La production de tilapias en eau chaude industrielle en Belgique. Situation actuelle du projet, perspectives de développement en pisciculture solaire et transfert de la technologie

For the last years the culture of tilapias has been growing at a high rate in many parts of the world. This paper reports on the main steps of an applied research programme conducted by the University of Liège since 1977, in view of developing a technology of intensive tilapia culture in the heated effluent of the Tihange nuclear power plant on the River Meuse. This research allowed a commercial fish farm (PISCIMEUSE) S.A.) to be created on the site in 1984. Since it started running, the Tihange warm water fish farm has produced 240 tons tilapias which represent 70 % of the all fish species production. The development of an industrial tilapia farming in Belgium was based upon a thorough knowledge of the main biological features of the Nile tilapia (Oreochomis niloticus). Most attention was paid to analyzing how various endogenous factors (sex, size) and exogenous factors (environmental factors such as temperature, feeding level, population density) influence reproduction and fry recruitment, growth rate, food conversion efficiency and bioenergertics. The paper gives some examples of mathematical relationship and models built as tools for optimalizing the tilapia production system. As far as the transfer of the Tihange tilapia culture technology to developing countries is concerned, it appears that many biological data collected during the research would be of prime interest for orienting the good choice of the species to be cultivated in a particular area or for assessing the potential productivity of any system according to the local temperature regime of the water. On the other hand, there is strong evidence that i) a running water tilapia farming is only conceivable if water is available from a dam-reservoir or a very low cost pumping and that ii) feeding with high protein pellets must be replaced by more appropriate and cheaper methods implying a maximum exploitation of the natural biological productivity of the water bodies in use. When evoking the PISCISOL Project - a prototype of a solar semi-closed fish culture unit in the conception and realization of which the University of Liege participated, the paper emphasizes some possibilities of semi-intensive tilapia culture involving an utilization of solar energy for heating water (passive+ active systems) and growing algae and other plants valuable as tilapia food.