When evaluating the level of pond fish culture in Czechoslovakia, we often encounter the view that this culture is mostly of an extensive nature. This is based on the simple comparison of our production per hectare with those of other countries (the average Czechoslovak fish production per ha is 290 kg). In our opinion this conclusion is not objective.
The results of pond management are subject to the immediate effect of geographic and, in particular, climatic conditions. For this reason, it is impossible to make direct comparisons with the results obtained, for instance, in Yugoslavia or Israel. Such a comparison neglects the most important production factor - the duration of the growth period. Under the best conditions, we in Czechoslovakia may rely on five productive months annually (May to September).
The analysis of results from other countries indicates that the main method of intensified fish culture is feeding, i.e., direct application of complete, often high-cost industrial feeds. Czechoslovakia cannot use this method because of the unavailability of sufficient supplies of such feeds. Experience with intensified pond fish culture indicates that if feed rations similar to those used in other countries are applied, we can almost immediately increase production per hectare two or three times in half of our ponds.
Among the negative factors affecting our fish culture establishments is the fact that most of the ponds are 300 to 400 years old or even more. They were established under completely different production conditions and many of them no longer meet the present requirements of modern pond management (unsuitable depth, bottom size, location in landscape). This is no doubt a considerable drawback in comparison with pond management in Yugoslavia, Hungary and other countries where ponds are of recent construction, thus allowing for the introduction of up-to-date methods based on modern principles. In addition to this, the considerable age of the ponds causes large differences between the cadastral and actual productive pond area. Fish production in Czechoslovakia is converted to values per cadastral area. The conversion to the actual productive area would result in an immediate increase of average crops to 320 kg per ha within the State Fisheries Trust as a whole. On the other hand, this unproductive pond area is a reserve for the development of fish culture in Czechoslovakia and for this reason increased attention is paid to the reclamation of pond banks.
When evaluating the intensity of fish production it is impossible to reduce the management of water areas only to the production of fish; the final production can include also the results of other activities practised in the same water area. In Czechoslovakia it is typical that fish culture is combined with duck breeding (Figs. 14–18) which is now being combined with still another economic activity - breeding of geese. We have achieved an extraordinary rate of development in this branch of additional production. Within a period of 20 years, the average production increase was 3 800 metric centners (380 000 kg) of slaughter ducks, and the technical and labour resources of the State Fisheries make it possible to achieve further enhancement of this trend. From the modest beginning in 1950 and 1951 the State Fisheries Enterprise has become the largest producer of slaughter water fewl in Czechoslovakia.
The development of duck breeding can be illustrated not only by the total production volume, but also by high efficiency, particularly in the reproduction capacity of Peking ducks which are thoroughbred and improved in Czechoslovakia (145 eggs per laying duck), high hatchability (103 ducklings per female duck), growth rate (2.5 kg in weight per 55–56 days of rearing), and fattening (3.3–3.5 kg of feed per 1 kg of gain).
It is necessary to emphasize at the same time that in these water areas we practise a uniform breeding system - the carp-duck system. Although the movement of ducks on the water entails some increase in the maintenance ration, it contributes to smooth and uniform development of their muscles, prevents the formation of excessive fat in the slaughter birds and exerts a favourable influence on their feathers. At the same time the duck excrements constantly manure the water, thus stimulating the development of the natural food for fish. The carp-duck system is not only peculiar to Czechoslovakia; it is a highly developed and elaborate method contributing to a large degree to the prosperity of both kinds of production.
The rearing of more than 75 000 metric centners (7 500 000 kg) of slaughter water fowl brings an additional increase of 180 kg every year to the final crops of fish, so that at present the final production of fish and poultry meat per hectare of ponds is 470 metric centners (47 000 kg) within the Trust as a whole.
Taking into account these relationships and particularly the fact that the present level of production in fish breeding is achieved due to the 60 percent contribution of control of the environment (manuring, improvements) and breeding methods, then it must be recognized that Czechoslovak pond management can bear the comparison of production intensity with that of other European countries. Hence, I can claim, without any exaggeration that the importance of Czechoslovak pond management is not only the result of rich tradition, but also it stems from the present achievements.
