Indian piscicidal plants

Abstract

Fish catching with the aid of plants is an ancient practice. Plants have been used in various parts of the world by primitive people from times immemorial for poisoning or stupefying fish. The practice is one of great biological and ethnological interest and has attracted the attention of both travelers and scientists. In recent times, however, this method of catching fish has been condemned and in some countries even declared illegal. All parts of the plant have been used; but in most cases a certain part only, such as the bark or root in which the toxic principle is located, is utilized. The usual method is to mash the plant or a plant part between stones, and throw it into a pool or netted-off section of a stream. Some workers have suggested from their studies of reactions of fish to the poisons that they affect the respiratory organs (27, 28). Rotenone and allied substances have been reported to exert their action in or via the gills. It appears that such substances enter the blood stream of fish via the gills and then spread to vital organs, the central nervous system, where they are reported to inhibit the respiratory reactions in mitochondria (27). The saponins, on the other hand, have been reported to act chiefly by lowering the surface tensions between water and the gills, thus preventing the uptake of oxygen by the fish and leading to slow death by oxygen deprivation. Fish and other "cold-blooded" animals are said to be particularly sensitive to the toxic effects of saponins (19). At present there seems to be no evidence to prove that the fish obtained by the use of poisonous plants are in any way rendered unwholesome as an article of food, although a tendency to putrefy sooner has been reported.