The pollution of reservoirs
and perspectives of modern fishfarming


óhemical part of report
Volodymyr Man'ko

The cultivation of the fish in natural reservoirs is now complicated by two main factors:

  1. Low quality of water, conditioned by the presence of domestic and industrial pollutants, brought with precipitation and surface collection to almost all types of reservoirs;
  2. Low quality of natural forage, also containing these pollutants, getting through trophic chains to the meat of growing fish during free fattening and in the conditions of stews and nurse-ponds as well.

The only way to obtain ecologically-clean production is to grow the fish in systems with closed cycle of water supply, isolated from natural environment and with controlled quality of water.

Open cycle of water supply operates with relatively cheap water, mostly of low quality. It always requires preliminary preparations, like aeration, purification and heating to necessary temperature. After all preparations the fault of water with metabolic products becomes unprofitable.

The cultivation of sires and hatchering of fry in systems with closed cycle in the regions with cold and moderate climate requires heating and thermoregulation. The resulting rise of expenses stimulates the search of new technologies for qualitative purification of circulating water and methods of an effective hydrochemical monitoring of the content of products of vital activity in the water.

Application of new technical means, which make possible the effective (up to 85%) extraction of fish metabolites from water, is proposed within the bounds of this project

Using of new methods for purification of water from organic and mineral compounds allows to improve the quality if water and to intensify the process of growing of the qualitative meliorating fish, its sires and commodity fish. Proposed process will be realized not as an alternative for biofiltration, but as an addition. New construction makes possible an extraction of organic metabolites as well as soluble salts. Traditional biomethods are not capable to extract mineral components of metabolic products.

Already developed analytical methods can be used for express determination of nitrogen-containing compounds and other metabolites in circulating water without great financial expenses.

Within the bounds of project “Optimisation of Water Use, Ecological Cleaning of Water and Biological Melioration of Various Types of Water Reservoirs” is proposed the series of experiments for the determination of the optimal ratio between the volumes of biofilter and fish-feeding reservoir, and an influence of concentration of metabolic products on the growth and reproduction of fry.

From the chemical point of view an experimental check-up of qualitative and quantitative efficiency and constructive correspondence of new water-purifying system is proposed, as well as the development of optimal cultivation and growing regime and system of technical monitoring of the condition of circulating water.

© Ukrainian magazine "Naturalist"