Application of Zoology
Fish farming is the practice where fishes are produced in the ponds for the commercial purposes. In other words, the rearing of fish in different types of water resources is known as fish farming.
Pisciculture is the practice of culturing fishes by employing artificial means and scientific techniques. Fish are the rich sources of protein, fats, phosphorus, vitamin A and Vitamin D. It has good taste and
easily digestible. Nepal is very rich in water sources in the form of rivers, ponds, lakes, reservoirs,paddy fields etc.
History: The history of fish farming in Nepal began from 1947 when fingerlings of Indian major carps were introduced in the country. Rainbow trout (Oncorhynchus mykiss) was introduced in 1968 and 1971 from India and in 1988 from Japan. There are about 217 indigenous and 15 exotic fish species in
Nepal.
Types of fisheries: Inland fisheries and Marine fisheries
Inland fisheries: Fish farming in fresh water. There are two types of inland fisheries in Nepal:
i. Riverine fisheries: fish farming in river systems.
ii. Lacustrine fisheries: fish farming in natural or man-made lakes.
Categories of inland fish farming: there are two main categories of inland fish farming:
i. Captured fisheries: It is done in natural habitat.
ii. Cultured fisheries: It is done in artificial conditions.
Types of fish farming or fish culture practice:
There are three types of fish culture practice:
1. Monoculture: In this type of fish farming, a single species of fish is cultured at a time. But it gives low yields as all the natural food and ecological niches are not utilized.
2. Polyculture: In this type of fish farming more than one species of fishes are cultured at a time. In this type of practice all the ecological niches (resources) of water bodies are utilized. In Nepal polyculture has been a common practice for Chinese carps and Indian carps. The following fish species are used for polyculture in Nepal: Labeo rohita (Rohu), Catla catla (Bhakur), Cirrhinus
mrigala (Nainy), Cyprinus carpio (Common carp), Hypopthalmichthys moltrix (Silver carp), Ctenopharyngodon idella (Grass carp), Aristichthys nobilis (Bighead carp) etc.
3. Integrated fish farming: It is the practice of fish farming with agricultural crops and other animals
such as fish farming with ducks, fish farming with pigs, fish farming with vegetables, paddy cum fish culture etc.
Types of fish ponds:
A fish farm consists of 4 or 5 types of ponds and each pond has specific purpose:
1. Segregation pond: This pond is required for separating the fully matured (2-3 yrs old/ 3-4 kg) male and female fishes called brooders before breeding season.
2. Spawning (Breeding) pond: In this pond male and female brooders are kept in the ratio of 2:1 (male: female) for breeding. These are provided with protein rich foods. After spawning, fertilization occurs then brooders are removed from the pond.
3. Hatchery pond: It is small pond (3m x 2m x 0.6 m) where eggs are hatched after 24-48 hours of fertilization into fish fries (very small fish after larval stage). A constant flow of water must be maintained. These fries are kept here for 2-3 weeks.
4. Nursery pond: These ponds are used for rearing fries for 1-3 month till they became fingerlings of 10-40 gm in weight. Wheat flour mixed with soyabean flour (5:50 ratio) used to feed the fry.
5. Stocking pond: These ponds are large, perennial and deeper (up to 6ft depth) used for the production of table fishes. Fishes are left for growth and prepare to stock. Manuring of this pond is done by both organic and inorganic manures.
Fish breeding techniques:
The fish breeding is usually carried out in a cement tank (size: 5m x 3m x 1m) which was treated with NaCl and filled with water to the level of about 50 cm deep. The male and female breeders were kept together in the same breeding tank for breeding with continuous flow of water.
a) Natural breeding: Brooders became sexually matured when milt comes from the male as it is
pressed on the stomach. Ripe females have soft, rounded bulging abdomen and reddish genital opening. Usually, one female is placed into a hapa with two males (1:2) to ensure fertilization. Breeding Hapa (small cage like rectangular or square net box placed in the pond for holding fish) can be placed into the source of flowing water so breeding occurs naturally.
b) Semi-artificial breeding: This type of breeding conducted in cement tanks with Kakabans (an artificial net like structure made from natural material like woven ropes, straw etc. where female fish lay eggs). In order to stimulate spawning, pituitary gland solution was injected in brooders.
About 10-12hrs after injection, the breeders spawned and scattered their eggs on the kakaban.
c) Artificial breeding: in this type fishes ae made sexually matured and allowed for ovulation. In this process pituitary extracts are used. The males from which milt could be pressed out by applying gentle pressure with fingers on the hind part of the belly are selected for hypophysation (removal of pituitary gland or hypophysis to extract hormones). The females are injected 2-3.5 mg/kg of pituitary extracts and males are given only 1 mg/kg of pituitary extracts. About 10-12 hr of injection, the spawning occurs otherwise the eggs are stripped. The milt collected from the male is poured over the eggs. The mixture is stirred immediately with a feather for 5-10 min. Now, the fertilized eggs are washed for 2-3 times with fertilizing solution then transferred to the incubators.
Some important cultivable fish species of Nepal
Indigeneous fishes: These are common native fishes cultured for commercial production: Bhakur, Rohu, Asala, Naini, Garahi etc.
Exotic fishes: These are imported fishes to Nepal such as Grass carp, Common carp, Silver carp, Bighead carp, Chinese carps etc.
Pond management
i. Soil: Pond soil must not be porous. The clay loam is used for the control of soil leakage.
ii. Water source: the perennial source of water is essential from spring, river or irrigation.
iii. PH: The PH of water must be optimum (PH 7-8). Acidity of water neutralized by using lime.
iv. Oxygen: Water must be aerated. Constant flow of water add oxygen for respiration of fishes.
v. Light: Activities of fries and growth of algae and other plants depends on light.
vi. Temperature: The optimum temperature of pond for fish growth is 20 -30 °C.
vii. Fencing: Fencing of pond is essential for protection against snakes, carnivorous fishes, etc.
viii. Manuring: It is done by using cow dung, compost or chemical fertilizers.
ix. Liming: Quick lime (CaO) is used which raises the PH of pond water and acts as anti-parasitic.
x. Feeding: Fish feed (rice bran, wheat flour, oil cakes) can used to increase fish production.
xi. Harvesting: Fish harvesting can be done for marketing by netting or by draining of ponds.
Cage fish culture: It is the practice of raising the fish in a large, submerged cage that can be used in a pond or lake or large perennial deep river or reservoirs. It is first started in Japan. And now introduced in Phewa, Rupa and Begnas lakes of Nepal. The size of the cage varies from 8 to 12 sq. m. and ideal depth is about 2 to 2.5 m. the outer (top) surface of the cage remains slightly above the water surface. The cage may be stationary or allowed to float freely in confined water reservoirs.
Advantages of cage culture:
- It requires less investment.
- Inspection of fishes and their feeding is much easier.
- It can be transferred from one place to another during emergency.
- Harvesting is simple.
Paddy cum fish culture: It is the fish culture practice done in paddy fields. It is common in China and Vietnam. It is also practiced in Nepal but not become so popular. Air breathers fishes like Chana, Clarias, Saccobranchus and minor carps are cultured and harvested along with the rice.
Integrated fish management: It is a new concept of fish farming practice which has been popular all over the world. In this practice, along the fish culture, duck culture, pig culture and poultry farming are generally done.
Importance of fisheries:
Nepal is rich in water resources so fisheries has great scope in Nepal. The major importance of fisheries
are:
i. As human diet: Fishes are the important constituent of human diet as it is easily digested and provides proteins, fats, phosphorus, Vitamin B12, Vit. B-complex, vitamin A, vitamin D.
ii. Source of income: Many people depend on fisheries for the source of income and livelihood. It offers great opportunity for self-employment and income generation.
iii. As cattle feed: The waste parts of fishes can be dried and ground to convert into fish meal and is used as artificial food for poultry, pig, cattle etc.
iv. Fish manure: Fishes which are unfit for human consumption and waste parts of fishes are used to prepare fish manure for the agriculture purpose.
v. Fish oil: the most important fisheries by-product is fish oil (liver oil and body oil) which are used in the treatment of vitamin deficiency or malnutrition.
vi. Fish skin: the skin of large sized fishes is used for the manufacture of shoes, handbags etc.
vii. Decoration: Several species of beautifully coloured fishes are kept in aquarium, tanks etc. for ornamental purpose.
viii. Games: Fishing is an important game for amusement of people.
ix. Biological control: several species of insectivorous fishes such as Chela, Puntius, Danio, Colisa, Gambusia etc. actively feed on eggs, larvae and pupae of mosquitoes and help to control them.
Note:
- Asla (Schizothorax spp.) and Sahar (Tor spp.) are indigenous and economically high value fish rearing in Trisuli and Pokhara.
- Rinbow trout (Oncorynchus mykiss) is imported from Japan in 1988 and being raised in Trisuli and Godawari. Trout needs cold, clear and oxygenated water.
- Fisheries research stations in Nepal are Fisheries Research Division -Godawari, Fisheries Research Centre- Pokhara and Trisuli, Regional Agriculture Station-Tarahara and Parwanipur etc.
Poultry Farming
Poultry farming is the rearing of the poultry such as chickens, ducks, turkeys, geese, pigeon, ostrich etc. in the farms for the commercial production of eggs and meat. Poultry farming helps to fight against the problems of malnutrition, poverty and unemployment.
In Nepal, poultry framing includes the raising of chickens for meat, eggs and manures. Chicken is the widely eaten meat in Nepal. Chickens farmed for meat are called broilers while those farmed for eggs
are called layers (egg-laying hens).
Improved breeds of chicken in Nepal:
1. American breeds:
- Single comb white leghorn: It is a good egg layer.
- Rhode Island Red: It is also a good egg layer.
- White Plymouth Rock (Broilers): It is a fast-growing breed for meat. It is a cross between
the White Cornish and Plymouth rock or New Hampshire.
2. Asiatic breeds: Brahma, Cochin, Langhan, Aseel etc
3. Indian breeds: Aseel, Ghagus, Basra, Chittagong etc.
System of poultry farming:
It includes: Incubation, Brooding, Rearing, Management and Feed.
a) Incubation:
- It is the process of development chick embryo inside the egg.
- The eggs for incubation should be fertilized, clean, not cracked and should not be more than 10
days old nor thin shelled.
- The eggs for incubation should be stored at an optimum temperature (15 to 19 °C) with their wider end up.
- In an artificial incubator, the eggs are incubated at the temperature of 37 to 38 °C. The incubation period of chick is about 21 days. (28 days for duck and geese)
b) Brooding:
- It is the process of taking care of one day old chickens in brooder.
- Constant warming should be provided until they can live without supplementary heat.
- In natural brooding, maternal care is done by foster hen by providing food and necessary
warmth to the growing pullets.
-Artificial brooding is done in a brooder box (size 1.3 m x 0.7 m) for keeping constant warmth to the growing pullet for about a month at the temperature of 35 °C.
- Every week the temperature should lowered by 3 °C until it comes down to 21°C.
- Proper care should be done for supply of feed, drinking water (3-5 times a day) as well as checking against the death of pullets.
c) Rearing:
- Pullets are female chicken under one year of age.
- Vaccination and sexing of pullets should be done before keeping them into the far.
- There are four different rearing systems of pullets:
i. Free range or extensive system: In this system, the chickens are let free during day and kept in the pen during night as done in the village.
ii. Semi-intensive system: In this system the pullets are kept in a small fencing land for pasture during the day and kept in hut during the night.
iii. Intensive system: in this system, pullets are kept in a room and required food is supplied.
This is a common system for commercial poultry farming. It is of two types:
- Battery or Cage system: In this system, single pullet is kept in a separate cage.
- Deep litter system: In this system, group of pullets are reared in a common ventilated
room with litter on the floor.
iv. Folding unit system: In this system, the pullets are kept in a small closed space and the site is changed every day. Thus, making them available a new ground for pasturing.
d) Management:
- It is an important aspect of poultry farming.
- It includes selection of site for farming, sanitation, preservation of eggs, marketing etc.
- The poultry pen (coops) should be established at open, dry, peaceful and sunny place.
- The pen has to be predator proof against fox, eagle, snake, rat and other predators.
- It should be provided with water channel and appropriate drainage system.
- Chickens of different ages should be kept in different houses.
- Lime spray should be done in the pen for the protection of chicks from parasites such as
tapeworm, roundworm etc.
e) Feed:
- Poultry feed is made by mixing different constituents like crushed grains (wheat, maize, rice), cakes (mustard), calcium (bones), green grasses, fish meal, vitamins, salts in different ratios.
- Special varieties of chicken are given feed rich in calcium and protein to increase egg
production and development of body muscles. Feed costs 60% of total cost of raising poultry.
Advantages of poultry farming:
i. Poultry farming offers a great opportunity for self-employment and income generation.
ii. Chicken meat and eggs are rich source of protein, vitamins, minerals, fats etc.
iii. Chicken meat is economical as compared to the mutton and pork.
iv. Poultry farming requires less capital investment and ensures quick returns.
v. Poultry farming helps to fight against malnutrition, poverty and unemployment problem.
vi. The space required is less when compared with livestock.
vii. By products and waste from poultry farming can be utilized in several ways: such as broken shells are used as a source of calcium in the chicken feed, feathers used to make quilts and pillows, the droppings of the chicken can be used as organic manures in the crop fields.
Disease and control:
- There are different types of diseases of poultry such as fowl cholera, fowl pox, coryza etc. which can lead to death of a large number of chickens.
- These diseases can be controlled by preventive measures like good management, proper nutrition,
timely vaccination of the newly born chicks.
- Administration of broad-spectrum antibiotics like sulfa drugs help in curing several diseases.
- Overcrowding of chickens, poor ventilation and dampness in poultry houses favor the spread of diseases.
- Newcastle disease commonly known as ‘Ranikhet’ caused mass death of chickens in two poultry farms in Morang district.
- Bird flu: Millions of birds have died from Bird flu or Avian Influenza (H5N1 virus). Avian virus is one of the major problems in poultry. Infected as well as non-infected poultry should be immediately disposed to spread the bird flu.
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