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 – донные живые организмы (личинки насекомых и др.)
vegetation	растительность
pellet	гранула
density	плотность
ration	рацион
to spawn	нереститься
milt	семенники
strip	выдавливать икру или молоки
nursery pond	садок для молоди рыб
to tolerate	выносить, переносить

Answer the questions

1. What are two the most widely cultured groups of fishes?

2. What have you learnt about Chinese culture system?

3. Why are ponds fertilized?

Part 2

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 in to many subtropical areas. Most species die when water temperature fall below 10ºC. Therefore, culture in a temperate climates depends on production of a crop during the warm months and maintenance of brood stock 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 of 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 fishes feed on a combination of plants and animals, 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 Latin America. Commercial production is highly developed in Israel, Indonesia, the Philippines, Thailand, Taiwan, Jamaica and various other nations.

Vocabulary

tilapia	тиляпия
brood	потомство, выводок, помет
heartiness	крепость, здоровье
food supplies	запасы пищи
hatchery	рыбопитомник
maintenance	содержание, сохранение

Answer the questions

1. What are native areas of tilapias?

2. What makes tilapias very popular around the world today?

3. Where is commercial production of tilapia developed in?

9 Aquaculture species in the united states Part 1

Many aquatic animals and plants are cultured commercially in the United States, while others have been grown for research or demonstration. No one species is appropriate for all situations. Species cultured successfully in one area may prove impractical or unprofitable in another.

Species Cultured

Finfish, shellfish, and aquatic plants are cultured commercially and recreationally for food, bait, stocking, research, bioassay tests, ornamental markets, and as instructional aides. The following species have culture potential for the northeastern United States.

A. Cultured Commercially

1. Rainbow, brown, and brook trout are cold water fish which require well oxygenated water below 65°F. They are cultured commercially in many northeastern states. Pennsylvania and New York are the leading producers in the region. Most trout are grown in flow-through systems; although some culturists currently reuse their water and a few use cages or net pens, Rainbow trout are marketed for stocking and as food fish. Brown and brook trout are stocked for recreational fishing; some are also sold as food fish.

2. Atlantic salmon is native to the eastern United States and better suited to aquiculture conditions than their Pacific coast relatives. The Atlantic salmon has become an important aquaculture species. Atlantic salmon are released as smelts in streams to enhance natural populations and cultured in cages or net pens placed in areas with substantial flushing. Smelts may be produced in freshwater hatcheries or purchased.

3. Fathead minnows are the most important live bait produced in the region. They are usually raised in ponds. Culture ponds are typically fertilized with a vegetable material such as soybean meal or wheat sorts which stimulates the growth of algae. The reresultant plankton bloom is eaten by the fish. Some growers use a low protein, commercial fish feed. Potential markets exist for fathead minnows as bioassay and research animals.

4. Channel catfish are the most important fish currently cultured in the United States. Both fingerlings and feeds are commercially available. Most channel catfish are raised in the southern United States in ponds one-half to ten acres in size. Cage and net pen culture are also practiced. In an existing pond, cage culture represents one way for those considering fish farming to try their hand at fish culture with a minimal cash investment. Catfish can survive a wide range of temperatures and will tolerate brackish water.

5. Striped bass and its hybrids have recently been cultured commercially. They are raised as striped bass or, more commonly, hybridized with other fish such as the white bass, white perch, or yellow bass. Hybrids usually have a deeper body, shorter tail, and more sloped head than the striped bass. Striped bass and its hybrids tolerate a wide range of temperatures and salinities, from fresh to salt water. They are a warm water species and grow best at 75-83° F. The length of the growing season is one factor that determines where they can be raised profitably. Striped bass and its hybrids are cultured commercially in ponds, flow-through systems, and cages.

6. Goldfish and ornamentals are commonly cultured in small ponds or tanks. Because of their high value, recirculating systems have commercial potential. Outdoor culture units maybe covered in winter to protect fish from the cold.