WEEK 3: IMPORTANCE AND PRESERVATION OF FISH

                                  WEEK3:

TOPIC:   IMPORTANCE AND PRESERVATION OF FISH

Specific Objectives: By the end of this lesson, students should be able to:

1. State at least four uses of fish and fish products.

2. Mention two methods of fishing.

3. Enumerate five methods of fish preservation.

4. List two risks factors in water and fish farming.

                        IMPORTANCE / USES OF FISH

1. Provision of food: Fish and their products serve as a very important source of animal protein. They are very nutritious and can be prepared as delicious of various forms. They contain many essential nutrients including vitamins and minerals.

2. Source of Animal feed: Fish by products can be processed into fish meals which can be used to supply or supplement animal feeds which provide protein requirements of farm animals.

3. Source of income: Fish and their products are important sources of income since they generate money when sold.

4. Medicines: Fishes have medicinal value example cod liver oil which is a fish product helps to maintain a healthy condition. It also helps in the treatment of certain heart and pulmonary diseases.

5. Provision of  raw materials for industries e.g leather: Certain fish products such as from cartilaginous fish e.g shark and other aquatic organisms e.g crocodile make good raw materials for leather used in leather manufacturing industries in the production of  belts, bags, shoes etc.

Also oysters contain parts that can be used locally to produce beads and other form of jewelries.

6. Aesthetics: People like to have a fish pond or aquarium in their homes for pleasure and enjoyment.

7. Articles of ornament: Some fish parts are treasured as articles for decoration and jewels. Shark teeth, shells, scales have been used for making necklaces and other decorative items.

8. Fish oil: Is used for various purposes e.g whale oil is used for heating and lubrication. Fish oil is also used for making soaps, candles, drugs, paints, wax etc.

9.  Glue and Fertilizer: Fish bones are used in making glues and fertilizers.

10. Buildings: Shells of oysters and periwinkles are mixed with cement and sand to make the walls of buildings stronger.

                               METHODS OF FISHING:

There are good and bad fishing methods. The bad fishing methods should not be used. 

Good Fishing Methods Include:

1. Nets: Involves use of nets of right mesh size for cropping of fish. This is the most efficient fishing method because a net can catch many fishes. Nets are made of fine cotton or nylon. A canoe is necessary while using a net. The nets are held by fisherman standing in a canoe or ship; and thrown into the water to enclose fishes which are then dragged into the canoe. The different types of nets include: (a) cast and throw nets, (b) lift nets, (c) seine nets and (d) gill nets.

2. Hook and line/Rod and line: This uses hook, rope, twine (line), the sinker which is a heavy object that makes hook stay below the water. A bait is also attached to attract the fish. Examples of baits: small fish, red soap, groundnut cake. Hook and rod are similar except that the hook and line uses more hooks.

3. Fish traps: These are usually woven from bamboo, cane, raffia, oil palm or wire mesh.

 They are of two kinds:

(a) They are “v” shaped traps and

(b) Triggered trap - Is baited with some food.

 As the fish approaches the bait, a delicate triggers set off, which causes the door of the trap to close behind the fish.

4. Fences: Shallow portion of water are screened with fences, made of raffia or oil palm fronds, bamboo etc. so that the fish can enter the enclosed area at high tide. When the water is reduced at low tide, the fish cannot escape.

5. Wounding methods/Impaling: Fishing gear can be used to wound the fish and then catch it. They cannot escape when wounded. The wounding equipment include: spears, arrows, knives and hooks.

6. Fish baskets, pots and gourds: Some fishermen clay pots, gourds and baskets in water to catch the fish which enter them.                                                                                                            

                                  Bad Fishing Method:

Bad fishing method includes:

1. Use of poison: This entails the introduction of chemicals like Didimac 25 and Gammalin 20 into the water which is harmful to both fish and cause harm to people eating such fishes. Similarly, the use of parts of toxic plants stuns the fishes.

2. Use of explosives: Under-water explosives are denoted stunning fish which float and packed up. Examples of explosives are dynamite and gun.

3. Draining of water: Involves draining of whole water in pond which lead to total cropping of fishes.

4. Electric stunning: This involves passing an electric current into the water, thereby stunning which swin by.

METHODS OF PRESERVING FISH:

 Preservation of fish is very important to avoid fish spoilage. This includes: salting, drying or smoking, refrigeration or freezing, canning, fish meal.

1. Salting: Common salt is rubbed all over the body of the fish or fish could be soaked in salt water. The fish is then dried in the hot sun. The sun prevents the activities of micro-organism to avoid spoilage of the fish

2. Drying/Smoking: Is done to remove water from the fish and thereby  prevent spoilage by micro-organisms. The fish is spread on wooden trays or wire guaze and exposed either to the sun or to a fire for smoking. Smoked fishes are kept for a long time and they are very tasty.

3. Refrigeration or freezing: This involves storing the fish at a temperature below 0⁰C which renders bacteria activities inactive. Deep freezers and cold rooms are used for this purpose.

4. Canning: This is the most scientific method of fish preservation which is required skill personal. It involves packing the fishes in air-tight cans under strict hygienic conditions, as in sardines. Fish stored in this way can stay long without spoilage and air is excluded from the can.

5. Fish meal: Small fishes/fish parts are dried and ground into powder (fish meal). This serves as important component of livestock feeds.

RISK FACTORS IN WATER AND FISH FARMING:

1. Contamination of water with chemicals.

2. Contamination of fish with chemicals.

3. It is capital intensive for large scale fishing.

4. Over stocking may lead to contamination.

5. Untimely death of the fisherman especially when he is not expert in using one of the unusual   methods of fishing such as use of explosives or electric stunning.

General Care of Simple Fishing Tools:

1. Wash and dry after use.

2. Oil or grease the metal blade to avoid rusting.

3. Clean after use.

4. Store in a cool and dry place.

5. Blunt edge of tools should be sharpened with the aid of the file.

6. Replace worn-out parts.

                      Fish Products:

1. Fish oil. (2.) Fish meal. (3.) Fish scale. (4.) Fish bones. (5.) Leather from fish.

Evaluation Questions: Answer the following questions:

1. State at least four uses of fish and fish products.

2. Mention two methods of fishing.

3. Enumerate five methods of fish preservation.

4. List two risks factors in water and fish farming.