CLASSIFICATION OF FISHING GEARS.pdf

CLASSIFICATION OF FISHING GEAR This classification of gear is given by the International Standard Statistical Classification, accepted by FAO. It is define by the structure of the fishing gear and the method of operation. These gears are descri...

CLASSIFICATION OF FISHING GEAR This classification of gear is given by the International Standard Statistical Classification, accepted by FAO. It is define by the structure of the fishing gear and the method of operation. These gears are described fully by von Brandt (1984) and FAO (1975, 1978). 1. SURROUNDING NETS – fish are surrounded not only from the side but also from below, allowing them to be caught over very deep waters. Ex. Purse seines and ring nets 2. SEINE NETS – an area of water is surrounded by the net and by lines. It can be set from the beach, installations, crafts and even rafts. These are usually operated in coastal and shallow waters. Ex. Beach seines, Danish Seines, Scottish Seines 3. TRAWL NETS – operated by dragging or towing the flexible net through the water by fishing craft. It can be further subdivided in terms of depth of operation (surface, midwater, bottom). Ex. Otter Trawl, Baby Trawl, Midwater Trawl 4. DREDGES – these are rigid structures, dredged over the sea bed to separate mollusks, crustaceans from water mud sand and the like. Ex. Hand dredges and Boat Dredges. 5. LIFT NETS – raised during hauling or hauled upward from a submerged horizontal position to catch fish lying above the net by straining water. This class includes scoop nets, lift nets, hoop nets, blanket nets and others which use levers. Ex. Basnig 6. FALLING GEAR – effects capture by covering the fish, pursing the opening and straining the water. The gear is usually operated in the shallow water. Ex. Hand cast nets, cover pots, covering baskets, short cast nets, and lantern nets 7. GILL NETS AND OTHER ENTANGLING GEARS – effects capture by gilling, entangling or enmeshing by a single netting (gill net) or by triple netting (trammel net). Mesh size of a single netting might vary and commercial types might have a length of up to 40 kilometers. Ex. Drift nets, encircling drive in nets and driven in the center by noise and other means 8. TRAPS – passive gears, the fish are guided into collecting chambers from which escape is discouraged by labyrinths and retarding devices such as constrictions and funnels. Ex. Set nets introduced by Japan (otoshi ami), fyke nets, baklad 9. HOOKS AND LINES – fish are enticed by edible or artificial baits or lures to become caught by a hook or spike and held by a line. The fish may also simply snag on a hook passing near by. The hooks may be secured to the line single or multiple in large numbers. Ex. Handlines, pole and lines, jig lines, set long lines, drift long lines and troll lines 10. GRAPPLING and WOUNDING GEAR – used to immobilize and retain the fish by wounding, killing or grappling. Ex. Harpoons, spears, clamps, tongs, rakes, bow and arrow 11. HARVESTING MACHINES – relatively new and are used to transfer fish mechanically from the water. Ex. Use of pumps, hydraulic jets or conveyor belts 12. ALL OTHER FISH CAPTURE GEAR – including hand and landing nets, gathering with hand, with stupefying materials, explosives, and electricity DESCRIPTION OF ALL POSSIBLE FISHING GEARS FOUND IN THE PHILIPPINES (Umali) A. HAND INSTRUMENTS 1. Snares – a running noose at the end of a pole or shaft 2. Miscellaneous – picks, spade, tongs, grabs 3. Spears 4. Harpoons –with pointed barbed blades discharge by a gun or by hand 5. rakes and dredges – non textile webs or splints which effects capture by raking the bottom of rivers and lakes 6. Scoops – lifting instrument made of non textile webs 7. Cover pots – with opening in one end to cover the fish. B. BARRIERS AND TRAPS 1. Barricades – complete barriers principally made of various non-textile materials which prevents the escape of fish from certain natural which they voluntary entered after having been intercepted in their natural course of migration. Movement in their search of food, hiding places or breeding area. 2. Fish corrals – guiding barriers constructed of bamboo, brush, chicken wire which are set in tidal waters or along natural path of migration. 3. Fish Pots – usually baited made of bamboo, rattan, chicken wire in the form of receptacles which prevents the escape of fish. 4. Miscellaneous set traps – crab pots etc 5. Fish Shelters –anchored bunches of twigs, bushes, weeds, piles of poles, etc, which afford refuge for fish. C. LINES 1. Handlines – basically composed of a line and hooks a. Simple hand lines or drop lines – single vertical line carrying either one or two hooks b. Multiple hand lines – a single vertical line consist of several numbers of hooks c. Jigger – lines each bearing a multiple hooked device which is worked by jerking up and down under a bright light. d. Pole and line – it is a simple handline attached to a lope e. Troll lines – long handlines which is usually baited with artificial baits. Operation involves towing of the lines. 2. Longlines – extremely long lines with series of large hooks, it is either set or drifting a. set long lines – anchored in either one or both ends or it cal also be attached to the bottom. It can be set in the surface, obliquely or submerged. b. Drift long lines – long lines without fixed attachments. D. NETS 1. Impounding Nets –capture is effected by confining fish a. Set-impounding 1. filter nets – conical fixed, bag nets with non-return valves and capture is effected by straining water as it is set in flowing water such as river or areas of high tidal fluctuation 2. hoop nets funnel –like nets with non return valves and does not have wings 3. fyke nets – a series of funnel like entrances with wings 4. trap nets – supported by stakes b. Mobile Impounding 1. lift nets – capture is effected by vertical lifting motion a. dip nets - operated by hand b. push nets – triangular in shaped and capture is effected by forward horizontal motion c. skimming nets – large push nets operated by fishing vessels using a skimming motion d. crab lift nets – framed shallow lift nets which are baited e. cover nets – f. cast nets – g. drive-in-nets – operated with a scareline h. lever nets – usually operated with a bamboo raft i. blanket nets – j. bag nets – basnig – conical or cubical bag operated with the aid of light 2. pull or drag nets a. Seines – nets consisting of a bunt or bag, flanked on each side by quarters and wings. 1. drag seines – usually used in the shallow areas (beach seines) 2. reef seines – drag seines used in the reef areas 3. tuck seines – hauling is done on board fishing vessels a. round haul seines – move out in a circle or an arc of a circle b. purse seines – tuck seines having landing piece at one end. It is equipped with a pursing device on the bottom end thereby forming a trap c. ring nets – combination of a round haul seine and a purse seine d. scoop seines – a small purse seine employed as an accessory gear in deep water corrals 4. stop seines – a seine composed of two separate parts, one is used for enclosure while the other one is used in gathering the catch. b. dredge nets and shank nets – bag nets with a raking device c. trawls – net made up of a conical bag with mouth kept open by various devices and the entire gear is towed trailed or trawled usually in the bottom of the sea to capture submerged species 1. Danish – otherwise know as danish trawl with long ropes to keep the mouth open. 2. Irish – with wood or bamboo outriggers to keep the mouth open 3. Japanese – bamboo and wood beams attached to the net 4. Spanish – “paranzella” or “parehas” – two boats are often used 5. Beam Trawls – with wooden beam attached to the tip of the wings 6. Otter trawls – with otter boards attached near the wings 7. V-D trawls – Vigneron-Dahl which otter doors are attached some distance from the wings to effect a larger width for the mouth opening. 2. Entangling Nets – 1. Gill Nets – curtain like nets which the capture of fish is effected by the actual meshes of the net. a. Set gill net – gill nets anchored in one or both ends b. Drift nets – usually fixed in the rear end of the boat allowed drifting c. Encircling gill nets – gill nets are encircled and gilling process is hastened by frightening the fish with various devices 2. Trammel Nets – an entangling net composed of two or more layers. Natural Polymers Cellulose Base Protein Base Regenerated Cellulose Vegetable Base Animal Base Cellulose Derivatives Viscose Acetate Alginate Lanital Cupronium TriAcetate Vicara Fibrolan Ardil Casenka Silkool Caslen Azlon Merinova Wipolan Synthetic Polymers Polycondensed Combination Polymerics Polyadditives Polyester Polyamide Mixed Polyvinyl Polyvinyl Polyacryl Poly Poly  Polymerics alcohol Chloride nitrile ethylene urethane Terylene Nylon Dynel Vinylon PCU Orlon Polythene Perlon U Dacron Perlon Saran Kuralon PeCe Acrilan Courlene Fibre 32 Terital Grilon Vinyon Kannebian Rhovyl PAN Reevon Tergal Kapron Harlon Cremona Thermovyl Dralon Wynene Terlenka Enkalon Verel Mewlon Vinyon-HH Redon Teflon Trevira Amilan Synthofil PeCe-U Courtelle Diolen Lilion Woolon Crylor Lanon Caprolan Dolan Delfion Prelana Steelon Wolcrylon Niplon Rilsan Silon MAJOR CLASSIFICATION OF SYNTHETIC FIBRES IN FISHERIES 1. POLYAMIDE a.Nylon b. Perlon c. Rilsan 2. POLYESTER Terylene (bottom trawl fishery, lamapara nets, lines, lobster pots) Other uses include hauls for lifeboats, hatch covers, sails, and tarpaulins. 3. POLYVINYL CHLORIDE Teviron (purse seines) 4. POLYVINYLIDINE CHLORIDE 5. POLYETHYLENE 6. POLYVINYL ALCOHOL 7. POLYPROPYLELENE 8. OTHERS - Polyurethane, a polyadditive compound is mentioned by some authors as being used in producing fibres. There are also twines made from combination of synthetic compounds, sometimes called as mixed polymerics, and are mainly produced for fishing nets in Japan, this include Livlon, Marlon, Marumoron, Polex, Dynel, Saran, Vinyon, Harlon, and Verel. FISHING EFFICIENCY Observations have proved the improvement of efficiency on gillnets. Nylon and perlon gillnets catch two to seven times number of fish per net per day compares to cotton and hemp (Mugaas, 1959). Catch on cod increased by 4.4 times compared to cotton, coalfish 1.4-2.3 times and mackerel 1.2 -1.3 times (Saetersdal, 1959). Molin (1959) also reported that nylon is superior to cotton, flax, and hemp as much as four times fishing capacity with continuous monofilament and not less than seven times with monofilament. The ratio of catches made with cotton, continuous-multi filament and monofilament is 1:2:14. For set gillnets floating gillnets, trammel nets, and fine herring nets invisibility is important. Strong types of fibres such as polyamide and polyethylene catches more fish than natural fibres such as cotton. The best is undoubtedly the monofilament polyamide. Polyester catching ability and durability seemed to be similar to those of nets made from polyamide fibres. Polyester fibre nets of terylene are used for catching cod and coal fish. High catching ability of nylon can be attributed to low absorption, relatively high elasticity, and high breaking strength. The catching ability of the nets increases with reduced twine diameter (Molin, 1959). However polyamide staple fibres must be avoided in herring and salmon drift nets because this can damage the catch. Twines of polyamide and polyvinyl alcohol are highly recommended. Polyethylene is particularly appropriate for herring drift net. Improvement in set nets are the use of Saran, kuralon, and terylene since it is less sensitive to effects of sunlight. Kuralon cod traps can be used three to six months compare to seven weeks for cotton and hem. Increase in catches has also been observed in trapnets using Polyvinyl chloride (PCU, Rhovyl, and Teviron). Polyamide is good for fyke nets but should not be implored in its leaders. In purse seines, breaking strength must be considered. It is suggested to use PeCe, polyvinyl chloride, polyvinyl alcohol, and polyamide. Efficiency in the gear has been attributed to these materials. It also accepted the use of Marlon made from Nylon/Vinylon as replacement to cotton netting. Dacron is a polyethylene fibre strengthened the hanging and purse lines. Perlon and nylon is recommended for trawl. For trawls, it is 8 to 10 times more efficient and useful than manila trawls. The use of this fibres increased usability of purse seines from 400-500 fishing days with cotton twines to 1300 fishing days with perlon without becoming unusable. It also reduces total weight of fishing equipment and no need for extra expenditures for preservatives, less handling cost, and less number of gears for alternate use. Amilan is used to increase efficiency for trammel, purse seines, and dragnets. It increased towing speed for dragnets due to strength, lightness, small moisture absorption and durability. Menhaden seine, lobster and shrimp gear, tuna seining and tuna longlining is also improving due to the substitution of polyamide. CLASSIFICATION OF FISHING GEARS IN THE PHILIPPINES (Umali) A. According to Materials Used 1. Non Textile 2. textile B. Construction 1. Lines 2. nets C. Mode of Operation 1. Hand Instruments 2. Barriers and Traps 3. handlines 4. long lines 5.impounding nets 6. entangling nets