MATERIALS REQUIRED FOR CAPTURE IN FISHERY

 

CHAPTER ELEVEN

MATERIALS REQUIRED FOR CAPTURE IN FISHERY

11.1                        FISHING METHODS                                                                                             

Fishing method means how the fishing gears are used. There are different method uses to catch fish. The majority of method has an adverse effect on the marine environment in term of by catch damage to the seabed and negative effects on the marine food web.

Fishing method is classified into two main categories

     i.               Passive fishing method

   ii.               Active fishing method

1.         PASSIVE FISHING METHOD:- This is a fishing device consisting of gear where the gear must seek out the gear in order to be caught. Such the fishing gear is 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 traps. These gears are most suitable for small scale- fishing and are therefore often the gear type used in artisanal fisheries.

        Some passive fishing gears are often referred to as stationary fishing gear. Stationary fishing gears are those anchored to the seabed and they constitute a large group of the passive gear however some moving gears such as drift nets may also be classified as passive gears, as fish capture by those gears also depend on movement of the target species toward the gear. Example passive gears are gill net, longlines, pot and traps, hook and lines.

2.         ACTIVE FISHING METHOD:- A fishing device consisting of gear where the gear must seek out the fish to catch it. These methods are especially suitable for sampling large proportion of the whole fish stock or large number of fish. The term ‘active’ means that the fishing gear is dragged through the water by human animal or engine power.

11.2                                                 FISHING GEARS

 

Fishing gear means the apparatus used for taking out fish from a body of water. Also it can be expressed as the tool with which aquatic resources are captured. Fishing gears can be divided into five main categories, the first three are must commonly used in Nigeria

1.         Nets (including trawl nets and dredges)

2.         Hook and line

3.         Traps

4.         Grappling devices

5.         Stupefying devices

 Of these gear types, trawls nets and hook and lines are the most commonly used.

1.         NETS:- Net come in many sizes and shapes, some are used actively (movable, dragged through the water) while other are used passively (fixed, allowing fish to swim into them). Common types of nets include gill net, trammel nets lift nets, cast net, trawl net, dredges,  beach seines and purse seines.

a.          GILL NET: A net wall with its lower end weight by sinkers (for heavy net as in drift gill net) and the upper end raised by floats is set across the path of migrating fish. Fish trying to make their way through the net wall are gilled or entangle in the mesh.

b.         LIFT NET:- A sheet of net usually square but many sometimes be conical is stretched by several rods, ropes or a frame and is set either at bottom or in mid-water for some times and than lifted to trap the fish swimming above it.

c.          SEINE NET:- A bag shaped net with two wings normally the wings are larger than those of trawl nets the net is pulled towards a stationary boat or onto a beach.

Materials for making seine net

Rope  ( ii) netting  (iii) float/cork  (iv) Twine/ string  (v) sinker/weight/ lead (vi) knife (vii)mending needle

Disadvantages of seine nets

1. It require skill to operate

2. It is labour intensive and cannot be operated by one person.

3. It is expensive to construct.

d.    BAG NETS:- It is a conical in shape with wide mouth without wings. The mouth is fixed on a bamboo. The nets are used with the help of two boats.

e.     CAST NETS:- It is a circular and cone shaped net. It is spread from the edge of water. Its circumference is attached to leadline while its centre is attached with a rope. The net assumes shape of umbrella when it is spread on the water. When the net sinks to the bottom it is pulled and fishes are collected.

f.     TRAWL NET:- Trawls are towed nets that usually consist of a frame with a net bag attached that is pullet form a boat to collect fish and other marine life. Most trawls are dragged along ocean bottom, but may also be used in mid-water to capture certain species. Bottom trawl can do considerable damage to the ocean floor and fragile marine life all trawl particularly bottom trawl to capture large amount of non target species.

g.   DREDGES:- These are shovel-like iron frames with fine net attached. They are used to collect animals living also or attached to the bottom of the sea. Dredges are commonly used in the scallop fishery.

     h.    SCOOP NET OR DIP NET:-

 

2.         HOOK AND LINE:- This gear is probably what is most typically associated with fishing. Hook and lines comes in many different forms that include hand lines, pole, long lines and trolling lines. The hooks are often baited. Long lining or the setting of long lines of baited gear is one of the most widely used forms of hook fishing.

There are two types of longlining

ü  palargic/ surface longlining:- They are set to catch surface swimming fishes  e.g tuna,  herring etc.

ü  demersal/ bottom longlining:-They are set to catch bottom swimming fishes e.g cod, shell fish ,haddock etc.

3.      TRAPS:- Traps are enclosed spaces used to capture fish or invertebrates traps are usually used passively and may be baited to encourage the desirable species to enter. Common examples of traps include pots, fixed traps, bag, net, etc.

            Disadvantages of fishing traps.

            1. The trigger may fail.

            2. Most of the material used are not durable.

            3. It cannot catch large number of fish at a time.

4.      GRAPPLING DEVICES:- These are gear that are usually hand-held and used to target individual fish or mammal. Grappling devices include harpoons, spears and arrows. Grappling gears have little by catch and are used rearly in commercial fisheries.

5.      STRUPFYING DEVICES:- These devices stun fish using explosive or chemical (e.g dynamite, germaline 20, cyanide). These are no commercial fisheries in Nigeria using these capture techniques.

 

 

 

11.3                                         MAINTENANCE OF GEARS

           

Proper care and handling of fishing gears after their use is as important as their use. Proper maintenance increases the durability of the gears.

            Following cares is necessary:

    1. Keep in cool dry place.

     2. Clean (wash, remove debris, weed, mud etc)

     3.Dip the net in dilute KMnO4 or CuSO4 or common salt solution to get rid of harmful bacteria.

     4. Keep away from dilute sunlight.

      5. Mend damage parts.

      6.To increase durability and strength of the fibre of gear,it may be kept immersed for         10-15 minutes in hot tar dilute with kerosene.

      7. Protect wooden parts from termites.

      8. Replace broken or damage part.

      9. Paint or grease metal parts.

   

11.4                              FISHING CRAFTS

  

  Crafts or boat provides platform for fishing operations, carrying the crew and fishing gear.

     It is most essential  for catching the fish in large scale in water bodies. A large variety of craft (boats) have been designed for marine and inland fishing in Nigeria. The types of fishing craft of Nigeria falls under two categories. These are non-mechanized and mechanized fishing crafts.

NON-MECHANIZED BOATS

The categories of fishing craft types comes under non-mechanized are: Dug-out canoe, Wooden/ flat bottom canoe and Dingy.

1.         Dug-out canoes: It is a small-size canoe constructed from large wood logs. These logs are hollow by scooping inner part. There bottom is thicker than sides. Is a simple type of fishing craft for fishing within short distance from the coast. It is commonly used by Ijaws.

2.         Wooden/ Flat bottom canoe- This is an enlarged variety of canoe made of planks on the sides and the bottom is usually flat.

3.         Dingy:- This is a carvel type of boat designed and constructed for a variety of purpose including fishing.

           

MECHANIZED BOATS

Mechanized boats are fishing crafts which are light weight boat powered by a motor. The energy to move the boat comes from an engine fitted to the rear or side, instead of paddlers.

Advantages of motorized boat

1. Fishermen find it convenient for motoring quickly to location.

2. It possible to cover more ground.

3. It also popular for long trips and expeditions where people might get tired of paddling.

 

11.5                             METHOD OF FISH HARVESTING

 

Steps should be taken to prepared a pond for harvesting

1. Stop feeding and fertilizer application a day or two before harvesting.

2. Fish should be harvested during cool weather (early morning or late evening)

3. Harvesting and transportation equipment should be set up well in advance to ensure reduced stress and minimal fish mortality.

            There are two generally harvesting methods of fish.

1. Complete Harvest:- This method involves taken all the fish out of the pond. It is usually done by draining the water from a pond. As the pond water drains the whole pond is seined to reduce the number of fish. The remaining fish are captured by seine and dip nets from a small remaining pool of water called the harvest or catch basin.

2. Partial harvest:- This is done when only portion of the fish are taken out of  pond, at one time.

            Fishing gears used in harvest fish in a pond are gill net, bag net, cast net, drag or seine net, hook and line, trap or basket etc. Other equipments are clean plastic bucket, clean source of water and clean fish storage container.

11.6                                         FISH TRANSPORTING

            Fish like other livestock, are sensitive to changes that occur when they are handled. Transportation stresses fish due to crowding, changing temperature conditions and generally over excitement from handling. Fish may become spined or water quality condition can quickly deteriorate.

            Steps should be taken to prepared fish for hauling.

1. Do not feed fish for at least two to three days before they are transported.

2. It should be hauled at cool water temperature to lower their metabolic rate( 16-18^oC)

3. Haul fish in good quality water.

                                

STRUCTURE QUESTIONS

1.            The following are gears used in harvesting fish except (a) Spear (b) Rake (c) Hook and line (d) Cast nest.

2.            The following are fish craft, except (a) Dingy (b) Dug-out canoe (c )Hand net (d) Trawlers.

3.                            An implement used for catching fish is called (a) dissecting kit (b) fishing gear (c) motor gear (d) water quality kit.

4.            Which of the following gear used in fish cropping? (a) cast nest (b) drag net (c) rake (d) spear.

5.            Separation of smaller fish from bigger ones is called (a) rearing (b) sorting (c) cropping (d) stocking.

 

THEORY

1.            State two fishing crafts used in cropping.

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2(a).       What is a fishing gear?

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 (b)         List three types of fishing gear

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3.      State four ways of maintaining fishing gear

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4.             Name four fishing gear that could be used to harvest fish in a pond.

 

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5.            Outline three steps which should be taken to prepared a pond for harvesting.

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6.            State four ways of maintaining a planked canoe.

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7.      List four types of fishing crafts.

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8.      SPECIMEN D is a NETTING MATERIALS,  E is ROPE and  F is TWINE.

(a) List four items that could be used in addition to specimen D, E and F to construct fishing gear.

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(b)          Name four fishing gear that do  have specimen D, E and F as components.

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(c)           Name four fishing gear that do not have specimen D, E and F as components.

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