Fish Anatomy

1 – nostril

2 – spines

3 – lateral line

4 – dorsal fin

5 – caudal

6 – isthmus

7 – pectoral fin

8 – pelvic fin

9 – anus

10 – anal fin

1. Fins: Most fish have at least one dorsal fin, a caudal fin, an anal fin, a pair of pelvic fins, and a pair of pectoral fins. Often the first dorsal fin has hard, sharp spines, while the other fins have soft, flexible fin rays. The fin spines and rays are connected by a thin fleshy material that collects excess mucus. Some fish (trout, salmon) have a small fleshy fin.

2. Scales: Scales are flat plates that form the outer covering of most fish. In most fish the scales are bony disks developed from the under skin. Scales overlap one another like shingles and form a protective armor for the softer body beneath. They vary in size, shape and arrangement depending on the kind of fish. Sharks have sandpaper - like scales that are really modified teeth. Trout, salmon have delicate «deciduous» scales. Many fish have hard, rough scales (perch, rockfish).

3. Lateral line: Most fish have at least one lateral line. The lateral line is a series of small sensor organs used by the fish for detecting turbulence and pressure changes.

4. Gills: Gill is the breathing organ of many animals that live in the water. It does the same work as the lung of an animal that lives on the land. Fish breathe with gills. These organs are inside hollow places on each side of the body just back of the head, if you examine the throat of a fish you will see four or more slits which open to the outside. They are called gill-openings. In bony fishes the gills cannot be seen until the hard gill covers are turned back or removed. When a fish breathes it opens its mouth at regular time and draws in a mouth full of water. It then draws the sides of its throat together. This forces the water through the gill openings. The water passes over the gills to the outside. Valves in the mouth keep water from escaping through the mouth again.

5. Mucus: Fish secrete mucus from their bodies to protect themselves from parasites and disease and to help them "slip" through the water easily. It is important to remove as much mucus as possible by washing the fish thoroughly. Mucus tends to collect on the fins, near the anus, gill cover, isthmus, nostrils and under the pectoral fins.

6. Body form: Body form of fish vary greatly in shape. The different ways of living influence fish anatomy. There are fish which keep close to the bottom, other swim near the surface. A flat flounder lies on the ocean bottom, while a round, bullet – shaped tuna needs to swim efficiently to capture prey.

VOCABULARY:

Nostril – ніздря

Isthmus – перешийок

Pectoral – грудний

Dorsal – спинний

Caudal – хвістовий

Mucus – слиз

To influence – впливати

Spine - радіалія

I. ANSWER THE FOLLOWING QUESTIONS:

1. Do fish scales vary in structure and reproduction quality?

2. What fishes have rough scales?

3. What is a lateral line?

4. What is the function of mucus? Where does it usually collect?

5. What factors influence fish anatomy?

II. GIVE THE ENGLISH EQUIVALENTS TO THE FOLLOWING WORDS:

Навколишнє середовище, мул, впливати, плавати, сильний, здобич, морське дно, ловити, мати схожість, протилежний, слизький, зябра, дихати, спинний, форель.

III. TRANSLATE INTO UKRAINIAN:

1. The shark has sharp teeth with which it catches its slippery.

2. The powerful tail of shark carries a caudal fin.

3. Modifications in the anatomy of a plaice (камбала) have taken place under the influence of the environment in which they lived, i. e. the sea bottom.

4. The plaice does not swim upright as do other fishes, but lies on one side.

5. The plaice has an interesting colour pattern: one side of the body matches the ground, and the opposite side is whitish.