4Bullhead

Bullhead is a popular recreational and food fish in the Great Lakes basin. Experimental work indicates that black bullhead survives and grows well in ponds or cages. They do best in turbid waters.

5Carp

Carp, an important finfish in the world, has minimal but growing demand in the United States. Technology to culture carp in ponds is well known and the fish is suited to conditions throughout the United States. The principal obstacle is poor consumer acceptance. Carp could provide a dependable supply of fish for use in value-added products such as surimi and fish sausage.

2. Grass carp or White amur

White amur is occasionally stocked in ponds to control aquatic vegetation. The sterile triploid is most commonly used. The fish survives well and grows rapidly.

7.13 Render the following verbs with ing-forms into infinitives and translate them:

Model: growing – to grow

Considering, existing, farming, recirculating, flushing, stocking, leading.

7.14 Translate the given Russian words into the English ones:

1. Tilapia are (тропический) fish.

2. Golden shines are cultured in (пруды).

3. Golden shiners require (два) growing seasons to reproduce.

3. Eggs of white suckers are (полосатые).

5. Bullhead are popular (платная рыбалка и пища) fish.

6. Carp is an important (рыбный объект) in the world.

7. White amur survives well and (расти) rapidly.

7.15 Answer the question

1. Why are the following aquatic species less popular in the United States?

UNIT 3

CULTURE SYSTEMS

Active vocabulary

compacted	плотный, массивный, сжатый
slope	уклон
ration	соотношение, пропорция
shallow	плоский
management	управление, умение справиться с чем-либо
to exceed	превышать
drain	дренаж, осушать
inflow	втекающий, впадающий
to be in stock	иметь в наличии
linear	узкий и длинный, подобный линии
raceway	лоток, рыбоходный канал
to expose	подвергать, зд. Оставлять
cage	садок, изолятор
net-pen	садок, огороженное место сетями для выращивания объектов марикультуры
hatchery	инкубаторная станция

8 Culture systems

0. 8.1 Read the following international words and translate them.

1. Culture, system, typical, ration, erosion, yards, acre, static, minimum, industry, production, period, minutes, structures, natural, meters, practiced, limited, farmers, operations, commercially, storms.

3. 8.2 Give Russian equivalents of the following words and word combinations.

Side slopes, steeper slopes, to remove water completely, to maintain higher densities, a leaner channel, a circular tank, to have a drain, freshwater environment, marine environment, to withstand storms.

8.3 Read and translate the text with the help of a dictionary.

Ponds.

The primary culture system used in the world today is the earthen pond. A typical pond is about 3 feet (1 m) deep at the upper end and 6 feet (2 m) deep at the drain. The bottom and sides are made from compacted earth sides slope at a ration of 2:1 or 3:1. Steeper slopes make entry and exit from the pond difficult and promote erosion of the banks, while shallower slopes promote the establishment of aquatic weeds. Pond size varies greatly – some are only a few square yards in area, but most are an acre (0,4 ha) or larger. Management and harvesting become difficult if a pond too large, so most culture ponds do not exceed about 20 acres (8 ha).

A well designed pond should have a drain that allows the water to be completely removed within a day or two and should be provided with an inflow pipe of sufficient size that the pond can be filled within a reasonable period of time. Ponds can be stocked at various densities. If water is exchanged continuously or frequently, higher densities of culture animals can be maintained than when static conditions are employed. Catfish farmers in Mississippi are annually producing over 4,000 ponds per acre in ponds

Raceways.

R

Raceways at a West Virginia fish hatchery

aceways are linear channels or circular tanks through which water continuously flows at a rate that will provide a minimum of several exchanges each day. Raceways are commonly used in hatcheries for the rearing of young animals and are employed by the trout industry for production from fry to harvest size. In ponds fish are exposed continuously to the same water during the grown period, while in raceways the water may be exchanged completely every minutes to every hours.

Cages and Net-Pens.

Culture cages and net-pens are structures placed in a natural environment and stocked with fish for grow out. The only real difference between the two is size. Cages tend to be relatively small (a typical cage has a volume of 1 or 2 m²) while net-pens are often several meters on a side and 10 to20 meters deep. Cage culture has been practiced to a limited extent by catfish farmers. For example, in Arkansas (where leasing of state lakes for cage culture operations is possible), catfish have been commercially produced in cages. Cages have been used by researchers. Most cage culture is conducted in freshwater environment, while net-pens are most commonly used in the marine environment. Net-pen culture has been restricted to protected waters, but recently, net-pen engineering has advanced to the stage that open sea pens are now available that can withstand storms without damage.