Fish Culture

Fisheries Resources

The principle source of protein for the peoples of Bangladesh is fish. The supply of 63 percent of protein in Bangladesh comes from fisheries. About 10 percent of the population is dependent on fisheries resources for their livelihood. The climate, soil and water of Bangladesh are very suitable for the culture fish throughout the year. So, fisheries resources have a great potential for its development. During present time, the production from fisheries sector started increasing due to the development, execution and extension of appropriate fish culture technologies. The production of fisheries during 1994-95 was 12 Lac tons. This production has been raised to about 24.40 Lac matric tons during 2006-2007. The shrimp culture has widely extended in the costal belt of Bangladesh and resulted in increased export at the satisfactory level. 

Though the production from the marine and closed water sources have increased satisfactorily, the production from the inland open water sources have greatly decreased. The production of Hilsa is very important among the open water fishes. The per capita consumption of fishes has decreased to 27gm from 33 gm during the last 10 years. Now the availabity of fish consumption per capita has been increased upto 46 grams. But the necessity of fish consumptions is about 50 grams. 

The Resources of Fisheries 

Bangladesh have wider fields of fisheries resources due to natural and environmental reasons. According to the characteristics of the water bodies the sources of fisheries may be classified into two categories resources these are:

 1.    Inland water.

 2.    Marine water. 

Inland Water

 In general, the fresh water and the water of semi-saline coastal area are known as inland water. The inland water sources in Bangladesh measures to 45 Lac 75 thousand 706 hectares. The inland water bodies of Bangladesh may be categorized into two sub-classes according to its size and structural composition, these are :

 1.    Inland closed water

 2.    Inland open water 

1. Inland Closed Water 

An inland fresh water which is bounded by dike or high land is called inland closed water. The area of inland closed water in Bangladesh in about 5 Lac 28 thousand 390 hectare. Fisheries may be cultured scientifically in these inland closed water. About 39 percent of the total fish production comes from the inland closed water in Bangladesh. 

2. Inland Open Water

 The comparatively large sized fresh water not within dikes or high land boundaries are known as inland open water. Rivers, canals, Haors, Kaptai lake and flood plain are in Bangladesh are classified as inland open water. The total area of inland open water in Bangladesh is about 40 Lac 47 thousand 316 hectare. Fish is not usually cultivated in inland open water. But the naturally grown fishes are frequently harvested from such water. More than 41 per cent of the country's fish production comes from the inland open water.

3. Marine Water

 The marine fisheries constitutes about 20 percent of total fish production in Bangladesh. The Bay of Bengal is on the south of Bangladesh. So many species and varieties of fishes and shrimps are found in the Bay of Bengal in large quantities. Mechanized boats and trawlers from marine water harvest the fishes. 

Causes of Reduction of Fisheries Resources in Open Water

 The production of fishers in open water has been reduced due to many natural and man made problems. The important causes may be summarized as follows: 

 1. Reduction of volume of water sources due to natural and increased of rate of siltation. 

2. Inappropriate irrigation and drainage plans and embankments.

 3. Indiscriminate harvest and destruction fish fries and fishes with eggs. 

 4. Drying of low land and Haors during the day winter season.

  5. Conversion of fisheries fields to crop fields.

 6. The natural habitat of fish movement and fish breeding are seriously  disturbed.

 7. Application of pesticides to the crop fields indiscriminately.

 8. Increased pollution of water due to disposal of toxic industrial wastes in the rivers.

 9. Catching small fishes by using a kind of net, which is prohibited? 

Plan of Developing Fisheries Resources

 Steps have been taken to conserve fisheries resources of the open water, to extend fish cultivation in closed water and to promote shrimp culture in semi saline coastal areas, besides, steps have also been taken for ensuring the expected fish production through integrated fish cultivation and management programmes.

Open Water

 The inland open water is the most important source of the fisheries resources in Bangladesh. About 41 percent of the total fish production comes from inland open water. For these reasons, programmes for releasing fish fries in open water have been taken for increasing the production of fish in an experimental way. Besides the following steps have been taken for the development of fisheries resources in the open water: 

1. The execution of the fisheries Act. have been strengthened so as to prohibit the use of illegal net and destruction of small size fishes.

 2. The leasing system of the water resource has been stopped. The leasing of 'Khas' government water resource on the basis of the long term production plan has been introduced instead of leasing on the basis of collection of revenue.

 3. The sheltered areas or 'Abhoy Asram' have been created to ensure free movement and breeding of fishes of specific and important place of water. Any sort of fishing has been prohibited in these special areas. 

Closed Water

 The fish cultivations have been extended in closed water through the development of appropriate technologies, involving more ponds under programme and through intensive training. The government agencies are setting demonstration ponds or fish farms for the extension of improved technologies. It has become possible to produce up to 10 tons of Rui fish per hectare of ponds under this programme, which has become a great hope for the country. The average production of fishes in ponds has increased from 1.5 to 3 tons per hectare due to the execution of these fisheries extension programmes. 

Coastal Water

 The cultivation of shrimp has greatly increased in the coastal areas during the last 4 to 5 years. The potential places of coastal shrimp culture have been identified. Programme for necessary infrastructural development, establishment of demonstration farms and hatcheries and farmers training are being implemented for the extension and improvement of ‘Bagda’ and 'Galda' shrimp culture. 

Integrated Fish Culture 

Steps have been taken by the government for integrated fisheries cultivation in the areas developed due to construction of irrigation, drainage, flood control, and other related infrastructure.

Fisheries Acts and Regulations 

Once upon a time, the tanks, ponds, rivers, canals, lakes, Haors, Baors etc. were full of fisheries resources. But the indiscriminate harvest of fishes, mass harvest of fish fries and female fishes with eggs, use of current nets and harvest 'Nala' and 'Jatka of without conservation of fish resources of the open water have resulted in serious deficiency of fishes in the country. In this context, it may not be possible to increase fish production unless the released fish fries are allowed to grow to a particular size. 

In order to overcome these problems "Fisheries Conservation Act 1950" was passed by the government in the year 1950. Later on, the Act was modified and revised in the years 1982, 1985, 1987, 1988 and 1995 to make it more adaptive as per requirement of the country. The major points of this Fisheries Act may be mentioned as follows:

1. The natural movement of the fishes in the rivers and canals cannot be hampered. 

2. Hunting or harvesting of fishes through the use of explosives, guns and arrow is prohibited. 

3. The natural habitats and breeding zones of fishes can not be disturbed by using poisons, disposing toxic industrial wastes or by any other way or ways. 

4. Without a view of cultivation, the fish fries of Rui, Katla, Mrigel, Kalibaush, Ghania, etc. measuring less than 23 cm cannot be harvested during July to December (Mid Ashar to Mid Poush). 

5. Harvesting of Rui, Katla, Mrigel, Kalibaush and Ghania of any size is prohibited during the breeding season. 

6. Harvesting of Shol, Gajar and Taki fries are prohibited in open water bodies from April to June (middle of Chaitra to middle of Jaisthya). 

7. Jatka is prohibited to catch to carry and to sell during November to May.  

8. Use of current net is strictly prohibited.   

9. Fine or jail or, both punishments may be given to the defaulters of the laws.

Besides, Fisheries Conservation Act, the following Acts and Regulations related to development fish culture are in vogue in the country.

 1. Pond Development Act. 1939

 2. Marine Fisheries Act. 1983

 3. Fisheries Inspection and Quality Control Regulations. 1983

 4. Shrimp Culture Act 1992.

 5. National Fisheries Principles 1998

 6. National fish strategy 

By an oder SRO no. 41 law/2008-20/02/08 Government has been prohibited to import, carry, culture, sell, receive or market, expose and possess any species of fish of piranha group.

Introduction to Fishes

 A fish may be defined as an vertebrate animal living in water having cool blood, and which perform respiration through gills and move with the help of different fins.  

Types of Fishes

 The fisheries resources of Bangladesh may be classified into 3 categories according to the characteristics of the habitats. These are_ 

1.     Fresh water fishes

 2.     Semi-saline water fishes

 3.     Saline water fishes. 

Fresh Water Fishes 

The fishes which grow in the inland closed and open water namely ponds tanks, rivers, canals, Haors, Baors, lakes, etc. are known as fresh water fishes. The examples of fresh water fishes are Rui, Katla, Shing, Magur, Puti, Koi, Taki and Boal. 

Semi Saline Water Fishes

 The water of the estuaries and rivers mouths are of the semi saline in nature. The fishes growing in such habitats are known as semi saline fishes. The examples of semi-saline fishes are Bhetki, Poa, Laitya and Coral. 

Saline Water Fishes 

The fishes growing in the salty water of coastal areas and in the Bay of Bengal are known as saline water fishes. The examples of saline water fishes are Hilsa, Rupchanda, Churi, Bele and Datina. 

The Characteristics of Cultivable Fishes 

Fishes having certain characteristics are suitable for cultivation in the ponds. The characteristics are the following: 

1. Rapidly growing and tasty.

 2. Have high nutritional value and tasty.

 3. Market demand and price is higher.

 4. Fish fries are easily available.

 5. May be cultured in a mixed manner.

 6. Can survive in a relatively unfavorable environment. 

 7. Resistance power of diseases is higher.

 8. Fish fries may be produced through artificial breeding.

 9. Fishes are not voracious. 

10. Fishes those eat supplementary feed. 

Fishes Suitable for Cultivation (Rui)

 Rui is basically a river fish of our country. However, Rui is very suitable for cultivation in the ponds. Rui is a very popular and tasty fish in Bangladesh. 

The fishes suitable for cultivation in ponds, among carp fish are Rui, Katla, Mrigel, Silver carp, Common carp, Grass carp, etc.

Morphological Characteristics:

 The head of the Rui is comparatively smaller than its body. The dorsal side is more convex than the ventral. The lips are thick, ridged and have two short barbles at the apex of the lips

Food and Feeding Habits:

 Rui fish take most foods from the mid layer of the pond water. It takes planktons as food. Rui fish likes zooplankton at fry, fingerling and young stages but takes phytoplankton and decomposed organic materials as natural common feed. 

Maturity and Reproduction:

 Rui can grow to a length of about one metre. It attains reproductive maturity in a period of three years. Under favourable environment, Rui fish release eggs in the month of mid April to mid July (Baishakh to Shraban months) in open water. Eggs may also be produced from Rui artificially. Rui does not release eggs in, closed water. 

Katla 

Katla is a rapidly growing fish and is very suitable for cultivation in ponds. Its original habitat in this country is the open water and rivers. The growth rate of Katla in the hoar, baors, rivers and canals is very satisfactory. 

Morphological Characteristics:

 The body is short and the head is comparatively larger. The mouth is wider and lightly curved upwards. The upper lip is thin but the lower lip is thick. The dorsal side is more convex than the ventral side. The colour of the dorsal side is dark gray, and lateral side is silvery white. The fins are blackish in colour.

Food and Fooding Habit: 

Katla mainly eat upper layer food of the pond. Katla basically eats zooplankton and sometimes may also eat phytoplankton

Maturity and Reproduction:

 Katla fish do not release eggs in closed water on normal condition. Its length may be 1 metre. It attains maturity within 3 to 5 years. A katla fish of normal size can produce about 15 to 30 Lac eggs. Under favourable condition katla lays eggs during mid May to July (Jaistha to Sravan months) in some specific rivers. Fries of katla may be produced in hatchries by' artificial breeding. 

Mrigel

 Mrigel is also a river fish of this country like Rui and katla. Mrigel is very suitable for culture in ponds. It is a rapidly growing fish.

Morphological Characteristics: 

The body of Mrigel is longer and straight. The upper jew is slightly curved downwards. There are two short barbles at the tip to lip. The dorsal side is grey, while the lateral and ventral side is silvery white. 

Food and Food Habits:

 Mrigel is a bottom dwellers. It takes food from the bottom of the pond. Mrigel likes to eat microorganisms, zooplankton and organic materials found in the bottom mud the ponds. 

Maturity and Reproduction:

 The length of Mrigel is 1 metre and weight 8 to 9 kg. It attains reproductive maturity within two years. A female matured Mrigel can produce 1 to 5 Lac eggs. It lays eggs during the month of mid April : to mid July (Baishakh to Sraban months) in specific rives, It dose not lays eggs in stagnant water, Fries may be produce by artificial breeding. 

Silver Carp 1:

 Silver carp originally comes from China and Russia. Silver carp may be cultured with native carp successfully. Silver carp is a rapid growing fish. 

Morphological characteristics :

 The body is covered with silvery white scales. The abdominal side is more convex than the dorsal side, The middle portion of the fish is wide which gradually narrowed towards the tail. The colour of the dorsal side is slightly grayish. 

Food and Food Habit : 

Silver carp take the food from the upper layer of the pond. Generally it takes the phytoplankton as food, Silver carp also eat decomposed aquatic plant. 

Maturity and Reproduction :

 Silver carp does not lay eggs in the pond. They lay eggs in river under normal condition. However, artificial spawning may be done and fishes may be produced in hatchery. 

Grass Carp 

The original habitat of Grass carp is China a Russia: It is suitable for mixed culture with other carp fishes. Grass carp can eat aquoas weeds and small plants and keeps the environment of the pond clear. 

Morphological Characteristics;

 The shape of body of Grass carp is like Mrigel, however there is no barbles on the lips of Grass carp like Mrigel. The dorsal fin in smaller, the colour of the dorsal side is slightly greenish. Head is smaller comparatively than the body. 

Food and Food Habit: 

It can eat in all layers of pond. Grass Carp likes soft aquoas weeds and green grasses. 

Maturity and Reproduction: 

Grass carp does not lay eggs in closed water. It releases eggs in rivers, canals and open water. Artificially spawning may be done and fries may be produced in hatcheries. 

Common Carp

 Common Carp is known to be originated from the temper it region of Asia namely in the south China.There are two types of Common carp found in Bangladesh. These are Carpeo and Mirror carp.

Morphological Characteristics:

 The body of Common carp is flat. The head is comparatively smaller than the body. The body of Carpeo is covered with redish scales. There are few rows of scales on the dorsal side of Mirror carp. The colour of the dorsal side is light brown, the abdominal side is golden in colour. The scales is relatively larger than the carpeo. 

Food and Food Habit: 

The Common carp is bottom dwellers of the pond. They dig hole at the bottom of the pond and take food like insects, micro-organisms as available in the mud. It also eat decomposed organic materials. 

Maturity and Reproduction:

 Common carp lays eggs ponds. It lay eggs two times in a year, once in winter season and the other in summer or rainy season.