7 Feeding the world through agriculture

Commercial aquaculturists throughout the world are in business to make a profit. When that profit associated with providing food for other people, the commercial aquaculturist is not generally interested in feeding the hungry, but in providing the best quality product possible and selling it for the highest possible price. In some places subsistence culture which involves the rearing of a modest amount of aquacultured product for consumption by a family, group of families, or a village involved in the enterprise is being practiced.

One or a few small ponds can often produce enough fish, for example, to meet the local animal protein demand perhaps even with enough left over to sell profitably. Subsistence aquaculture depends on availability of water in suitable quantity and quality. Water of that nature is often not available, so the aquaculture option may not exist.

Commercial aquaculture is not, in general, a means of providing inexpensive animal protein to the masses. Aquaculture can create jobs, enhance the overall economy of a region and thereby help to improve the plight of underprivileged peoples. It is not a panacea, however, and should not be looked upon as the means to prosperity for large numbers of those who live in the developing nations of the world.

Vocabulary

subsistence aquaculture	аквакультура для пропитания
to enhance	повышать

Answer the questions

1. What is the purpose of commercial aquaculturists?

2. What does the subsistence aquaculture depend on?

3. Can aquaculture feed the hungry of people all over the world?

8 The big two in fish culture Part 1

The most widely cultured groups of fishes in the world are the carps. While the people of the USA are most familiar with the common or European species, carp culture is dominated by production of a variety of Chinese carps including the common big head, silver and grass carps. In the USA the common carp was introduced from Europe during the 19^th century.

The Chinese have developed carp culture to a fine art. They use a system known as polyculture (two or more non-competing species are reared in the same water system) in which at least four species of carp are grown in the same pond. Ponds in China are often fertilized with organic fertilizers which produce plant and animal food for fish. Agricultural wastes may be also used. Common carp feed on benthos, silver carp on phytoplankton, big carp on zooplankton and grass carp on rooted aquatic vegetation. Thus various supplies are used by various culture species. Stocking rates are related to the food supplies. In recent years, prepared feeds have become more common in China, though pelleted diets may still be used in combination with fertilization.

Indian carps (various species) and common carp are more commonly reared in monoculture (only one species present in the culture system). Depending on expected production the ponds may be fertilized or prepared feeds may be offered. In Europe and Israel common carps are maintained at high densities and are fed pelleted rations that meet their nutritional requirements.

Carps will spawn naturally in ponds, though hatcheries are often maintained. Hormones may be injected into the adults to induce spawning. Eggs and mill may be obtained by manual stripping. The eggs are maintained in a hatchery and the young fish are stocked into nursery ponds. The system is relatively simple. Carps are able to tolerate fairly wide ranges of environmental conditions, so the technology required for their culture is not highly sophisticated.