Vocabulary

pellet	гранула
pellet mill	пресс для гранулирования
extruder	пресс для выдавливания
steam	пар
extruded pellets	экструдированные гранулы
pressure pellets	прессованные гранулы
floating pellets	плавающие гранулы
sinking pellets	тонущие гранулы
shrimp	креветка
to float	держаться на поверхности, плавать
fungus	гриб, плесень

10.11 Put down the corresponding adverb. Translate the words.

Model: typical – typically

Quick, high, usual, short.

10.12 Say if these statements are correct:

1. Ingredients for diet are usually mixed in proper proportions.

2. The diameter of the pellet varies from 5 cm to 6 cm

3. Feeds produced by pressure pelleting are more dense than water, thus they sink.

4. Extruded pellets are the cheapest than others.

5. An aquaculturist cannot see that the fish eat floating feed.

10.13 Choose the proper definition from the right column:

Pellets	pressure, extruded, floating, sinking, flying, swimming
Species	various, aquaculture, fish, plant, chemical, organic
Meal	fish, meat, by-product, corn, pond, organism, fat

10.14 Topic for discussion

1. Speak about the difference between pressure pellets, extruded pellets and floating pellets.

11 GENETICS AND REPRODUCTION

Part 1

0. 11.1 Read the following international words and translate them. (Mind the part of speech).

1. Selective, culture, components, cycle, control, collecting, reproduction, temperature, combination, types, stimulus, hormone, plankton, scenario, typical.

3. 11.2 Give Russian equivalents of the following words and word combinations.

4. Life cycle, brood fish, aquaculture species, hormone activity, pond bottom, culture environment.

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

I

Atlantic salmon smolt next to blood sampling and PIT tagging tools

f an aquaculturist wants to undertake selective breeding in order to improve the performance of the species under culture, it is necessary to have all components of the life cycle under direct control. For some species it has been necessary to obtain young animals for stocking by collecting them in the wild since reliable means of producing young in a hatchery have not been developed. On other cases wild brood stocks are obtained because we do not have the knowledge required to grow fish to adult size in captivity or, more often, the cost of growing and maintaining brood fish may be too high.

H

Expressing eggs from a female rainbow trout

owever, the most successful aquaculture species like cycle from egg through adult is controlled by the aquaculturist. Each aquaculture species requires certain conditions for reproduction. These conditions vary widely. For example, some species spawn in fall or winter, some in spring, and some spawn almost continuously. The key to inducing spawning may be changing temperature (such as falling temperatures late in the year or rising temperatures in the spring), increasing or decreasing the amount of daylight present (also known as photoperiod) or a combination of the two. These types of environmental stimulus cause changes in the hormone activities within aquaculture species and lead to the development of eggs and sperm and, finally, induce the behavioral activity that accompanies the actual spawning act.

Using ultrasound to look at the development of the ovaries in a broodstock brown trout

Many aquatic species broadcast their eggs and sperm into water. The fertilized eggs will become members of the plankton community. Upon hatching the larval animals may continue to swim about in the plankton until they grow sufficiently large to enter the benthos or nekton community. This type of reproductive scenario is typical to shrimp, crabs, lobsters, oysters and certain types of fishes (red drum and striped bass). More specializes reproductive modes are used by many of the species of aquaculture interest.