Fish Farming Helps To Combat Pollution

Press, Volume CIX, Issue 32067, 15 August 1969, Page 4

Fish Farming Helps To Combat Pollution

Fish farming, * growing source of protein foods. Is helping to provide an answer to the growing menace of water pollution. Polish scientists are experimenting with ways of converting non-toxic industrial wastes, rich in organic compounds, into fertiliser for enriching ponds used in fish culture.

At the laboratory of water biology of the Polish Academy of Sciences in Crakow, sugar industry wastes have been successfully used to fertilise carp ponds. Fish production in test ponds in Golysz increased five times by using such wastes.

Almost similar results were obtained at the Research Institute of Fisheries and Hydrobiology in Vodnany, where effluents from starch factories and waste water from poultry farms were used* Both substances, particularly poultry-waste water, produced life-sustaining plankton in ponds, with encouraging increases in fish production. There was no residual effects. The .experiments are reported in the current issue (Vol; 1, No. 3) of the fish culture bulletin of the Food and Agriculture Organisation, which notes that “fish culture as a means of pollution control is receiving increasing attention.” The bulletin, which contains news on fish culture developments around the world, reports that research is being done in India, at Delhi University, using light to stimulate the breeding cycle of fish. "By exposing catfish to longer day lengths in the non-breeding season by means of artificial light, it was found that the gonads attained maturity three months ahead of the normal season,” it said. The publication also reports a “spectacular increase” in trout production in France and Italy which threatens Denmark’s position as Europe’s major trout exporter. ' Jugoslavia and Poland have begun to export trout to Germany, and the Soviet Union is also becoming a major producer. Mean-

while, experiments are being made to grow rainbow trout in saline water. This would help reduce costs.

In Hamburg, common carp are being bred within the narrow confines of aquariums simply by maintaining a constant flow of water around the fish.—F-A.O. Release.