Considering the rapid growth of the demand in aquaculture products, the need to diversify the production and the pressure to reduce the impact of aquaculture on the environment, optimisation of new species intensive culture, combined with the improvement of technologies applied to recirculating systems has been identified as an necessity for the further development of European freshwater aquaculture. The general industrial and economical objective of the present project is the development of a transnational production chain of high value freshwater fish (perch, roach/rudd) mainly oriented towards the food market. The proximate objective is to demonstrate the feasibility and profitability of these productions in an industrial type recirculating system in order to develop an aquaculture engineering activity. Short term objectives are the transfer of technologies towards fish farms using the recirculating system, and the export of newly developed know how. Presently, the grow out farms of perch and roach/rudd do not dispose of a continuous supply in high quality weaned juveniles, due to inadequate techniques of weaning and absence of control of the reproductive cycle and the health environment. Moreover, the growth performances of these species in recirculating systems are relatively poor, due to a lack of knowledge in their nutritional requirements and inadequate techniques of recirculation. Research must be conducted to optimise the performances of the rearing system and the culture techniques.
The first research axis consists to develop in situ weaning practices adapted to the juvenile monoculture production in small ponds. New microbial technologies will be experimented in recirculating systems in order to control the quality of the physico- chemical and health (sanitation) environment and consequently to reduce the mortalities recorded during the larval and juvenile stages. Applied microbial techniques will be used to enhance the development of probiotic bacterial populations, to induce a rapid seeding of the biofilters and to reduce the variations of toxic nitrogen susbstances (ammonia, nitrites). Concurrently, deep modifications will be carried out in the biological filtration and oxygenation equipments in order to increase the tank production capacities.
The second research axis concerns the control of some biological traits in perch and/or roach/rudd. In both species, artificial photothermal cycles, combined with hormonal injections, will be experimented in order to induce off season spawnings and larval productions. The determination of some nutritional requirements (lipids, protein/energy ratio) will be investigated in order to formulate suitable artificial feeds for juvenile and adult fish (perch as carnivorous cool water fish and roach/rudd as herbivorous omnivorous fish). In perch, the techniques of genetic improvement will be used to produce monosex female populations.