NOAA Technical Memorandum NMFS 

STRUCTURED FLOTSAM 

AS FISH AGGREGATING DEVICES 

I" h '' 3 Richard S. Shomura and Walter M. Matsumoto 

U 

NOAA-TM-NMFS-SWFC-22 

October 1982 

U.S. DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

Southwest Fisheries Center 
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STRUCTURED FLOTSAM 

AS FISH AGGREGATING DEVICES 

Richard S. Shomura and Walter M. Matsumoto 

National Marine Fisheries Service 

Southwest Fisheries Center 

Honolulu Laboratory 

Honolulu, Hawaii 96812 

October 1982 

U.S. DEPARTMENT OF COMMERCE 

Malcolm Baldrige, Secretary 

National Oceanic and Atmospheric Administration 

John V. Byrne, Administrator 

National Marine Fisheries Service 

William G. Gordon, Assistant Administrator for Fisheries 
ABSTRACT 

A modern adaptation of an old fishing technique is gaining recognition in the Pacific and 

elsewhere as an effective means to increase fishing productivity in the open sea. The use of 

man-made, free floating, and anchored floating 

devices to aggregate pelagic fishes for subsistence, recreational, and commercial fishing has 

increased markedly in recent years; estimates of 

deployed and planned units exceed 1,000. These 

devices have been anchored in depths ranging from 

several hundred to several thousand fathoms. This 

report reviews the development and present use of 

fish aggregating devices in the Pacific and Indian 

Oceans. 

INTRODUCTION 

Possibly the most dramatic change in coastal 

and open-ocean fisheries in recent years in the 

central and western Pacific and Indian Oceans has 

been the use of the fish aggregating device (FAD). 

The development of man-made FAD's has evolved 

naturally from the phenomenon of fish being 

closely associated with drifting objects such as 

logs, algae, and other flotsam (Uda 1933; Kojima 

1960; Hunter and Mitchell 1967; Inoue et al. 1968) 

and stationary objects such as offshore drilling 

platforms (Hastings et al. 1976; Dugas et al. 

1979). The use of FAD's for large-scale 

commercial fishing was first developed in the 

Philippines about 5 years ago (Chikuni 1978). By 

1979 well over 600 FAD's were being used in the 

calm waters of the Sulu Sea and Moro Gulf .l Since 

1979 the utilization of man-made FAD's has spread 

to many island countries in the central and South 

Pacific and Indian Oceans. To date more than 300 

have been deployed. 

The growth in the popularity of FAD's has 

been due to their success in attracting fish in 

large numbers, thereby affecting all levels of 

fishing. The artisanal or subsistence level 

fishermen not only were able to increase their 

catches but were assured of making catches daily, 

commercial fishermen were able to increase their 

catches subst ant ial ly , and recreat iona 1 fishermen 

were able to reduce no-catch trips. The FAD's 

also enabled all motor-driven vessels to reduce 

fuel consumption considerably by eliminating 

unproductive search time. The presence of large 

fish beneath the FAD's enabled handline fishing 

while drifting, thus reducing fuel consumption 

even more. 

Along with the succesaes achieved by FAD 

fishing, there have been some negative developments. The FAD's did not last very long, nearly 

all users experienced substantial FAD losses, and 

conflicts among user groups have developed. 

This report reviews the development of the 

FAD's in the Pacific and Indian Oceans, the 

lMataumoto, W. M. Payao fishing in the Philippines. Manuscr. in prep. Southwest Fish. Cent., 

Natl. Mar. Fish. Serv., NOM, Honolulu, HI 96812. 

results of fishing success, and the problems 

encountered in FAD fishing. 

DEVELOPMENT OF FISH AGGREGATING DEVICES 

The concept of using moored objects to 

attract fish is not new. Fishermen in the 

Philippines used payaos (bamboo rafts 1 prior to 

World War I1 to aggregate fish for handline 

fishing (de Jesus 1982), Japanese fishermen used 

moored bamboo rafts to attract dolphin, Corvphaena 

hippurus (Kojima 19601, Indonesian fishermen used 

anchored fish lures (coconut fronds) to attract 

carangids, mackerels, and clupeoid fishes (Soemarto 19601, and Maltese fishermen used moored 

cork-slabs to attract dolphin and pilotfish (Galea 

1961). Several authors have attempted to explain 

the association of fish with floating objects. 

Gooding and Magnuson (1967) reviewed the hypotheses that have been advanced by others and listed 

the following explanations: (1) food collecting 

around the object attracted fish; (2) negative 

phototaxis in response to shadow cast by the 

object; (3) shelter from predators; and (4) use of 

the object as a spawning substrate. Hunter and 

Mitchell (1967) found little evidence to support 

the mechanisms postulated by others and suggested 

instead that pelagic fishes are attracted to 

drifting materials because the objects function as 

schooling companions, and for species not adapted 

to a pelagic life, the objects may function as 

substitutes for reef or other substrates. 

Initially, FAD's consisted of simple rafts, 

with or without suspended materials, which 

increased the area for organisms to grow on and 

for small fish to seek shelter. The early FAD's 

were anchored in protected waters close to shore, 

but through the years, their use has extended into 

deeper waters and to open-ocean areas requiring 

sturdier construction. In the Philippines, the 

initial simple rafts, which consisted of bundles 

of bamboo , gradually evolved into single- and, 

eventually, double-layered bamboo rafts (de Jesus 

19821, rafts of varied designs, such as the Vshaped raft described by Murdy (19801, and more 

recently to rafts made of steel. The doublelayered bamboo raft, the type most commonly used 

at present, is approximately 2.5 m wide at one 

end, ta ered at the other, and 12 m or more in 

1ength.f These rafts are widely used in the quiet 

waters of Mor0 Gulf and in the Sulu Sea off 

Palawan Island in depths ranging from 2,200 to 

5,400 m. They evolved concurrently with the 

introduction of tuna purse seine fishing in the 

Philippines and with the rapid growth of the 

fishery. They have been extremely effective in 

aggregating fish and up to 200 metric tons (mt) of 

tunas have been caught in a single set of the 

purse seine around the rafts. 

The rough open-ocean conditions in the central Pacific demanded FAD's that were sturdier 

than rafts made of bamboo. Developmental work 

(Matsumoto et al. 1981) at the Southwest Fisheries 

Center, Honolulu Laboratory (HL) resulted in a FAD 

fabricated with two 2084 (55-gal) steel oil drums 

filled with polyurethane foam and held together in 

a frame of angle iron (Figure 1). The FAD's, 

anchored in depths of 400-2,300 m, aggregated 
2 

BATTERY CASE 

-2-55GdL [Rw 

5'CHAlN 

-35 LE9 CHAIN Llhli WEIGHT 

t 

50' CHAIN 

Figure 1.--Fish aggregating device, buoy type. 

fish, mostly skipjack tuna, Katsuwonus Pelamis, in 

sufficient quantities to permit commercial-scale 

fishing by pole-and-line vessels. As a result of 

the success of the HL experiment, the Hawaii 

Department of Land and Natural Resources (DLNR) 

initiated a full-scale FAD system, involving 26 

FAD's made of large tractor tires filled with 

polyurethane foam, for the benefit of commercial 

and recreational fishermen in the State of Hawaii. 

Other Pacific island countries followed suit, 

using the HI, and DLNR FAD's and other types of 

their own design. 

RESULT 

Distribution of fish aanrenatinn devices.-- 

Since 1979, 23 countries have either deployed or 

contemplated the deployment of FAD's within 6 to 

12 months. The localities of deployment are shown 

in'ligure 2. While the FAD's in most countries 

have been deployed to aid the local artisanal 

fisheries, commercial pole-and-line or purse seine 

vessels, have fished around them, particularly in 

Belau, Fiji, Hawaii, Papua New Guinea, and Western 

Samoa. Experimental FAD's installed over the 

Solomon Rise by the Japan Marine Fishery Resource 

Research Center (JAMARC) in November 1980 (Iwasa 

1981) and in the eastern equatorial Pacific by the 

Inter-American Tropical Tuna Commission (IATTC) in 

April-November 19802 have been fished by purse 

seiners. In some countries, such as Western Samoa 

and Fiji, the FAD's have been subjected to fishing 

by both commercial pole-and-line and purse seine 

vessels. 

Tvpes of fish anareaatina devices.--The types 

and number of FAD's used by the various countries 

and the number planned for deployment in the near 

future are summarized in Table 1. As of mid-1982 

more than 379 FAD's have been deployed. Many have 

been lost and many of these have been replaced. 

In addition, more than 147 have been planned for 

fabrication or deployment by mid-1983. 

The types of FAD's used have varied considerably due to the desire and necessity of some 

countries to utilize low cost materials that were 

available locally. The early users (American 

Samoa, Guam, Western Samoa) employed FAD's similar 

to that of the HL experiment. However, their 

FAD's had three instead of two oil drums (also of 

HL design) laid side to side and encased in a 

framework of angle iron. Each FAD had a superstructure supporting a radar reflector and an 

intermittently flashing marine harning light. A 

fish attractant, consisting of fish netting, 

cargo-net appendage made of large (16-1 rope, 

strings of burlap bags and tire sidewalls, was suspended from the FAD to depths of about 20 m. 

The DLNR devised FAD's using old tractor tires 

with diameters of up to 2 m and filled with 

polyurethane foam. Guam and Belau also used 

tractor tire FAD's fashioned after the DLNR model. 

Other types of FAD's included rafts constructed 

from bamboo poles, fiberglass poles, plyboard, and 

pipe frames with steel drum as floats. 

Second generation FAD's consisted of 3-m 

diameter doughnut shaped, fiberglass rings 

(American Samoa), twin- (and later) single-hulled, 

1 x 2 m buoys constructed of 2.5 mm aluminum 

sheeting (Western Samoa), and a cluster of five 

71-cm steel spheres welded together to form a buoy 

approximately 2 m in diameter (DLNR). All FAD's 

were equipped with radar reflector and light above 

and fish attracting appendage below. In some 

cases the latter consisted of 1-2 m plastic 

binding strips attached directly to the anchor 

line or to strands of rope hung from the FAD. 

The FAD user groups differed by locality. In 

most Pacific islands where fishing has been done 

on the artisanal or subsistence level, trolling 

and handline fishing are done from small outboard 

motor-powered crafts. In countries where dieselpowered fishing vessels are used, such as the 

Philippines , United States (Hawaii) , Western 

Samoa, and Belau, or in those countries that have 

entered into fishing agreements with Japanese or 

New Zealand fishing companies in their territorial 

2Guillen, R., and D. A. Bratten. 1981. Anchored raft experiment to aggregate tunas in the 

eastern Pacific Ocean. Inter-Am. Trop. Tuna Comm., 

Internal Rep. No. 14, 10 p. 
3 

~~ 

Figure 2.--Locations where fish aggregating devices have been deployed, 1979-81, 

or where deployment is planned in the Pacific and Indian Oceans. 

waters, such as, Fiji, Belau, and Papua New 

Guinea, fishing on a commercial scale is being 

done either by pole and line, purse seine, or 

both. Recreational or sport fishing is done 

mainly in Hawaii, where fishing is generally done 

by trolling and often with handlines, particularly 

by trailer-boat fishermen. 

Catch.--Regardless of the type of FAD's used, 

the results were the same in all countries. The 

FAD's attracted fish in great numbers leading to 

increased catches. Although accurate catch data 

are not available, owing to reluctance of the 

fishermen to file catch reports, replies to our 

questionnaires from a number of countries disclose 

the effectiveness of the FAD's. In Kiribati skipjack tuna appeared around the FAD's in 9 days and 

catches increased from 100 to 250 kg/day/boat. 

Small (7-10 kg) yellowfin tuna, Thunnus albacares, 

were taken on handlines after 20 days. In the 

Cook Islands evidence of the effect of the FAD's 

was indicated in the lowering of the retail price 

of fish from $3.96/kg to $1.87-$2.20/kg. In 

Western Samoa the average catch of tunas by alias 

(small outboard powered crafts) was 100 kg, with 

individual boats often experiencing catches of up 

to 500 kg in 1 h of fishing at daybreak. From 

prior correspondence (A. L. Philipp, Chief , Fisheries Division, Government of Western Samoa), we 

learned that a commercial purse seiner had made a 

set on an estimated 20 mt of skipjack tuna at one 

of the FAD's. In Fiji catches by purse seiners 

have been as high as 55 mt in a single set around 

the FAD's, and commercial pole-and-line vessels 

have averaged 6 mt/day, compared to 1 mt/day prior 

to the installation of FAD's. In Hawaii the DLNR 

reported that 3,607 FAD visits by commercial and 

recreational fishermen during April 1980-April 

1982 resulted in 400 mt of fish, and averaged 

111 kg/visit. 

The most detailed catch records of fishing 

around FAD's in the Pacific were those obtained 

during the experimental study in Hawaii (Matsumoto 

et al. 1981). In 1978 commercial pole-and-line 

vessels visited the FAD's 247 times and caught 523 

mt (1,153,900 lb) of tunas, with an average of 

2.13 mt (4,690 lb)/visit (Table 2). During the 

months of high catches, 193 mt in April and 196 mt 

in May, individual boat catches of more than 4.5 

mt were made on 23 visits, catches of more than 

9.0 mt on 2 visits, and catches of more than 13.6 

mt on 2 visits. Recreational and commercial 

trolling boats caught an additional 7.3 mt of 

fish. The FAD's attracted tunas of all sizes 

ranging from below 1 kg to over 45 kg. Small 

tunas below 2 kg generally remained in the immediate vicinity of the FAD's, whereas the larger 

skipjack and yellowfin tunas roamed over wider 

areas from 4 to 5 km or more during the day. 

These fish apparently returned to the FAD's at 

night since the day's first catches were invariably made at the FAD's at daybreak and the fishing 

vessels moved away from the FAD's after sunrise, 

while continuously fishing the same school. 

Medium-sized (13-45 kg) yellowfin tuna were caught 

on baited lines either by deep-trolling at reduced 

speed or by handlining while adrift. These fish 

were caught anywhere within 1.6 km of the FAD's. 

Other fish such as marlin and spearfish were 

usually taken by trollers at distances of up to 

2.4 km, whereas dolphin were usually taken well 

within 30 m of the FAD's and up to 8 km away. 

The greatest aggregation of fish yet to be 

seen under a DNLR FAD was a school of large (55-70 

kg) yellowfin tuna (R. E. Brock, University of 

Hawaii, Honolulu, Hawaii, pers. commun.). The 

school, estimated at about 1,600 mt, appeared 

around a FAD that had been deployed for more than 

180 days. 
4 

Table 1.--Deployment and longevity of fish aggregating devices 

in the Pacific and Indian Oceans, 1979-81.1 

Fish aggregating device (days) 

Type of fish No. set No. 

Country or locality aggregating device (planned) lost Range Wean Wax. Continuing2 

American Samoa 

Australia 

Cook Islands 

Eastern Pacific 

Fiji 

French Polynesia 

Guam 

Hawaii 

Kiribati 

Haldive Islands 

Marshall Islands 

Hicrones is 

New Caledonia 

New Zealand 

Niue 

Northern Marianas 

Belau 

Papua Nev Guinea 

Seyche 1 lea 

Sri Lanka 

Tokelau 

Tonga 

Tuvalu 

Vanuatu 

Wallis and Futuna 

Western Samoa 

3-drum 

Doughnut 

3-drum 

Foam block 

3-drum 

Aluminum catamaran 

Plyboard raft 

Bamboo ra'ft 

Wooden raft 

Aluminum catamaran 

3-drum 

3-drum 

Tractor tire 

Tractor tire 

Pentasphere 

Fiberglass-pole raft 

Various types 

Bamboo raft 

-- 

Aluminum single hull 

3-drum 

Tractor tire 

Bamboo raft 

Pipe-frame raft 

-- 

-- 

Aluminum catamaran 

-- 

Plyboard raft 

-- 

3-drum 

Aluminum catamaran 

Totallrange 

11 

5 

4 

2 

1 

4 

5 

120 

2 

1 

8 

3 

5 

26 

34 

3 

9 

20+ 

3 

5 

6 

76 

5 

2 

5 

23 

379+ (147) 

7-510 

14-60 

335-427 -- 

150 

227-592 

62-137 

1 year 

-- 

-- 

-- 

6-123 

28-258 

60-540 

30-450 

7 -40 

-- 

-- 

-- 

-- 

-- 

-- 

150-310 

30-270 

_- 

60 

-- 

-- 

30-210 

-- 

-- 

-- 

236-270 

287-424 

510 

250 

427 

120 

150 

5 92 

137 

-- 

120 

-- 

-- 

123 

338 

540 

450 

40 

-- 

-- 

-- 

-- 

-- 

-- 

210 

270 

-- 

123 

-- 

-- 

210 

-- 

-- 

-- 

270 

566 

40-592 

1Bxc1u8ive of countries that used FAD's prior to 1979. 

2Haximum FAD life continuing as of April 1982. 

3Maximum FAD life continuing as of June 1982. All existing tire type FAD's rwoved and replaced by pentasphere type. 
5 

Table 2.--Fish species caught (in pounds) by pole-and-line fishing in 1978 during the Hawaiian 

fish aggregating device experiment (Matsumoto et al. 1981). 

I 

Species ~ ~~~ 

Skipjack tuna Yellowfin tuna Kavakava Dolphin Totals 

Catch per Catch per Catch per Catch per Catch per 

Buoy Visits Catch visit Catch visit Catch visit Catch visit Catch visit 

A 92 357,044 3.880.3 22.682 246.5 1,479 16.0 a54 9.3 382.031 4,152.5 

B 1 5,110 5,110.0 0 0.0 0 0.0 0 0.0 5.110 5,110.0 

C 14 103,037 7,359.8 1,475 105.4 4,218 301.3 0 0.0 100,730 7,766.4 

D- 139 573,106 4,123.1 80.183 576.9 1,706 - 12.3 3,034 - 22.6 650.029 4.734.0 

Total 246 1,038.297 4,220.7 104,340 424.1 7,403 30.0 3,888 15.8 i,is3,900 4,690.6 

Percent of 

total catch 89.73 9.28 0.64 0.34 99.99 

Svecies of fish caught.--Various species of 

fish aggregate around floating devices. In the 

Hawaiian experiment Matsumoto et al. (1981) 

reported that trolling vessels caught 12 species 

of fish: skipjack tuna; yellowfin tuna; bigeye 

tuna, Thunnus obesus; kawakawa, Euthvnnus affinis; 

dolphin; wahoo, Acanthocvbium solandri; blue 

marlin, Makaira ninricans; striped marlin, 

Tetravturus audax; shortbill spearf ish, g. 

anmmtirostris; rainbow runner, Elagatis bipinnulata; greater amberjack, Seriola dumerili; and 

barracuda, Sphvraena arnentea. Underwater observations disclosed other species normally not taken 

by pole and line or trolling gear. These included 

such species as sea chub, Kvphosus cinerascens, 

scrawled filefish, Alutera scrivtus, rough 

triggerfish, Canthidermis maculatus, mackerel 

scad, Decavterus vinnulatus, pilotfish, Naucrates 

ductor, freckled driftfish, Psenes cvanovhryg, and 

juveniles of many species. Sharks and porpoises 

were frequent visitors around the FAD's. Other 

studies on drifting objects list even greater 

numbers of fish species: Hunter and Mitchell 

(1967) listed 32 species and Gooding and Magnuson 

(1967) listed 35. The kinds of fish found under 

drifting objects depend largely upon the species 

naturally occurring in the vicinity where the 

object is placed and therefore could vary from one 

locality to another. 

1)' 

Imvact of fish aanrenatinn devices.--The 

success of FAD fishing has had obvious impact 

wherever FAD's have been used. In the Cook 

Islands it has led to the construction of a fish 

marketing establishment and, as noted above, has 

resulted in reducing the cost of fish to the 

consumer by nearly 50%. In Western Samoa, the 

increased catches of tunas have led the Western 

Samoans to explore the possibility of exporting 

the excess tuna catches to the canneries in 

American Samoa. In Hawaii, the growth of the 

handline fishery for medium to large (23 to over 

90 kg) yellowfin tuna has resulted in increased 

direct shipments to the west coast and midwestern 

cities of the continental U.S. Other benefits 

also have been realized from FAD fishing. In 

Western Samoa records of a diesel-powered, poleand-line vessel indicated a reduction of fuel 

usage from an average of 443 to 69 $!,/day and an 

increase of tuna catches from 310 to 613 kg/day 

(A. L. Philipp, pers. commun.). 

PROBLEMS ENCOUNTERED 

Despite the successes achieved, FAD fishing 

has not been without its problems. The cost of 

construction and mooring, the relatively short 

lifespan, and the numerous losses suffered have 

all added greatly to the total cost of installing and maintaining the FAD's. To many island 

nations in the Pacific and Indian Oceans, these 

costs have been high relative to the scale of 

their economic resources. 

Longevity.--For the most part FAD life has 

been relatively short, ranging from 6 to 592 days 

(Table 11, and has varied according to the type of 

construction. The FAD's built of fragile material 

or those that were bound with rope, such as plyboard, bamboo, and fiberglass-pole rafts, were 

relatively short lasting. Most of these broke 

apart well within 1 year. The FAD's made of more 

durable material and sturdier construction, such 

as oil drums, tractor tires, and steel spheres and 

aluminum-hull buoys, have lasted the longest (maximum durations of 510-592 days). Some of these, 

the aluminum catamaran types of the Cook Islands 

and Western Samoa with a reported maximum life of 

592 and 566 days, respectively, were still in use 

as of April 1982. The maximum life of the 

tractor-tire type in Hawaii would have exceeded 

540 days had it not been removed intentionally to 

be replaced with the newer pentasphere type. 

%.--The per unit cost of FAD's has varied 

among countries, depending upon the type of FAD 

constructed, the proportion of in-house labor 

contributed, the amount of materials acquired 

without cost, the depth of mooring, and the cost 

of deployment (Table 3). In the replies to our 
6 

Table 3.--Summary of fish aggregating device costs. 

.. 

Cost per fish aggregating device 

Deployment FAD FAD and DeployCountry FAD type depth (m)l only mooring ment Total 

American Samoa 3-drum 

Doughnut 

Australia 3-drum 

Foam block 

900-2,500 $600 $2,400 2Nil 

900-2,500 -- 3 , 000 $ 600 

$2,400 

3,600 

145-183 -- 3,200 1,000 4,200 

145-183 -- 1,400 1,500 2,900 

Cook Islands Aluminum catamaran 1,097-1,463 860 2,770 150 2,920 

Fiji A lumi num cat am a r an NA 860 2,930 ?Nil 2,930 

Box raft NA 27 2,090 2Nil 2,090 

Bamboo raft NA -- 7 80 2Nil 780 

Guam 

Hawaii 

3-drum 550-1,830 -- 2,740 2Nil 2,740 

Tractor tire (A) 550-1,830 -- 2,500 2Nil 2,500 

Tractor tire (B) 550-1,830 -- 3,900 630 4,530 

Tractor tire 

Pentasphere 

228-2,930 -- 2,500 2,000 4,500 

228-2,930 -- 2,500 2,000 4,500 

500 100 600 

Be lau Tract or tire 1,100-3,700 -- 3,340 240 3,580 

1,500 2Nil 1,500 

Tonga Aluminum catamaran 1,097-1,463 860 2,695 25 2,720 

Western Samoa 3-drum 1,480-2,835 600 2,400 2Nil 2,400 

Aluminum catamaran 1,480-2,835 860 2 , 800 200 3,000 

Mean = $2,993 

Kiribati Fiberglass-pole raft 145-183 -- 

Seychelles Pipe-frame raft 900-1,800 -- 

Mean = $2,418 

I__--- ~ _____I_____________- 

kost of average mooring depth. 

2Deployed by government or fishing company vessels at no charge. 

questionnaire the cost of the FAD was generally 

reported together with the cost of the mooring 

system (anchor, anchor line, and other hardware). 

Cost figures of $600 (all cost figures are given 

in U.S. dollars) specifically for FAD construction 

were available only for the three-drum type initially used in American Samoa and Western Samoa-- 

since these units had been constructed under contract in American Samoa--and for the aluminum 

catamaran type ($860) which had been fabricated in 

Western Samoa and purchased by several countries. 

The actual cost of the tractor-tire type was 

difficult to determine since the large items, such 

as tires, anchors, and chain had been acquired at 

no cost or at nominal fees from private firms, 

government supply, or government surplus sources. 

The combined cost of the FAD and mooring 

system provided by the respondents varied considerably from $500-$780 for simple rafts to 

$1,400-$3,340 for the more labor-intensive types, 

depending on the mooring depth, line scope, and 

size of rope used. The average combined cost was 

$2,418/FAD. The mooring system costs for FAD's 

deployed in depths greater than 900 m comprised 

more than two-thirds of the combined costs. Estimates of mooring-system costs alone were $1,800 in 

American Samoa (16-nrm polypropylene rope , average 

mooring depth of 1,417 m) and $1,940 in Western 

Samoa (16-mm polypropylene rope, average depth 

1,930 m), and $1,910 in the Cook Islands (19-mm 

polypropylene rope, average depth 1,259 m) and 

$1,835 in Tonga (19-mm polypropylene rope, average 

depth 1,259 m). A rough estimate of mooring cost 

relative to depth is $50/100 m of line (16-mm 

polypropylene rope) plus $1,000-$1,200 for the 

anchor and hardware, consisting of a 1,000-kg concrete block anchor, 60 m of 13-nrm chain, and galvanized connecting hardware. The cost increases 

proportionately with larger rope, with rope made 

of other synthetic fibers, or with better quality 

swiv e 1 s . 

In addition to these, the cost of deployment 

added significantly to the total cost in some 

countries. Deployment cost varied greatly from 
7 

, 

,- 

I. 

nil to $2,000 each depending upon the size of 

vessel used and the charter rates in each locality. Most countries with no reported deployment 

cost had their FAD's deployed by government-owned 

vessels or, as in the case of Fiji, bamboo rafts 

were fabricated and deployed by foreign fishing 

companies for their own use. The total cost of 

the FAD's, including construction, mooring system, 

and deployment, ranged from $600 to $4,530, and 

averaged $2,993/unit. 

Added to the initial cost were other costs 

such as those incurred in maintaining the deployed 

units and replacing lost FAD's. These costs 

varied by country depending upon vessel charter 

costs, the longevity of the FAD's, and the 

frequency of losses. In some localities, such as 

Guam, Hawaii, and Western Samoa, there were as 

many as two replacements at a FAD site within 2 

year 8. 

Losses of fish anareaatinn devices.--The 

losses of FAD's have been high during the more 

than 3 years they have been in use in the Pacific 

and Indian Oceans. These can be grouped into 

three categories by FAD types: (1) Rafts made of 

bamboo, plyboard, and fiberglass poles; (2) FAD's 

made of steel frame and supports, including the 

oil drum, tractor tire, pentasphere, aluminum 

catamaran, and pipe-frame raft types; and (3) 

FAD's made of foam blocks. In the first category, 

losses have ranged from 63 to loo%, due mostly to 

the disintegration of the rafts. One fiberglasspole raft was reported vandalized and the poles 

stolen. In the second category losses varied from 

40-42.3% for the aluminum catamaran and tractortire types to 73.5-89.2% for the pentasphere and 

oil-drum types. These types were the longest 

lasting with maximum durations of 427-592 days. 

The heavy losses suffered by the oil-drum type 

were in part due to high wind resistance, since 

they contained a large canopy above the waterline. 

It is too early to judge the merits of the foamblock type, since these were installed as recently 

as December 1981. The FAD losses for all types 

were extremely high at 59.1%. 

It is difficult to determine the exact cause 

of FAD losses, since most of the FAD's that had 

broken loose from the moorings have not been 

recovered. The few recoveries to date (20) and 

onsite observations have provided some clues as to 

the probable causes, which are given below. 

Item Known or probable cause Number Percent 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Raft breakage 

Mooring line failure 

Line break by vessels 

Unfavorable mooring site 

Storm 

Vandalism 

Sinking 

Fish bite (shark) 

Inadequate anchor 

Entangled by whale 

96 

35 

7 

6 

4 

3 

2+ 

1 

1 

1 - 

156+ 

61.5 

22.4 

4.5 

3.8 

2 -5 

1.9 

1.3 

0.6 

0.6 

0.6 

In addition to these, 68 losses were of undetermined causes. The losses caused by Item 1 were 

due almost entirely to breakup of bamboo rafts. 

Bamboo poles tied together with cordage apparently were too fragile in open-ocean conditions. 

Losses due to line failure (Item 2) were caused by 

such things as inadequate rope splices, loosened 

shackle pins, and rope breaks caused by twisting 

(insufficient or poor quality swivels). Of these 

the most prevalent cause was attributed to rope 

splice failures. To facilitate the handling of 

the bulky lines which were as much as 2 miles 

long, most users purchased rope in coils of 183 or 

365 m (600 or 1,200 ft). Connecting these coils 

of rope together involved numerous splices, both 

between coils and at rope ends linking up to 

swivels and chain sections. Thus, a mooring at 

1,000 m, consisting of 1,400 m (line scope of 

1:1.4) of rope and a midwarp weight, required as 

many as 10 splices. A midwarp weight to keep the 

excess line from surfacing during changes in tidal 

currents was necessary because of the buoyant 

polypropylene rope. Splicing methods between coil 

sections varied; some were single splices with as 

few as 7 tucks, some with 14 tucks or more, and a 

few with double splices, in which the rope ends 

were overlapped by 2 m or more and each end then 

spliced into the opposing rope. Line failure due 

to loosened shackle was noted in one instance. 

Loss of FAD's due to line breaks caused by vessels 

(Item 3) included such mishaps as the severing of 

the line by the propellers of fishing boats or 

passing ships, where the excess line had floated 

to the surface, and the severing of the lines by a 

tugboat towing cable. The latter incident occurred twice. Unfavorable mooring sites (Ita 4) 

included deployment of FAD's at less than half the 

depth for which the lines had been prepared and 

setting the anchor on top of pinnacles or in 

narrow gorges with steep sides. These resulted in 

the line chafing on the bottom at the midwarp 

weight, submerging of the FAD as the anchor was 

pulled off the pinnacle or line chafing against 

the sides of the gorges. Vandalism (Item 6) consisted of the actual dismantling of a fiberglasspole raft to remove the poles and overloading the 

anchor line by too many boats tying up to the FAD. 

During the experimental phase in Hawaiian waters, 

such incidents as severing the anchor line intentionally by irate fishermen whose fishing line 

(handline) had snagged on the anchor line was 

experienced. Sinking of the FAD (Item 7) occurred 

with the oil-drum type when leaks in the drum 

caused the foam to disintegrate, resulting in the 

loss of buoyancy. 

Considering only those FAD's constructed of 

material more durable than wood or bamboo rafts 

and intended for long-term use, losses resulting 

from mooring line failures, line breaks caused by 

vessel propellers, unsuitable mooring sites, sinking, and inadequate anchor (Items 2, 3, 4, 7, and 

9) account for 85% of the losses. All these 

causes involved human error, and, as such, they 

can be remedied and the losses reduced. Much of 

this can be done by eliminating or reducing the 

size of the high wind-resistant canopy in the oildrum type, using uncorrodable oil drums, treating 

the drums to retard corrosion, replacing heavy and 

massive fish-attracting pendants with pendants 
made of plastic binding strips attached to individually weighted ropes to reduce drag, and being 

especially careful in fabricating the mooring 

lines. In this respect we note that the University of Hawaii Sea Grant Program, the South Pacific Commission, and others have initiated studies 

or are considering engineering evaluations of 

FAD's with the intention of minimizing FAD losses. 

User conflict.--The large aggregations of 

fish collecting around FAD's have attracted a wide 

mixture of fishermen (subsistence level, recreational, recreat iona 1-commercial , and commercial) 

utilizing various fishing gear and methods (such 

as handlines, surface trolling, deep trolling at 

reduced speeds, pole and line with live-bait chumming, and purse seining), and an assortment of 

fishing boats ranging in size from outboardpowered canoes and skiffs to diesel-powered bait 

boats and seiners. This mixture has resulted in 

conflicts among FAD users. Small-boat fishermen 

complain that the larger vessels with large-scale 

fishing capabilities will deplete fish around 

FAD's, and the larger vessel fishermen complain 

that small boats clutter the area and interfere 

with their fishing operations. I n F i j i , conflicts 

have arisen between the two commercial user groups; 

pole-and-line fishermen accuse the purse seiners 

of completely fishing out the FAD's and both 

groups accuse each other of raiding their FAD's. 

Conflicts between large-scale tuna fishermen and small-boat operators can be alleviated to 

some extent by a system of allocating FAD's nearshore to small boats and offshore FAD's to larger 

commercial vessels. Similarly, some method of 

allocation needs to be devised to minimize conf licts between po le-and-line and purse seine 

vessels. 

SUMMARY 

1. The experimental use of FAD's constructed to withstand rough, ocean conditions in 

Hawaii, has led to a tremendous surge in FAD fishing in other areas. To date 20 countries in the 

Pacific and 3 in the Indian Ocean have either deployed or were planning to install FAD's in their 

waters. 

2. The types of FAD's used have varied 

considerably among countries. These included 

FAD's made of oil drums filled with foam and 

encased in a metal frame, large (2-m diameter) 

tractor tires filled with foam, rafts made of 

bamboo poles, fiberglass poles, plyboard, and pipe 

frames with oil drums as floats, 3-m diameter, 

doughnut shaped, fiberglass ring, and completely 

enclosed catamaran and single-hulled buoys made of 

aluminum and filled with foam. 

3. The FAD's have been extremely successful in aggregating fish wherever they have been 

used and have increased fish catches by twofold or 

threefold. This has resulted in a reduction of 

the retail price of fish by nearly 50% in some 

countries and a significant savings in fuel costs. 

4. The per unit cost of the FAD and mooring system ranged from $500 for simple rafts to 

over $3,000 for the more labor-intensive types, 

with two-thirds of the cost attributed to the 

mooring line in FAD's deployed at depths greater 

than 900 m. The total costs were much higher for 

those countries that had to rely upon private 

vessel charters to deploy the FAD's. For these, 

total costs were increased by up to $2,00O/FAD. 

5. Of the 379 FAD's deployed since 1979, 

224 were reported lost, some within 1 week after 

deployment, The longest lasting FAD is still 

operating after 592 days as of April 1982. Mooring line failures, line breaks caused by vessel 

propellers, mooring in unsuitable bottom, sinking, 

and inadequate anchor comprised 85% of the losses 

among FAD's that were intended for long-term use. 

6. The success of the FAD's in attracting 

fish in large quantities has Led to conflicts 

among user groups. These conflicts can be alleviated to some extent by a workable system of allocating FAD usage. 

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