SPC/Fisheries 14/WP.25 2 August 1982 ORIGINAL : ENGLISH SOUTH PACIFIC COMMISSION FOURTEENTH REGIONAL TECHNICAL MEETING ON FISHERIES (.Noumea, New Caledonia, 2-6 August 1982) THE FIJIAN EXPERIENCE IN THE UTILISATION OF FISH AGGREGATION DEVICES by G. Preston Fisheries Division Ministry of Agriculture and Fisheries FIJI ACKNOWLEDGEMENT A large number of people have generously given the benefit of their time and experience,and in many cases private inform­ ation, for the compilation of this report.Some of them are acknowledged in Appendix II,but I would especially like to thank Mr.M.McGregor and Mr.A.Morita for the amount of trouble they have taken to expand on their considerable knowledge of fish aggregation devices. CONTENTS 1) Introduction 1 2) F.A.D. Component Design 2 Anchors 3 Mooring Lines 7 Aggregators 18 3) F.A.D. System Design 31 4) Deployment Considerations 37 5) Evaluation Of A F.A.D. Design 41 6) Production From F.A.D.s 45 Colonisation 45 Purse Seining 46 Pole And Line Fishing 47 Trolling 49 Composition Of The Catch 49 7) Owners And Users 53 Appendices:I Fish Species Reported 55 From Around F.A.D.s. II Information Sources. 57 III Bibliography Of Published 59 Reference Material. Fl.gure_l F&H Ai&t&SATtoN MVK.& AM KAfB MHOAQ> W DfeP UitfeR,A*D[lND (JWitff /I MRiefy Of TDA/A'5 AA/b CTW?A ftSW 5P£C?f5 CaN&kt&A^-e.PlFfEf&NTDFF&ATOfiS FAfoL)£l>iFFSte.NTTyfc£. OF RAFT.So/AF AK.G <,\M<Uk &OMX>L£S oF ZAM6DO.LH&P TO faNZTBXiCT &LiT leP&HA&LG X/VJQ W££Z>/A/£ FH.E&.QENT f&'ACEMfNT. (JiU£A£> A<£ AOlZ Catf-7 STEEL Dfi. ALUAMIOM. S•tf.QcTVfi.eZ UiHicl-l HAME A LDN<Z€& L(F£ Atib CAH 8g FJTTEB idlTH SADAl HtFl£LToA£>. McOLMSTSTfL P»T<r gy6 6pcT g,,-^ 5fee; B ASSIST Lcc^Tlaivl 5TOX.TUAE ffe.A«M FILLC& THfag mAH FlU.fD gfl- J>ftO*13,u)ea»t 6oLTB> ewSPLr ^ AN£H««. J F»A»W puo TTPICAL ^PU>r^gNT. iunFAae FLOAT; Aa$ Ai noom* pomr FOK. PeHi&HA&Le-rype AAFT5. ruis AAAY &e toMtrreo idWertL *kA£: PeflMAH&ir SrRocnXLes hie USED. ^ yzz Y% Y% Y3? SCHOOLS OF F'lSrt tON&Ae&ATE AkoOfib APPENM6B $VtH Ai OLb N£TTM<t OA •VAC fiJfT ANb AeroAN TO /T pfteaDeNn.y, STA\N6S £>P PALM FkDN&& OK USED TYtf«£ E/TH£/l TD FfiPD Oft. To Ufi£ lV>fe A /WfoATfoAiAL , Ai*£ HUHCz FtoDAk THeQAFT. YHe&e £>€A\fg AS A ReFeHeMCe POINT.TYPES. of Fi5K LOMI'CK OCCJJU. \10Me FoK S/M/YL MAA.U4& CXUiANt&M*, \AIKICH At-OCNb FK.H A£&t£&ATiON HC\/\Ct£ 'tHaUls? . FoOM THIS EA6I5 fOK A FeoD CHAM 9t>Q>'<N& Y(rt£.olOF/(<i. S< l?JACK. PAl<iA rgTUWV 4/MAK/XA Wl m coMMenciAUY \/AWA&i£ FiSK species. A WD 5f-YMK6.-mO&e Pkn CAA/ -mew SfCAtttttT mr,?0D\H LAA6.E boATi, oft, SMALL FDOLi'Nfc Skips p/LrfeaeA&.toPe wir gif FLOATING- 1Y« 1b PHeWHT CHAflNH OH SCA &a>. ANCH0H6 Of I-3 70tf6 ARC 0£ev.OFT£H IN THe FOAM DF (£>MCtSTF-FiLie)> OtL bAOMi- CHAiN is us&b AT QMM eHt, OF TH^ ANCHO/1 e.oPe rv tlEDote TH£ nkx. OF LOS^&/ AtAASlDUr\JAHtAU&M OH. TWffT. AT LCAST ID% £>F SLACK UN£ '\£ ALLOUi0>. XvPiCAL AUCHOHiHCr T>ePTH4 B,eiN£- Soo -iOOO PAIWDHfe (2ax> -1>000 FPET} &lM*- INTRODUCTION The use of anchored Fish Aggregation Devices (F.A.D.'s) in the oceanic pelagic-species fisheries of the Pacific is becomming increasingly widespread. The installation of F.A.D.'s is reported from countries as far afield as Malta, Australia, Indonesia, Japan, the Philippines, the Pacific Trust Territories, Hawaii, the U.S. West Coast, French Polynesia, Kiribati, the Solomon Islands, Papua New Guinea and Western Samoa. Despite this wide distribution of F.A.D. technology comparatively little descriptive literature exists on their utilisation, possibly because they have up to now been practical rather than research tools. The F.A.D.'s serve a useful role in reducing searching and chasing time both for the larger industrial tuna vessels and for small commercial or subsistence fishing boats. Despite their value in this respect, F.A.D.'s pose a number of problems in their deployment and utilisation: design factors need to be optimised in terms of construction economy and durability concomi­ tant with requirements of specific fishing methods; F.A.D.'s may increase the vulnerability of different elements of exploited fish populations disproportion­ ately, with possible deleterious effects; and conflicts can and do arise between the different categories of user. These, and the practical difficulties presented by the variety of local conditions prevailing in Pacific nations, must be taken into account in plan­ ning the deployment of F.A.D.'s. Over the past eighteen months insights into some of these problems have been gained during the development of a F.A.D. fishery in Fiji. F.A.D.'s were first deployed here in the second half of 1981 in order to render free-ranging tuna schools available for purse- seining, and their use has since been adopted by indust­ rial pole and line vessels, and in artisannal commercial and subsistence fisheries. This document presents a resume" of current local information and ideas relating to the subject, which will hopefully be of value to other organistions undertaking comparable developments. Many of the suggestions and recommendations contained herein, particularly those relating to F.A.D. design and deployment, are derived from anecdotal information rather than measured and recorded fact, and should be regarded as stages in a continuing process of improve­ ment rather than techniques and practices which cannot themselves be improved upon. In particular readers should note that much of the information contained on component specifications and prices pertains to the Fiji situation at the time of writing (July 1982) only, and this should be taken into account if the information is used in F.A.D. system design. - 2 - A number of references are made in the text to F.A.D. experiences in countries other than Fiji. These are frequently based on personal communications or unpub­ lished documents. For this reason source material is uncited in most cases. A bibliography of published reference material can, however, be found in the final Appendix. F.A.D. COMPONENT DESIGN Tuna fishing vessels frequently find tuna schools close to floating logs and other flotsam. A number of as yet unconfirmed reasons (shelter, presence of food organisms, orientation factor, etc.) have been suggested for this association but the practical value, in terms of rendering schools easier to locate visually (or, if subsurface, by trolling), is clear. Purse seine vessels operating in the Pacific frequently 'label' such flotsam with radio beacons so that they can relocate the log and its likely attendant school of fish. F.A.D.'s are man-made substitutes for naturally occuring floating objects, which appear to be similarly attractive to pelagic schooling fish. In being anchored in known locations they can improve the economics of a given fish­ ing operation by: 1) reducing time and fuel spent in fish searching; 2) improving catch per unit of effort due to increased vulnerability or availability of the target species; 3) improving the value of the catch, in terms of species or size composition. Additionally, F.A.D.'s serve to increase the safety fact­ or in small scale coastal fishing operations (although this is not usually the reason for F.A.D. deployment). The degree of investment involved in placing F.A.D.'S is clearly justified in some cases, but perhaps doubt­ ful in others. In Fiji over 100 F.A.D.'s have been laid by commercial pole and line and purse seine oper­ ators, and, although no comparitive analyses of vessel operating economics have so far been performed, both fleets continue to invest in the activity. (For purse seining F.A.D.'s are essential, since all attempts to set on free-ranging schools have been unsuccessful). Additionally, F.A.D.'s have been deployed by the Govern­ ment Fisheries Division, for the benefit of small scale commercial and subsistence fishermen. Although there are no accurate measures of production from F.A.D.'s by this fishery, it is felt that trials on a larger scale are justified, and the installation of a further 20 in areas accessible to rural fishermen is planned. - 3 - A 'typical' F.A.D., depicted in Figure 1, consists of three major components, which are: 1) Anchor. Usually an unsophisticated arrange­ ment of weights chained together. Features to increase drag resistance, improve ergon- omic efficiency, and reduce snagging potential may variously be incorporated. 2) Mooring_Line. Consisting of chain terminals, rope, shackles, swivels and sinkers. The most costly component, and that which has the greatest bearing on F.A.D. residence time, the mooring line has nevertheless been largely neglected from the point of view of careful design. Apart from simple breakage through overloading, rope twist, swivel fail­ ure, midline sinker tangling, shackle corrosion, splice slippage, knotting and rope abrasion all appear to have variously contributed to raft loss. 3) Aggregator. This may comprise two seperate units, the raft, and an intermediate buoy. Some systems omit the latter feature. Rafts are equipped with appendages to enhance their attractiveness to fish. Presumably because the aggregator is the only component of the installed F.A.D. whose behaviour can be ob­ served, it has been the subject of the great­ est amount of attention by designers, despite the fact that little significant difference either to F.A.D.'s lifetime or to aggregating ability appears to result from design varia­ tions .