Some important commercial fishes
Exercise 2. Read and translate the text.
TEXT 2
Exercise 1. Read and memorize the words from the text below:
| сold-blooded, adj | холоднокровный |
| backboned, adj | позвоночный |
| gill, n | жабры |
| limb, n | конечность |
| fin, n | плавник |
| tubercle, n | бугорок |
| scale, n | чешуя |
| catholic, adj | широкий, многогранный |
| alter, v | изменять; менять |
| feed, v | кормить |
| weed, n | водоросль |
| mud, n | грязь, ил |
| crustacean, n | ракообразное |
| mollusk, n | моллюск |
| spawn, v | метать икру, нереститься, нерестовать |
| ascertain, v | выяснять, устанавливать |
| commercial, adj | промышленный |
| genus, n | род |
| distribute, v | распределять, раздавать |
Fishes are cold-blooded, backbonedanimalsadapted to live in water,breathing by means of gills and having limbs represented by fins or rudiments of fins. The skin is usually covered with scales, but these may be replaced by bony plates or rough tubercles and rarely the skin is entirely naked. The scales vary greatly in size and structure among the species.
Whatever the nature of fish's diet it is essential that it should contain the following ingredients: water, minerals, fats or carbohydrates, proteins and vitamins; water makes up about 75 per cent of the body weight of fish. Nearly all fishes are catholic in their choice of food, and many alter their habits as they age and with the seasons.
For convenience fishes are classified according to their main methods of feeding in the adult age: 1) plankton feeders, 2) weed eaters, 3) mud feeders, 4) feeders on insects, crustacea, worms and molluscs, 5) fish eaters, 6) parasites.
All fishes have their definite spawning seasons. The majority of fishes spawn in spring or at the beginning of summer but there are also fishes which spawn in other seasons.
Approximately 12,000 distinct species have been ascertained by scientists, yet about 15 per cent of these are regarded as fishes of commerce. And among the common commercial fishes the following species may be mentioned as the most important commercial fishes, on account of their abundance, high productiveness and high food qualities.
The herring family. In productiveness none exceed those of the herring family numbering more than 150 species distributed over the greater part of the earth in both salt and fresh water, which contribute more to the support of the human race than any other family of fishes.
The cod family (cod, haddock, hake, and others) includes about 140 species. They are distributed chiefly in the north temperate zone. These fishes are marketed largely in the fresh state and preserved by salting both dry salted and pickled.
The family Salmonidae includes salmon, charr, trout (lake trout, brook trout, rainbow trout) and others. Some of them are anadromous. The most important members of the family are five species of salmon belonging to genus.
The mackerels and mackerel-like fishes (including tunas) numbering 60 species are widely distributed. They are highly praised for food in fresh, salted and canned state.
Exercise 3. Answer the following questions:
1. How can you describe fish biologically?
2. What is the skin of fish covered with?
3. What should fish diet contain?
4. Do fish alter their habits during the life?
5. When do fishes have their spawning seasons?
6. How many fishes are ascertained as fishes of commerce?
7. What fish family is the most numbering?
8. How many species does the cod family include?
9. What most important species does the family Salmonidae include?
10. Why are mackerel-like fishes praised so highly?