,

'q7 e3

10P/TECH/78/21

INDIAN OCEAN PROGRAMME

sma I sca e one-boat purse seiningin 1lankl

UNITED NATIONS DEVELOPMENT PROGRAMME

FOOD AND AGRICULTURE ORGANIZATION

OF THE UNITED NATIONS

Technical Reports No. 21

SCALE (1E-BOAT

IN SRI

by

G. PajotFAO terfiehe

D AD AGRICiI' 'GANXzaPIc. OF

UNITED NATIONS D 0

SE SKENING

1978

UNE ) NATIONS

Indian Ocean Progr IOP/TECH/78 1

RAOT

As Masterfisherman in the FAO DP Fishery elopment Project in Sri(SRL/72/651) the author ho conducted extensive exploratory, experimental and demonstrationfishing with encircling nets for small pelogic species° As a result e purse seinitechnique with light attraction was developed which is suitable for emmorcial application°A number of private fishermen in Sri Lanka have consequently taken this up. Since thistechnology is of interest to many tropical smallscale fisheries with similar fishiconditions, a concise o pilation of the technical reports of the I terfisherman (G. Pajot)is published in the I013 Technical Reports series to enable wider distribution.

This report describes with a minimum of text co lemented by technical drawings andfi es the technique in sufficient detail so that professional fisherman can adopt it°This covers the whole r of craft, deek layout, madhinery, light attraction equipment,two different purse nets for different sise fish td fishing oper tions° Obviously, it0.**ot be gu teed that the method as described in detail will work satisfactorily underall conditions. Modifications and ptations m be required using the report a

technical guide.

INTRODUCTION

2. FISHING BOATS 9 0 000 000 0 0 00000 00 90 90 900090 2

2.1 class of boats eveavoomooGOO9 0 0 0 0 0 0O 00 900 2

2.1 Dedk layouts and accessories 000000009 60 90000 0090 2

. LIGHT BOATS . . 0000400000 0900900 3

3.1 Light skiff for purse semi 00000 900 P000000000 90 3

3.2 Amxiliary light boat 4

3.3 Auxiliary gas 1 p boat 000 09040000 000 O 00000990 4

4, LIGHT FISHING EQUI .15 0o1900.00000e0o000g00(DeOmee 4

4.1 Engine 00 4 000 9 0 OW 90900 9 0000 000000 90 4

4.2 Generators 0 000 0 0 0000000 000()000 e 99000000 5

4.3 Switchboard 900000 00000000000 0 00S 0000 000 5

4.4 Wiring 9 0 00900000000000 0 000 e00 0 00000000 5

4.5 Fishing lamps 0000000009000000000000000909 6

4.6 Bulbs 0000 00 000000 900000900000000000 OD 6

4.7 Batteries . OW 9 900000004000 900090090000 V 6

4.8 Gas fishing lamp 000 90000900000 9 0 0000000 09 0 0 6

ECHO SOUNDER U 0 0000000000000000000000000 0000 7

THE NE T . . 0 000 9 00 0 00 0009 0000000 99009000 7

6.1 Definition of a purse seine 00000 000000000090 90te 7

6.2 Purse seine designs . 90000000000000 90000000 8

603 Net construction 0 . . 000 00 00000 9 90000000 A 0 8

70 LIGHT ATTRACTION TECHNIQUE 090000000 V00000006000000 9

8. FISHING OPERATION eopeooDe006,000pOpeo0o00G00900 9

REFERENCES 00900000090000000090000000900000600

FIGURES 1-20 000 0000000000000000000000000000000 12- 32

Platel Battery box assembly oeallat.O0000000300foom000 33

Plate 2 Beach sounding of a oatch 000 000000 0 090 e VO1 09,00 34

Plate 3 Different phases of the fishing operation ......... 00000 35 - 38

iv-

TABLE OF CONTEWrS

Page

- 1 -

1. INTRODUCTION

I

Small pelagic fish species are oontributing roughly 40 percent of Sri Lanka fish pro-duction. Though there hzt been a small increeee in production over the last decade, it isstill considered that the preseet production could be further increased by approximately.20 to 30 percent, as indicated in Technical Report Ve. 3 "EXploratory Fiehing for Live teitand Commercially Important Small Pelagic Species", of the FAO/UNDP Fishery DeveloerentProject (SRL/72/051) in Sri Lanka.

The main fishing methods so far used for the exploitatioa of the small elare beach seining and gillnetting0

o epecies

The beach seine operation is carried out from rowed dugout or planked cancee (wall )

and is restricted to a very narrow coastal strip approaimately one half mile wide and mainlyalong a eandy coastline with a clear bott

The small'eh gillnet fishery is earried out from traditional craft, such askattumaram and tepeee, which are mostly mechanised and from 17 ft claeu open typo FRP boats,both types powered by outboard engines (6.5 - 15 hp) and sometime by sail. Though the gill-netters fish bsyond the beach seinero ar.e t their operating ranees seldom exceed 7 mi fromthe ahore and their bases.

As discussed in Project Technical Report No oEseell tozh Monofil ent and Multi-filament Experiment with Gillnets", email mesh gillaetting mad contribute to an increaseof production by

introducfee,a elightly lar opon FRP craft (6 s) which could carry more gear.

Secueing the full cemelement of gear for each operating boat.

Partly ueing monofilament netting instead of multifilament on board the PRP openboat.

As part of the proLee.ee of the FAO/UN1P Fishery Developeeee Project (SRL/72/051) inSri Lanka, complying with the Sri Lanka Ministay of noheriee development plan, alternativepossibilities of harvestina email peleec opecioe more aaaeuced rfi methodo wereinvestigated. The resulto of this investiaetion elearly okh,eed that ea:ell-scale one-boatpurse eeining, with or without light attraction, io a highly viable fiehing method forcatching small pelagic species of commercial value and fQT hui maevaption. TheeeT(:e,it was concluded that to substantially increase peo6uceeen, this fiehaean mehodshould be encouraged. This work and findings are diemeeed Peoject Tcohnioal ReportNo. 3.

To some extent, the work of the project included eatenelon cervices to privateentrepreneurs for the introduction of emall-avale puree weiniag. After the first

venturersnerequested assistance, there were problems in obtaining acceptable boato, hauli devices,light equipment, fishing oar, etc. Aiter conoiderable difficulty, two boats could berigged and equipped locally. Their performances have confiemed the previous results andthe viability of this method for harveeting omall pelagic epacies from seen inehorefishing craft. From theee two ventureo it wee clearly evideat that the use of a second-hand boat, engine, light equipment, etc., resulted in such hardship for the owner inensuring a good fishing operation and a rather low eea-going fishing time waa recorded,which upset the overall profitability of each fiuhery. Theeefore it ie coaoidered that,for the introduction of this method, steps ehoula be taken to enable the beet profitabilityof this new fishery.

It was also evident that the extenoion service rendered to the fioheemen by the projecthad not been adequate. If these fiehing methede are mouldered for haevouting thewsresources, extension services should be organized and given to eaivate fiohermen in allaspects of this fishery.

sed on the foregoing, it was felt necessary to produce a technical paper describingin detail the various aspects of this fishing method, boats and accessories, fishingoperations, etc. This report gives ic information on the requiremente for engaging insmall-scale ane-boat purse seining.

2. Flaw BOATS

2.1 Glees of boats

Ekperience has shown that rather small boato can be used for purse seining and thatthe smallest type of boat should have appro i tely ihe following epecifications;

Loa 10mBeam 3mDraft 1.20 mEngine 45 - 60 hpFish hold capacity 7 m3

Boats of these specifications are a stable working platform, with good working deckspace and laze.. enough carrying capacity. For detaile eee Figures 1 and 2.

2.2 Deck la cute and accessories-------__

For single boat purse seining, two dedk layouts have been coneidered (seo Figures 1and 2). In both, the fiehing operation would be similar to the Portuguese e.tho&, ulhiohconsists inshooting and hauling the purse seine over the side, in this instance the star.-board side. This method im certainly one of those most adapted for su-al inshore purseeeining with manual net hauling.

Though it is not illustrated in these two dedk layouts, the combination :,.pect wasconsidered and either of them could be adapted for other fisheries without major modifi-cation.

2.2.1 Wheelhouse

In both layouts, the wh.tlhouses have been offset an the port side. The mainpurpose of this feature in that, on a small boat, this has the particularadvantage of giving better working space on dock for handling the purse eeine,especially when the cabin is mounted astern or midship.

2.2.2 Deck space for the purse seine

In both deck layouts, the purse seine is stacked an the aft-mid-starboardside. This arrangement permita easy handling of the gear and is best suitedfor hauling in the e-ear by hand.

2.2.3 Purse line haulers

A line hauler ira necessary for hauling in the purse line of the seine. Basicallya double horizontal or vertical mechanical capstan is most suitable and such aunit should have the following main featuree:

E), Hauling pull 1 tonb Hauling speed 30 m/min

2

rping head

Various types of capstans are available from foreill.. makers but they are oftenrather expensive and is hard to get forei,e, excs, .. The work done in impro-vising suitable haulers locally been deecribed in Project Technical ReportNo. 5, "Hauling devices for 8.A.1 inshore fishing craft in Sri Lankan,an that report, it is clearly svid t that by using a rear autoobile axle

The optimum size of skiff for this use (row boat) is approximately 3.5 m with a beam

of 1.3 m. This type of sull boat can be constructed with different material, such as

a comparatively cheap but ouitable puree line hauler can be assembled locally.Two different types are shown in Figureo 3 and 4, giving details of theconstruction. The expert would like to indicate that a drum type winch couldbe more convenient but its construction, involving a clutch, band brake, eto,is more complex and expensive.

2.2.4 Purse line drum

Though the purse line can be coiled on the foredeck, it is advisable to have adrum for storing it. It eases the shooting process and eneuree that the purseline will always stay cleared while shooting the gear. The position of thedrum is shown in Figures 1 and 2, its construction shown in Figure 5.

2.2.5 Davit and blocks

For the pursing operation, a davit with biodke leading the purse line to thehauler warping heads is often used. The details of this assembly are shown inFigure 6. In this figure the puree ring bar iw also illustrated.

2.2.6 Purse line roller

As well as tieing the davit mith blocke for pursing the , ar, a side roller canbe used for leding the purse line to the heads of the hauler but this rolleris mainly used with the vertically assembled hauler as shown in Figure 1. Fordetails of this roller assembly, seo Figure 7. Though the purse ring bar isnot illustrated in this drawing, for better handling of the purse rineA it canbe installed and used.

2.2.7 Floatline - Bunt booms

As shown in Figures 1 and 2, eech floatline bunt boom is provided with a smallblock shackled at the far end through which a nylon rope io rigeed with ahook for liftinc the floatline and keeping it away from the side of the boatduring brailing. These booms project about 2 m from the wide of the boat.

2.2.8 Lampehade stand arranment

Sarface lamps are recommended for their cheapnese, efficiency and easineoe tooperate. Different typee of lamp arrangement have been etudied and the multi-bulb shade stand was retained. Two diCferont stand arrangements which provedto be the best waited for a email puree seiner are shown in Figures 8 and 9.They are detailed enough for (7,;-,T uaderetandeng of their construction. The

best location on board is ehown in Figures 1 and 2, it mat also be noted thatan those drawings which show the profile of the lampshade, only one bulb isshown beoause bulbs are in line.

3. LIGHT BOATS

Light attraction was found to be essential for omall-ecale purse ueining. Different

types of light boats have been used and the most suitable are described below.

3.1 Li ht skiff for urse seininE

Whenever the light attraction is to be carried out from the main boat (puree seiner),a small skiff (row boat) is required. This skiff carries aboard equipment providing asource of light (batteries) and lampo for taking over the school of fish from the purseseiner and holding it during the fishing operation.

EngineFuelGenerator outputVoltages

Single p

4.1 Engine

wood planking, plywood and FRP. For illustration ttd details of a light Skiff see Figure 10.The :neral arrangement and dimensions of a V-bottom light boat, locally constructed fromplanked wood or plywood, are given.

This boat is also meant to perform other work, such as beaching or landing the catcheswhen and wherever necessary. See Plate 2.

3.2 L411-.1212:11ALL2nEl

The degree of success of purse seining with the help of light attraction depends verymuch on how many sourcee of light are used. In the case of the local fiehery, at letzt twosources of light should be used at the same time frts different boato. They could either beused from the main boat and a separate auxiliary light boat or from two small auxiliarylight boats.

Besides using the boat for light attraction, during heavy fishing, this type of boatshould be suitable for carrying fish, therefore it ehould have its own propulsion engine,driving the electric generator as well. For illustration and details of an auxiliary lightboat, see Figure 11 which shows the neral arran:tment and givee dimensions of a V-bottomauxiliary light boat, for construction with planked timber, plywood ar FRP.

303 Auxiliary gas 1:td. b

Though gas fishing lets have not en used for oosmercial fishing in these waters, itis anticipated that at least to some extent during certain seasons and Naithin specificareas, this lamp type could be used for attracting smell pelagic species.

For the use of gas as a eource of light, the asrangement of the cs,s fishing lamp an alight boat is illustrated in Figure 12. The dimensions and specifications of the light boatare also given.

To use the same boat for carrying fish, an optional arrangement can be nade for usinan outboard engine as shown in the s e figure.

4. LIGHT FISHING EQUIP

Electric generators are the most common eource of power for light fishing andhave been used nearly exclusively in this area. The generator assembly can bt fixed eitherin the engine room or coupled to an engine and mounted as a portable assembly.

For use in light attraction of small pelagic species on a commercial scale, thenerator must have the following specifications and features:

6 - 8 hpsoline, kerosene, diesel

2 - 3 kW24 - 32 DC

or 110 AC

The generator engine must be powerfUl enough to drive the nerator and, ttsuming that3 kW is the optimum power required, the engine should have a continuous rating of approxi-mately 6 hp.

The use of soline engines has some disadvant

bIFirerisk

Ignition problems due to seawater spray and high humidity

c High running cost when comed to other fuel suchU Short life s

Higher intenance when c ed to diesel type.

1Lower purchasing priceLight weight c red to diesel

1Safety, specially when used in thMinimum maintenance requiredReliabilityLow running

O

5

ngines

One alternative to oline as fuel i§ lekrosenep which is used in combi tion withsoline. The engine ie started with so ine then is switehed over either aut tically

or manually to kerosene. This results in a subst tial reduction of the running cost.

The main advantages of diesel engines are:

The main disadvanto is the high purchasing cost.

z sed on the abovep it is evident that diesel onglnos aro more suitable for driving alight generator, either as a portable unit or fLted in the engine room and, whenever avail-able, should be selected for light fishing.

4.2 Generators

Past light fishing experience has sh that the generating power requirement forattracting small pelagic species on a co ercial scale ice approximately 2 3 kW.

The most commonly used volt for light fishing on a small boat is 24 32 voltsdirect current. This may be due to the higher safety compared to 110 or 220 volts. Inorder to avoid undue power losses, low voltage requires a cable with considerably largercross section Which is more expensive than the thinner cable for higher voltA.le. Theseadditional expenses are often overlooked,

In Sri waters, various volt s ha been led: 32 volts DC9 110 and 220 voltsAC. Therefore, a compromise and considerin3 the oafety, ocetv availability etc., the110 volt AC or DC generator should be considered the moot sulable, For practical reasons,differences in properties of the DC and AC C,TO 1,10t considcroa and are, therefore, notdiscussed,

4.3 Daitchboard

A simple itchboard can be constructed for electric face fishing 1 p by usingregular household electrical equipment. Provision must be made for each lamp to be switchedon and off selectively. A fuse must be inc/uded for each lamp. For higher requirements9 aveltage meter and9 speciallyp adjustable resistors for dimminc the lampe may be included.All components must be of a high enough amperage, depending an the voltage» and power of the1.4», used. The switchboard must be fitted in the boot location, either attached to thegenerator or fitted in the cabin.

Metaile of a simple switchboard for surface fishi s are shown in Figure 13.

4.4 Wiring

The wiring connecting the Inerator to the smitchboard Tnd the owitchboard to each lampmust be of adet..:t.te size according to the current inteneity required. The vireo must be wellinsulated (waterproof) d fairly fle 'ble.

The advent of a oline engine are:

o el or kerosene

10, engine room

The type of bulb ueed so far in thesepowers of from 200 to 1 000 W and volt sattraction bulbs of 110 volts and 500 to 1the small light skiff with surface or suare oon,,idered most suitable.

407 Batteries

6

waters is the regular incandescent one. Differentfrom 24 to 220 have been used. For main light000 7 coneidered most ouktable. For use onreible 1..pL 12 to 24 voLi, and 200 to 500 W bulbs

Assuming that the maximum power requirement it 3 kW, the voltase; used ie 110 V and thecurrent density is 7 A/Mm2, the wiring connecting the generator to the switchboard shouldhave a conductor cross-section of 4 mm2 for each octee(total 8 mm2).

4.5 Fishing lamps

Different lamps are necessary for purse seining with light and theee are discussedbelow.

4.5.1 Mnitibulbs fishing lamp

For light attraction by the ',in boat or an auxiliary light boat, multibulb.shades are considered the beat for the cheapness, practicability, easinees tohandle and fit on board a email boat - Figures 8 and 9 show the profile of amultibulb shade (3-4 bulbs).

4.5.2 Single bulb eurface fiehing lamp

As lamp for taking over the school of fish from the light of the purse se:Werwith the help of a battery set fitted on board the light skiff, a small deephooded eurface lamp is most uitable d coneidered the cheapeob. For illustra-tions of details and installation gee Fi o 10 and 14.

4.5.3 Submersible fishin lamp

A eubmersible fishing l.ip in coneidered suitable as am alternative to the singlebulb surface fishing lamp for use on the light akiff but its canstruction and useis more difficult and oostly (zee Fi lle .0 10 and 15). For a more simple andchear underwater fishing lamp, using a regular incandescent bulb, refer to theFAO Fishing Manual "Fidhing with 1,104,t0 (Ben-Yami, 1976) pageo 55-56. However,in construotioz this type of lamp, a ¡section of a bicycle inner tube can beused as alternative to the rubber hose,

4.6 Bulbs

As a source of light on the email light skiff, oto batteries were -ed almostexclusively for taking the fia,, achool over from the light of the purse ee ner and holdingthem during the ehooting and hauling of the purse seine.

Con idering the short time required for suoh fi ing operatione, the use of batterieswas found to be e.st suitable and is reoce,mded. A battery net colaziete of two 12V 90Ahbatteries conneoted in series so as to obtain 24V, or one 12V, 120Ah battery for powering theaurface or submersible lamp of the light skiff. The rechareeig of the battery set in doneeither with the light generator during the lit attraction operation or off the mnie generatorof the puree seiner. For .:eq more convenient handling, the batteries are put in a woodenbox. This assembly is illustrated in Plate 1.

4.8 Gas fishing lamp

As diecussed before, although 4. :43 fishing lampe have not been used hare, they could bean alternative source of light, at least during oertain seasons in ares uherc fishing

coeeitions are favourable.

For thie purpose, it is assumed that the e lamp Should have A minimum power of 2 000candles. For illustration of this type of lamp and its installation see Figures 12 and 16.

ECHO SUUNDER

Although, in the past, purse seining with and without light attraction 11;4 been donewithout the use of the echo sounder, its application °Ovid improve the catches, preventdamage to the net and thus significantly contribute to the feaeibility of the hole opera-tion.

There io a great variety of equi, ent availabl4 on the international market and it isrecommended that to keep capital investment down, purchase of unnecessarily sophisticatedunite be avoided. A small and relatively inexpensive recording echo counder with thefollowing operational characteristic:1; ehoule be quite sufficient:

Maximum depth not exceeding 200 300 mOutput power not exceeding 15 20 WWhite line not necessaryRecording paper width 10 15 cmDesirable characteristics: Variable paper speed;

good scale expaeleion5spray reactance;flaeher indication for paper saving;local eervioe available.

Many hints for the operation of the echo sounder in purse seining with lieet attraction aregiven in Chapter 6, pages 68-709 and 81-84 in the FAO Fiehing Manual "'Fishing with Ligwo

THE NET

The definition, construction and operation of the purse seine are dieoussed in thefollowing eection.

6.1 Definition of a pease Oeine

A puree seine is a long wall of netting7 hanging° down between float,and leadline withan essential feature, whioh io pureing the net by pulling a drawline (purse line) which isthreaded through a series of rings rigged along and below the leadline, so that the leadlineis bunched and hauled up to the eurface, closing the bottom of the net and impounding thecatch before hauling the net aboard.

A purse seine is made by assembling different parts of the gear having specific mesh,twine sizes, etc., and by definition referred to as follows:

Main components:

1 Body2 Bunt3 Selvedges4 Wing or breast5 Framing lines (floatline, leadline and gavels (breastlines)6 Bridles7 Purse rings8) Purse line

For illustration see Figure 17.

6.2 Purse seine designs

Designs of purse seines are presented in Figure 18 for small pelagic species likesardine, soad, mackerel, etc., and in Figure 19 for the same small pelagic species but whereother species like anchovy prevail, The designs resulted from the work carried out in thesewaters using small inshore fishing boats which has been reported on previously in ProjectTechnical Report No. 3 "aploratory fishing for live bait and commercially important smallpelagic species". Based on this work, it was clearly evident that, for catching smallpelagic species with or wtthout the help of light, the optimum specification range of thegear should approximately be as follows. For detailed specifioations of two purse somos,see Figures 19 and 20.

Purse seine specifications

Hung length 200 250 mDepth stretched 30 36 mHanging ratio 0080 0,85Netting: knotless and knotted

Twine sizes (R tex)

Body 75 - 125Bunt 125 200Selvedges 250 380Wing 375 - 500

Mesh sizee (stretched mesh mm)

Body 12 20

Bunt 10 16

Selvedges 18 30Wing 30

Ropes

Floatline PA 0 10 12 mmLeadline PA 0 10 12 mmTowline PA 0 10 12 mmPuree line PA 0 14 16 mm(braided)

Floats plasticSinkers leadPurse ring brass or galvanized iron

In the designs, the abbreviations and symbols used may not be familiar to all localfishermen. Therefore, to assist in reading the drawi.v an explanatory table was prepared(seo Figure 20).

6.3 Net construction

A purse seine is made by assembling the different sections with their specific mesh,twine sizes, etc., into one body of netting. This is done by lacing the different sheetsof netting along their depths to each other by evenly taking up the extra meshes in thedeeper sheets. The tapered bunt is laced to one end of the body by evenly taking up theextra meshes of the bunt, which results in an additional taper,. duo te the smaller meshsize in the bunt.

As for the bunt, the cut tapered ming is also hung to the other end of the body bytaking up the extra meshes in the same legy,

9The selvedges are also laced to the body and bunt while taking up the extra meshes in

the latter parts. Finally, the netting wedges for reinforcement of the lower selvedge arelaced to the latter according to the position of the purse ring bridles. Fbr details seeFigures 18 and 19. Thus, the assembling of the netting is completed and it is ready forhanging to the framing lines. All ropes have to be prestretched and the floats or leadsstrung on. At the bag end more floats per rope length unit are required. The hangingof the selvedge strips to the framing lines can be done in different ways and two alternar.tives are proposed (see Figure 19). In alternative A, a 2-3 mm diameter cord(hanging twine) is reeved through the first mesh of the selvedges, then the same rope islashed to the floatline, making sure that the desired hanging ratio is according to thedesign. For detailed illustration eee Figures 18 and 19. In alternative B, the hangingtwine is first seized to the stretched framing lines strung with floats or leads forming aseries of arcs created by knotting the hanging twine to the framing line at regular intervals.The knot used is illustrated in Figures 18 and 19. Then the netting is hung to thehanging twine, taking great care that the hanging ratio ie as indicated in the design.

The purse ring bridles are fastened to the leadline at reinforcement points of the selvedgeand are evenly distributed as per the design, The knot used for attaching the purse ringto the bridle is shown in Figures 18 and 19.

The purse line is made out of synthetic fibre, preferably of braided polyamide (PA).The other essential accessories are gavels and buntline with a large float. For details seeFigures 18-19.

Then the gear is completed and ready for fishing.

LIGHT ATTRACTION TECHNIOVE

The light attraction technique begins with selection of the best fishing ground, eitherat random or even better with the help of an echo sounder/fish finder, for identification ofthe fishing depth, the nature of bottom if necessary and the location of any traces of;schools or layers of scattered small fish.

After the location of the best fishing grounds, the light boats and the purse seinerare anchored at different stations at a distanoe of at least 500 metres, Then the lights

are switched an, generally for 2 to 4 hours, a period which is sufficient for attractingsmall pelagic species when present. As the light attraction process is going on, theaggregation of fish should be observed approximately every 30 minutes either by eye orbetter by using a fish finder. The final decision to set the purse seine will depend on thevisual observation and/or recording and, regardless of the time, if the school of fish foundis sufficient, the masterfisherman will deoide to set the purse seine. Prior to setting,the main light attraction power will gradually be reduced by switching off one lamp at atime, then finally the fish will be transferred to the light skiff by simultaneouslyswitching off the last lamps of the main light attraction and switching on the small lamp ofthe light skiff. The purse seiner then starts the fishing operation.

FISHING OPERATION

The fishing operation consists of surrounding or encircling sighted schools or aggrega-tions of fish attracted to the light. This operation results in the formation of a roughcircle, often egg shaped. First the buntend of the net and the purse line are fastened to

the buoy. Then the purse seiner moves in a:circle, paying out the net, to reach back to the

buoy attached to the first end of the net set. Once the encircling is completed, the purse

lino is drawn with the help of a double capstan or other type of line hauler, On completion

of the pursing operation, the leadline is bunched on the surface, closing the net and pre-

venting the fish from escaping. Then the net is hauled on board, starting from the wing end

so as to gradually drive the fish into the bunt, of which the floatline has already beenlifted and kept away from the side of the boat with the help of the booms and thereby pre-venting fish jumping out of the net and facilitating the brailing of the oatches. The

brailing of the catoh is done with large scoopnets, often hand operated, or with a brailer

10

rigged to a cargo boom.

The purse seine is retrieved in the reverse order of setting and by this procedure, atthe end of the haul, the net is ready for the next fishing operation. For illustrations ofthe fishing operation see Plate No. 3.

11

REFERENCES

BenYami, M., Fishing with Light. FAO Fishing ual, London, Fishing News (Bool,cs) Ltd.1976 121 p.

Technical Report No. 1, FAO/GIMP Fishery Development Project, SRL/72/051. Small MeshMonofilament and Multifilament Ekperiment with Gillnets.

Technical Report No, 3, FAO/tNDP Fishery Development Project, SRL/72/051. EbcploratoryFishing for Live Bait and Commercially Important Small Pelagic Species,

Technical Report No, 51 FAO/UNDP Fishery Development Project, SRL/72/051. Hauling Devicesfor Small Inshore Fishing Craft.

FISH HOLD CAPACITY 7m2

DECK

UNDER DECK

t\V- GRATTING

ENGINE

DIESELTANK

12

Figure 1

GENERAL ARRANGEMENT FOR INSHORE PURSE SEINER

PARTICULARS WITH ENGINE- WHEEL HOUSE ASTERN - MID SHIP

PROFILE 11111110

MULTI- BULBSSTAND

PURSE LINEHAULER

WHEEL HOUSE TOP

PURSE LINE - ANCHOR LINEDRUM

STEM ROLLER

PURSE LINEANCHOR LINE

DRUM

5m.

LOA 9-90m.LWL 9.00m.DECK BEAM 3-25m.

WL BEAM 2.95m,DRAFT 1-50 m.

ENGINE 45 - 50 HP

Figure 2

PARTICULARS

LOA 9.90m.LW L 9.00m.DECK BEAM 3.25 m.

WL BEAM 295m.DRAFT 1.50 m.ENGINE 45 - 50 HP

FISH HOLD CAPACITY -7 m2

GENERAL ARRANGEMENT FOR INSHORE PUSE SEINER

WITH ENGINE- WHEEL HOUSE FORWARD

UMWEn4k

PROFILE

DECK

MULTI- BULBS STAND

UNDER DECK

NET GRATTING

F W

TANK

RUDDERo STORE

COMPARTMENT

F W

TANK

FISH

HOLD

MAST - BOOM

PURSE RINGSBAR

- 13 -

PURSE LINEHAULER

BATTERY

TOOLS

PURSE LINEHAULER

DIESELTANK

ENGINE

DIESEL

TANK

WHIP ANTENNA

LIFE RAFT

QUARTER

CREW

QuARTER

WHEEL HOUSE TOP

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14

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C x 2 24 cm,co'C I 6 cm. (2(Cx 2 8 cm. Qi

V PULLEYS REDUCTIONRATIO FOR THE HAULER:I : 3

V PULLEYS REDLCTIONRATIO FOR THE GENERATOR: 4 :1

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ALT

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Pir-,-Are 20

ABBREVIATIONS AND SYMBOLS USED FOR PURSE SEINE DESIGNS

All bor

Alternative

Brass

Hanging ratio: Ratio between the length of' a given portion of mounting rope and the

iongth of the stretched netting hung on the portion of ropo.0.90 E080 Er.0. 7 EL*0.: E=0.40

AB

ALT

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( R 25 ten % I ply )

ST Steel

0 Diameter

Thickness

Plate 1. ttery box assembly

- 34 -

Plato 2. aoh I ding of a catch

-35-

Plate 3. Different es of the fishing operation

an'

Plate 3 (cont.). Differ t phases of the fishing operati

36

- 37 -

Plate 3 (cont.). Differ t ph es of the fishing operati

,

t,

vL44

38

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plate 3 (contde ), rnt pl 9 of the fishing o ati

- 39 -

TECHNICAL REPORTS OF THE INDIAN OCEAN PROGRAME

Iran - Formation of a Fisheries Development Branch within the ADD'. Lam, A.,TOP/TECH/75/1.

Pecherie de Crevettes - Rapport au Gouvernement de la Republique Malgache. Labon, A.,TOP/TECH/75/2 (not publidhed).

FiSheries Development Pousibilities in the Republio of Kenya. Lebo% A., IOP/TECH/75/3,

4, A Report on the Building-up of a Statistical System for the Collection of MarineFieheries Statistios in the United Arab Emirates, Banerji, S.K., IOP/TECH/75/4.

5. Report to the Ministry of Agriculture and Fisheries - United Arab Emirates. Labon, A.,TOP/TECH/75/5.

6, Some Developments in the Tuna Fisheriee in the Indian Ocean. Kearney, R.E.,TUP/TECH/75/6.

Statistical System of Marine Fisheries in Mauritius. Banerji, S.K., TOP/TECH/76/7.

Establishment of an Agricultural and Fisheriea Development Authority in the UnitedArab Emirates. Gustafeson, N. and G.K.F. Moore, IOP/TECH/76/8.

United Arab Emirates - Programme of Development of Fiehery Harbours ama LandingPlaces Reconnaissance Survey Report. Gunkian, W., TOP/TECH/76/9.

10, Fishery Statistical System in Sri Lanka. Banerji, S.K., IOP/TECH/76/10 (restricted).

Summary Report on Cruise of the R/V SHOYO MARU in the North Arabian Sea. Yamanaka, H.,Y. Nishi wa, J. Morita, (translated and edited by S. Hayasi, Indian Ocean Programme),TOP/TECH 76/11 (restricted).

The Sultanate of Oman Five-Year Fieheries Development Plan, Labon, A., TOP/TECH/77/12(not published).

Fisheries and Marketin& in the Yemen Arab Republic, Campleman, G., V. Perovic andB. Simone, 10P/TECH/77/13.

Summary Report on Cruise of the R/V SHOYO MARU in the North Arabian Sea, Yamanaka, H.,M. Yukinawa and I. Nakamura, (translated and edited by S. Hayaei, Tokoku RegionalFisheries Research Laboratory), TOP/TECH/78/14,

Report of the Joint Miesion to Plan Development of the Sardinella Fisheries in theBali Strait, TOP/TECH/78/15.

Markets for Fish Meal in the Near East Region, Naylor, J., TOP/TECH/78/16.

Development of Fisheries in the Exclusive Economio Zone of Sri Lanka. Campleman, G.,TOP/TECH/78/17 (restricted).

Implications of the Extended Zones of Maritime Jurisdiction for the Fishing Industryof Thailand. Labon, A., J. Carros and J. Gulland, TOP/TE0H/78/18 (restricted).

19. Report of a ssion to &amine the Implications of the New Oceva Regime for FisheriesDevelo ent in Somalia. Silva, Paynes, j.J. Rambeaa mid a.P.K. Moores10P/TEC1/78/19 (restricted).

20. el ent of Fisheries in the Ekclusive ECM. Savini. 10P/TEC1/78/20 (restricted).

t. z no of the Seychelles. 4 e R.L

210 Smallscale Oneboat Puras Seining in Sri Lanka, "0 GO IOP/T /78/21.

W/L9496(E/4.79/1/160