by a group of researchers from CIRAD, INRA, IRD, IFREMER and the University of Montpellier I.

Literature

Piscicultures : le poisson de demain , coord. Jérôme Lazard, René Lésel, Cahiers Agricultures Vol. 18, No. 2/3, March-April/May-June 2009, Publ. John Libbey Eurotext.
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