Introduction

Various extensive and semi-intensive aquaculture systems have been taking place from the sea to coastal wetlands during the last centuries. Some of them are still effective economic activities in many coastal areas of Southern Europe, with a significant socio-economic impact. Due to environmental risks of eutrophication of intensive production aquaculture systems in coastal areas, in particular in costal lagoons, and increasing demand of consumers on food safety and on cultivated species welfare, extensive and semi-intensive culture products are coming back in the front scene.

Nevertheless, today's production costs in extensive and semi-intensive aquaculture systems are often too high to be a sustainable economic activity in the actual context (high labour costs, high land costs), due to the low productivity of these systems. In addition, such systems are also occasionally pointed, often without scientific evidence, as having negative environmental impacts. Products coming from extensive and semi-intensive culture are also poorly differentiated by the majority of consumers from intensive farming products. In addition, sustainable ways of exploiting the natural resources of the water bodies, and through developing extensive farming an economic activity can be associated with conservation/development of wetlands.

Unfortunately, their dependence on natural processes also limits their productivity, implying a low compatibility with intense economic activity. In addition, the economic viability and socio-economic importance of such extensive and semi-intensive aquaculture system if often limited by technical limitations, as little R&D effort has been done so far in improving such systems, which often rely largely on traditional practices.

Optimisation of existing protocols, and developing of new farming protocols, to enhance productivity of ponds and lagoons, or using certification processes allowing an add-value to products from extensive and semi-intensive systems, could render these activities more economically effective and attractive for new generations of farmers.

Optimisation of production systems

One way to provide ‘added-value’ to the extensive and semi-intensive sector aquaculture in Southern Europe, is by optimising the production systems, while maintaining sound environmental conditions in coastal zones. Several approaches can be used in this endeavour, including:

a) Improved diet formulations can increase production and reduce environmental impacts in semi-intensive farming in ponds/lagoons. The proportion of the nutrients utilized by the fish for growth can maximized, thereby reducing the amount of waste and nutrient output from the fish farms. Undigested, un-utilized and uneaten feeds are the sources of aquaculture wastes. Therefore, selection of very digestible ingredients for feed formulation and avoiding excess nutrients intake are two important factors to reduce farm waste and nutrient output and hence decrease environmental impacts in semi-intensive farming in ponds/lagoons. Moreover, the substitution of fish meal and oil as much as possible by vegetable ingredients will reduce the pressure on natural resources, namely the fishery directed to fish meal and fish oil production. There is also a strong consumer pressure in Europe so that these replacement vegetable ingredients are not produced from genetically modified organisms (GMO-free);

b) New research tools provided by molecular biology may also be instrumental in extensive and semi-intensive farming in coastal areas. The extraordinary progresses made by genetic and molecular biology technologies have been recently extended to important marine aquaculture species. Fish reared in semi-intensive and extensive conditions, like Valliculture, requires peculiar adaptation as important physical parameters largely fluctuate over the year. As a matter of fact Sparus aurata production can be severely affected by the “winter syndrome” associated with temperature decrease, with significant economic losses. Several studies conducted on gilthead seabream have demonstrated immunosuppression and metabolic distress in fishes affected by cold syndrome. However, molecular and genetic basis understanding has never been addressed so far. The functional genomics approach may contribute to identify gene/s or gene networks that play a role in the adaptation process, and may be instrumental in selecting best performing fish strain under aquaculture conditions;

c) A synthesis of pond management techniques (macroalgae control, predator control, natural productivity enhancement, harvest) or other type of management used in different countries and systems may also be very helpful in enhancing production. Literature is abundant in freshwater pond culture, but limited, dispersed (or not published) in marine and brackish pond culture.

d) Optimizing slaughter procedures of fish can also bring ’Added-value’ to the extensive and semi-intensive aquaculture sector in Southern Europe, by improving the quality of marketed products. Slaughter procedures can influence muscle quality from the consumer’s perspective and also shelf life, an important factor closely related to the marketing time during the high quality initial phase of degradation. Evaluation of rigor mortis in fish and sensorial characteristics in these and other species can be used to determine the most effective slaughtering method, which can then be standardized, making easier to compare different samples from different production facilities.

Non-market benefits of aquaculture

However besides technical and economical issues, other dimensions of viability should be considered. The simple recognition of non-market benefits associated to extensive aquaculture such as the maintenance of wetland functionalities, landscape structure or sentinel of coastal ecosystem integrity does not ensure improved economic viability of these productions. The road of subsidizing production for non-market services to the environment has been proven to be a difficult path to improve sustainability. The search for internal incentives such as product value-adding or income diversification may be more efficient. There are many options for that. One is in the differentiation of products based on collective action to build niche markets offering premiums to products from extensive and semi-intensive aquaculture. The other is to consider the diversity of complementary activities than can be developed to generate income in the form of added-value to the product or in the form of other activities benefiting of the environment and image of extensive and semi-intensive aquaculture.

In the area of income diversification, the first option is in adding value to the product by simple processing (presentation, packaging, simple preparation) or more elaborated processing (filleting, salting, smoking, canning...). The other road is to develop activities in relation to tourism and education. Eco-tourism including lodging at the farm, education to the environment and traditional production become a key element to sustain local economies that wish to conserve rich but fragile ecosystems. But there are numerous other ways to derive income from promoting local ecosystems and traditional activities. In many cases both individual initiative and collective action play a major role to develop such dynamic. The research conducted under the thematic network FEMMES (Q5TN-2002-01560) that worked with associations of women in fisheries and aquaculture has demonstrated that women have a central place in building up sustainability by the mean of income diversification (www.fishwomen.org).

Quality of products and certification

In order to make the extensive and semi-intensive aquaculture activities in Southern Europe competitive with intensive aquaculture, some objective criteria are necessary to analyse the impact of this kind of aquaculture on the final product quality. Many works have shown that the flesh quality is influenced by the environment, the production density, the slaughtering technique but also by the nature of feed received during the growing phases. Generally in aquaculture, the feed determine in a rather large extend the flesh characteristics. The analyses of fatty acid and amino acid profile, related to environmental conditions of feeding will be used as indicators to differentiate these products from intensive aquaculture products and will allow evaluating the corresponding nutritional quality of the flesh. Sensory evaluation performed by a trained panel points out the specific characteristics of odour, appearance, texture and flavour of these products compared to intensive aquaculture products.

Moreover, heavy metal and dioxin analyses could guarantee safe product to the consumer and contribute to a better perception of these products. As with other traditional food products (wines, cheese and meet products, for example), farmed fish from semi-intensive and extensive farming methods have potential for very special market opportunities. To achieve the consumer perception in an easier way and with more efficacy European countries developed several certification systems to make more visible the advantages of such products. The adoption of certification processes is certainly desirable and advisable. However, first is advisable to identify quality markers, and develop “codes of conduct ”.