Many regions of Europe have a continental aquatic medium, very appropriated for the culture of autochthones cyprinid fishes, as tench. This fish is appreciated in Europe as a refined dish in the restaurant, a piece of angling and also as ornamental fish. In the food market, it has an important potential as a consumer-friendly product, due to its excellent flavour, good appearance and little fish bones. Tench has been cultivated extensively (by natural reproduction system) in the ponds of Central and Eastern Europe for more than 500 years. The natural reproduction cycle of tench makes this fish not available in the market all along the year, because of its limited spawning period, between May and August. Moreover, its semi-intensive production cannot avoid that large number of them die in the first year, growing is very slow at first, and they spawn for the first time not before their forth year.,The development of an intensive tench culture (inducing the reproduction during the whole year, and optimising both survival and growth of juveniles) is largely dependent on reproduction issues (seasonality of spawning, asynchronous spawning), feeding affairs, and environmental factors (illumination, temperature, welfare). In order to create an optimum procedure for intensive production of tench, RTD partners will study the method to assure a good rate of continuous fry production (reproduction and nursery aspects), the food composition more adequate according tench requirements, a protocol to guarantee the survival and adequate growth rate of juveniles, and the study of the better conditions to commercialise them.,The culture of tench presents some advantages, due to its low necessities: it is a fish able to live with low level of oxygenation, and to bear high densities. ,The implantation of an intensive culture of tench responds to the need of promoting and diversifying the freshwater aquaculture, increasing the sustainable production of a wide range of species. Moreover, this will contribute to the creation of stable employment in rural depressed regions.,PROTENCH project has a main objective: the application of the scientific achievements in an intensive system of culture that allows the sustainable and continuous production of fry and adult tenchs. Up to now, studies on different aspects of tench biology have been developed, but never with the integrative approach that PROTENCH try to include. If this objective is focused taking into account all the aspects involved in the commercialisation of this fish, the result will be a new and successful sub-sector in aquaculture. This will permit fish farms to aim its production at a niche of market corresponding to a high value new freshwater fish, with steady and low costs production.,In order to achieve this general objective, different challenges must be faced (which can be considered as sub-objectives):,Steady production of tench fry. The complex regulation of reproduction in fishes is a main problem in aquaculture that usually puts up the price of facilities. In tench, a major problem is that they only spawn (that is, they produce eggs) between May and August, mostly July, when water temperature is at least 18ºC, and they spawn for the first time when are at least four years old. PROTENCH results will mean the knowledge of optimal environmental conditions, hormonal treatment and timing for a successful artificial spawning at any time along the year.,Juvenile survival. Artificial reproduction of tench has not been achieved so far with a sufficient rate of viable juveniles. Large numbers of them die in the first year, probably during the winter. Moreover, the long fry period of these fishes and slow growth make the production period dangerously long, so as attention must be paid on meticulous control of water quality all over the growth process. Another aspect to take into account is the lack of a food that responds to the specific necessities of this species. Both survival and growth of tench have been improved with a supplement of Daphnia in the diet, compared with current trout fodder (Quirós and Rodríguez Alvariño, 1999). But this practice means an extra cost that can be avoided with an adequate food. In PROTENCH it will be determined the fundamental nutritional requirements of tench.,Production line concept. Nowadays, the need of a fixed tench production, which can be estimated with precision and permit a sustainable profitability for farmers, is not met. PROTENCH aim at achieving a protocol for all stages of the fish culture, from brood-stock to market-sized fish, which means the economic security required by farmers. This project tries to set up a clear and efficient methodology that assures the estimated production, and thus profitability in the farms. ,Distribution. According to the previously said, PROTENCH will face up to the distribution aspects that must be taken into account in the "production line concept, and as part of their total production cost. Particularly, the transport of live tench will be accomplished, in order to deal with the expected increasing use of this species as restocking fish. Equally, the distribution and promotion of consumption of this fish will be a major.
Aquaculture; Co-operative research project
Czechia, Greece, Spain, Norway, Romania, United Kingdom