Английский язык: Сборник текстов и упражнений для студентов специальностей "Промышленное рыболовство". Дьякова Н.П. - 49 стр.

grass carp on rooted aquatic vegetation. Thus various food supplies are used by vari-
ous 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 cul-
ture system). Depending on expected production, the ponds may be fertilized, or pre-
pared feeds may be offered. In Europe and Israel, common carp 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. Hor-
mones may be injected into the adults to induce spawning. Eggs and milt may be ob-
tained by manual stripping. The eggs are maintained in a hatchery and the young fish
are stocked into nursery ponds. The system is relatively simple. Carp are able to tole-
rate fairly wide ranges in environmental conditions, so the technology required for
their culture is not highly sophisticated. The second most widely cultured group of
fishes in the world today are the tilapias. Tilapias are native to the Middle East and
north Africa, but have been introduced throughout the tropical world and into many
subtropical areas. Most species die when water temperatures fall below 100C. There-
fore, culture in temperature climates depends on production of a crop during the
warm months and maintenance of brookstock in warm water (often in indoor heated
holding facilities) during winter. Various species of tilapia are under culture around
the world today, primarily in the tropics. All off the popular ones are known for their
rapid growth, ease of production and heartiness. Tilapias are extremely tolerant of
poor water quality, reproduce readily in almost any environment and reach market
size within several months. Most species feed on a combination of plants and ani-
mals, and they do not require high cost prepared feeds unless they are being reared at
high densities where natural food supplies become exhausted. Tilapias are popular in
subsistence culture in much of Africa, the Far East and Liatin America. Commercial
production is highly developed in Israel, Indonesia, the Philippines, Thailand, Tai-
wan, Jamaica and various other nations.

                                     Vocabulary

      common carp                              культивируемый карп
      big head carp                            большеголовый карп
      silver carp                              толстолобик
      grass carp                               белый амур
      to fertilize                             удобрять
      waste                                    отходы
      to feed on                               питаться
      benthos                                  бентос
      vegetation                               растительность
      pellet                                   гранула
      density                                  плотность

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