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Fishing Technology

Principles of fishing

  • To have a good catch.
  • To employ a minimum number of manpower for a good harvest-
  • The amount of investment in fishing will be always less in comparison to output. 
  • Use of sophisticated gears which will in turn replace the old model’s gears.
  • To always maintain a balance between the number of fish caught and the number of young fish entering the population.
  • To reduce overfishing.
  • Less wastage of fish during fishing.
  • Fishing during the definite season and banned during the spawning season.

Fishing gear

Fishing gear refers to any form of equipment, implement, tool, or mechanical device used to catch, collect or harvest fish.

Types of fishing gear

All gears are classified into basic two types-
  1. Active gear: The gear which moves in the way of fish to capture it. The gear is used for instant capturing. Active fishing gears consume more energy during fishing. More productive than the passive type of gears. Examples – Trawl net, purse seine, cast net, Trawl line, hooks, etc.
  2. Passive gear: Passive gears are those which are left in place for a period before retrieval. They may either attract fish using bait or may passively wait for a fish to swim into a net or trap. Examples of passive gear are gill nets, longlines, traps, and pots.
There are mainly four types of fishing gear, such as-
  1. Nets
  2. Traps
  3. Hooks
  4. Spears and harpoons
1.  Nets
Based on setting  nets are four types such as-Based on fishing techniques nets are four types-
a.Cast netSeine net
b.Stake netGill net
c.Drag netDip net
d.Barrier netBag/purse net
2. Traps
Traps are mainly two types.
  1. Natural traps
  • Bush/Biosh trap
  • Barrier trap
  • Barrier with mud
  • Fence trap
  1. Artificial traps
  • Bana trap
  • Box trap
  • Tubular trap
3. Hooks

It is three types. such as,

  • Hand line 
  • Longline
  • Shortline
4. Spears and harpoons

Spears, Harpoons, ek kata, tin kata, etc.


Net is a meshed structure of indefinite shape and size, composed of one yarn or of one or more systems of yarns Interlaced or joined (ISO, 1974). 80% of exploited fish are captured by net, and 116 types are available in Bangladesh.

  1. Seine net
  2. Stake net
  3. Drag net
  4. Cast net 
  5. Gill net
  6. Drift net 
  7. Barrier net
  8. Trawl net 
  9. Bag/purse net and Others
1. Seine net 

A Seine net is a very long net, with or without a bag in the center which is set either from the shore or from a boat for surrounding a certain area and is operated with two (long) ropes fixed to its ends (for hauling and herding the fish).

More than 50 are identified in Bangladesh according to FAP (Flood action program). Some local names of seine net: Angta jal, Daljal, Chella jal, Dara jal, Dhop Jal, Jangla jal, Gulli jal, Fadi jal, Kochi jal,moi jal, thole jal, etc.

Based on the structure:

  • Seine net without a bag (Angta jal, Bhesha, Gulli Jal, Cheli jal, Dal jal, Choto ber jal) 
  • Seine net with bag (Jagat ber jal, Kamba vala jal)

Based on operation techniques:

  • Shore seine net(without bag)
  • Boat seine net (with bag)


  • Rectangular in shape.
  • The length is higher than the width 
  • Mesh size varies from 4-9 cm depending on the fish species to be caught
  • Two strong ropes are used at the upper and lower end.
  • Floats are attached with head rope (float line) 
  • Floats may be made of bamboo, sola, or wood 
  • Both natural and artificial yarn is used. Twisted nylon or polyester yarn is used.
  • Sinker may or may not be present on the sinker line.
  • Sinkers are earthen or broken bricks or metals.

Materials used and the making of nets

  • To make this net troop polyethylene, polypropylene, and polyethylene chloride chemicals, nylon thread, floats of sponge, and a sinker are used.
  • Both artificial and natural twines are used in the net.
Mode of operation 

The net is operated by ropes attached to the end of wings which are used for hauling and for herding the fish. They are usually operated in Coastal or shallow water bodies.

Seines that are operated from the boat are called boat seines. Danish seine is a well-known boat seine. It is operated on the bottom of a single boat, consists of a bag, and is used for the catch of large fish Species such as- Rui, catla, Shol, Boal, pangas, silver, etc. Its mesh size is larger. 

The Seine operated from the shore is called a shore seine net (without a bag). It consists of a float and sinker. All types of fish are caught by this net. In Bangladesh, these nets are mainly used in freshwater and marine waters.

Target Species 

All types of fish are caught. Mainly demersal species, less frequently for pelagic species. 

Water Area

Seine nets are operated both inland and in marine waters. The surrounding and catching area depends on the length of the seine and the hauling lines. The seine nets are used in marine waters, on the continental shelf, from the coast down to 500m, and are very common everywhere, lakes, large rivers, ponds, etc. 


This net is mainly found in Bd, India, Pakistan, Sri Lanka, etc.

2. Gill net 

A gill net is a wall of netting that hangs in the water column, typically made of monofilament or multi-filament nylon thread. 44 different types of gill net are identified in Bangladesh. 

Some gill nets-Chandi jal, current jal, khaira jal, koi jal, tana jal, ainapata, bachan, bariam, bhol, batta, chapila, chatka, fash jal etc.

Types of gill net

Based on the method of operation(use) of the gill net, it is divided into three groups- 

  • Drift gill nets
  • Set gill net
  • Encircling gill nets. (Estuary, sea) (taposhi, rani, mouri, sardine, shark)
Based on the setting of different water depths, gill nets are three types. such as-
a. Surface water gill netb. Mid water gill netc. Bottom water gill net
Water bodyRiver, beel, haor, baor, floodplain, seaRiver, beel, haor,  baor, floodplain, seaRiver, beel, haor,  baor, floodplain, sea
TwinNylon or polyester  Nylon or polyester Nylon or polyester
Fish caught Puti, tengra, Boal, koi, shing,kholisa, magurRui, mrigel, shol, boal, pangas, poaPelagic fishes such as- shing, magur, koi, shol, pangas, boal, hilsa


  • Rectangular in shape 
  • The length is higher than the width
  • Mesh size depending on the fish species to be caught 
  • Use with the help of a bamboo stick and set in different water depths.

Materials and methods

To make this net nylon fine thread and coarse nylon thread art sinkers and earthen sinkers are used. 

Mode of Operation
  • To operate this net 1 or 2 persons and 1 boat or donga are needed. The net is tied by two poles and the sinkers help to sink the net about the bottom of the channel.
  • Drift gill nets are operated in the surface layers and drift with the current either separately.
  • Set gill nets are fixed to the bottom or at a distance above the bottom using anchors or ballast.
  • Encircling gill nets are operated in the surface layers in coastal areas. After encircling the fish, noise, and other vibrations are used to drive the fish toward the nets so that they are gilled or entangled.

Target Species

  • Many fish species are captured in the coastal region and deep sea. Such as- Ilish, poa, pangus, persa, Bhetki/coral, ayer, sonali bata etc.
  • Some species are caught in the river/floodplain. such as-Boal, catla, Tengra, Bata, chapila, puti, ayer ,rui, pabda, Ilish etc.
  • Some species are caught in ponds and rice fields. Such as- Shing, Mrigal , Magur, tengra etc.

3. Cast the net

A cast net is also called a throw net. It is a circular net with small weights around the edges. These are conical nets and bag-like structures. A strong cord is attached to the apex of the umbrella and several lead or iron weights are fixed along with the margin that is the sinker. The cast is used for the fulfillment of family demands. This simple device is effectively used for catching fish for thousands of years. 

17 different cast nets are identified in Bangladesh –

Bachari jal, Pheka jal, Jhaki jal, Rekh jal, chhatki jal, chitta jal, Dhang Jal, Teorea Jal, Khapla jal, betka, bhumri, chootika, dhundi, dool, jhanki, kheoa jal, utar jal etc.

Cast nets are 2 types 

  • Hand cast net 
  • Boat cast net 

Materials use and making of the net

A strong cord, sinkers, nylon thread, color (pigment), etc. are needed for making khapla jal. Its mesh is (2.58-10)cm.

A cast net is made up of 3 parts:

  • The upper section (net band)
  • The middle section (a conical-shaped net mesh)
  • The lower section is weighted. 

Mode of operation 

Fishermen throw the net full spread over the waters keeping the long rope in their hand. The net sinks to the bottom and the circumfluence closes due to the weights attached to it. Then it is pulled out of the water using a cord and caught fish.


This net is mainly found in Comilla, Dinajpur, Jessore, Potuakhali, Rangpur, Faridpur, Noakhali, Barisal, pabna, Rajshahi, etc.

Fish caught

Rui, catla, mrigal, chela, koi,  magur, pangas, chingri etc. Almost all the fishes are caught by this net in ponds, rivers, haor, baor, and other shallow waters.

4. Dip net/Lift net (chaki Jal) 

Lift nets also called lever nets, are a method of fishing using nets that are submerged to a certain depth and then lifted out of the waters vertically. The nets can be flat or bag-like shaped. It can be hand-operated, boat-operated, or shore operated. More than 30 nets are identified in Bangladesh. They are-Bhael, bel, channi, dharma, chhai, hathbauli, kharajal, naokajal, bhesal, pona, ghuchoin, jali, heda, kechki, khall, Pelon,  tar,  chhoki, honcha, hati, khadra, langia, shib, tak, tani, veur, bheel, sitki etc.

Dip nets are 3 types:

  1. Hand Lift net: it is used to catch fish in shallow water bodies against the water current. It is used for fishing mainly in the hill region and running water. The size of the net is small. It is used in haor,baor, floodplain, etc. This net fulfills the family’s needs only.
  2. Boat lift net: it is used commercially. It is used in the deep sea attached to the boat. 
  3. Set lift net: It is placed in the water Bank and is generally made up of bamboo. The fish is filtered from the water.


  • Rectangular or triangular or circular with a handle made of bamboo or steel.
  • The frame is also made of bamboo or steel.
  • The handle can be ranged from 1-12 meters long.
  • It is made of a fine mesh size mosquito net. 
  • Twine: Nylon thread, both Natural or artificial (monofilament or polyfill ament).

Mode of operation

At the time of fishing, this net is thrown in the waters and it gets up in a determinate time and collected fish. A drowned net gets up from the water and it is called a haul. The net is operated from a boat or bamboo-made char and bank of water area. only one person can operate this net.

Fish caught 

This gear is usually used to harvest punti, chapila, chela, tengrea, koi, shing, shol, khalisha, magur, chingri, small indigenous fishes, etc. 

5. Drag net (tana jal)

Drag nets are a simple way to catch fish and require few tools as well as some common sense in practice. It is a mono-filamentous rectangular net. Thick nylon thread is attached to the apex of the net. Most of cases earthen sinkers are used.

13 nets are identified in Bangladesh such as-tana jal, badai jal, moi jal, Kathi jal, teori jal, Gulli jal, ber, anguta etc.


  • Rectangular in shape, length is higher than width.
  • Nylon thread (artificial and natural twist).
  • Synthetic floats and earthen round sinkers are needed. The sinkers are small rounded earthen plates containing pores at one side which the thread of net passes.

Mode of operation 

To operate this net 1 or 2 people and one craft or donga are required, one side of the net is kept on the bank and another side with the boat is dragged to the bank and caught fish. In Shallow water bodies, two-person pulls the bamboo poles on both sides and catch fish. 

Target Fish

This gear is used usually used to harvest bottom-dwelling fish, chingri, bele, baim, poa, fish seeds, punti, etc.

Difference between drag net and Seine net 
DragnetSeine net
Size is smaller than seine net The size is larger than the dragnet
Need less manpower to conduct Need more manpower
Used for fishing in shallow water bodiesUsed for fishing in both shallow and deep waters
Used for personal or family needUsed for commercial fishing
Floats and sinkers are used only in bigger onesEvery seine net has floats and sinkers
For collecting fish, the rope of both poles drags on the surface, A defined place encircled and collect fish by pulling the net eventually 
Need less timeNeed more time
6. Bag net

Bag nets are one kind of net that is used for fishing. Based on the types and nature of the water body and the use of the net. bag nets are 3 types-

  1. Scoop net: oval, circle, or triangular. The handle is made of bamboo. Twine natural or artificial nylon.

Use: the fish is collected by holding the handle in the shallow water slowly and taking the net up after some time.

  1. Skimming net: it has 2 mouths. Between both mouths, a rope is fitted which is used to control the net. When the rope is loose, the mouth of the net opened. After a few moments, the rope pulled and the mouth closed. Thus fish are caught. It is oval, brick sinkers are used in it. Both are nylon threads. The net is set in the running water with the help of a boat. Then it is placed by the length of the thread at different depths of the water. 
  1. Scarp net: conduct from the boat but the net is long and v-shaped. The handle and frame are made of bamboo and the twine is nylon. 

Use: used for both shallow and deep water. Conducted by hand from the boat.

7. Trawl net

Trawl nets are funnel / conical-shaped nets with extended wings at the opening that are towed off the vessels. Trawl nets are responsible for the greater portion of our national fish and shrimp captured. 

Based on the shape, bag nets are of two types-
  1. purse net/crap net
  2. Fixed purse net /Trawl net

These are the type of bagnet used in the trawler, so it is called trawl net. This net is used in the sea to catch fish. The end of the net is called the cod end. It has two Wings on both sides. There are two ropes on both sides which are used to control the net. A Trawl net is used to collect fish from the surface. Many fishes are collected using a Trawl net. 

Based on the position in the water column where they are operated, trawl nets are two types. 

1. Midwater trawl net

  • Many plots are used. Fishes are captured in the middle water. 
  • A lever is used to carry out the fish full net. Its mouth is opened and kept open for 10 to 20 minutes in the sea and then the net is pulled.
  •  If the fish density is high, then three to six times the net is drowned in the water for 24 hours. 
  • Two trawlers are used to operate the net. The net is thrown into the water and the ships pull the net to get fish. Fish Finder is used to detect fish schools. The net is pulled between the fish school.

2. Bottom water trawl net

  • It is oval or funnel-shaped. Used for bottom trawling. 
  • lead is used as sinkers and artificial twine are used. 
  • The mouth of this net is very large and a rope is used to control the opening. 

In the case of Bangladesh, mid-water trawl nets are mainly used in marine waterbody.

Name of some trawl/fix purse net

Atan jal, behundi jal, boga jal, behuti jal

Mode of operation 

To operate these nets there are four basic requirements a vessel needs to have: sufficient power to tow the net, a mechanism to hold the mouth of the net open, a system of wines to connect the net, and the gears to the to towing mechanism for casting and hauling the net.


Nylon thread, rope, bamboo, pork, etc.

8. Stake net

A stake net is a kind of fishing net, consisting of netting vertically hung on stakes driven into the ground, usually with special contrivances for entrapping or securing the fish. It is rectangular. Its length is 6-12 meters, width is 3-36 meters, and mesh size is 1.25-2.50 cm. Look like a gill net but stakes are used to fix the net. Generally used in tied areas to collect small fish. Nylon poly filamentous threads are used.

In Bangladesh, 12 types of stake nets are found. They are- Attana jal, baro jal, bhairabjal,  bhoro jal, bundhjal, chor pata jal, khal pata jal, Kathi jal, khorchi jal, Khaw jal, versa jal, lakua phorda jal.

Materials use and making this net 

Bamboo poles, nets, nylon thread, and Ropes are needed for making this net.

9. Barrier net

A round barrier is created with a net to catch fish so it is called the barrier net. It is surrounded by an area, so fish cannot escape from that area. It can cover almost 1600-2000 meters of area. Its width is much less than its length. The width is only 3-4 meters. It is set on tied or floodplain areas. Every type fishes are found. 


Netting or webbing is a meshed structure of indefinite shape and size produced by interlacing or joining one or more systems of yarns. Most commonly used netting materials have diamond-shaped meshes which are either knotted or knotless.

Knotted netting

Knotted netting panels can be hand fabricated but are normally machine-made. Different types of knots are used in the construction of netting. The most popular knot used is the English Knot which is also known as the weaver’s knot or sheet bend. A reef knot is useful in preventing knot slippage. eg-Khapla jal

Knotless netting

Knotless netting means netting which is composed of meshes of four sides of approximately equal length in which the corners of the meshes are formed by the interweaving of the twines of two adjacent sides of the mesh.

The advantage of knotless netting is

  • higher mesh breaking strength
  • Low material loss due to the absence of knots
  • Lower weight and hydrodynamic resistance compared to knotted netting.

Floats and buoys

Floats are used to keep the fishing gear in the desired position and to maintain the desired shape during the operation. Buoys are attached to the fishing gear to show its location.


Sinkers are used in tandem with the floats to give fishing gears the desired shape, fishing orientation, and fishing position as in gill nets, lines, and seines; to keep the mouth of the gears vertically open and to maintain good ground contact as in trawls and to increase the sinking speed and vertical stretch of purse seines.

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