A Night Handline Fishery forTunas in Hawaii

HEENY S. H. YUEN

Introduction

Modern commercial fishing fortunas brings to mind large superseinersand longliners with complicated andcostly equipment and gear. In contrast,the rapidly growing night handlinefishery for tunas near the island ofHawaii is remarkable in its simplicityand effectiveness. This fishery catchesbigeye tuna, Thunnus obesus; yellow­fin tuna, T. albacares; and albacore,T. alalunga; on elementary gear, ahook and line.

The effectiveness of the method isdemonstrated by its catch rate which isapproximately two fish per hook pernight on the average. In comparison,catch rates of Hawaiian longlinevessels are on the order of 0.03 fish perhook per day (Otsu, 1954).

Because of its inexpensive require­ments, this method of fishing seemslike a promising method for the manyfinancially impoverished island com­munities in the tropical Pacific Oceanto utilize a marketable resource ofexport value. Nevertheless nighthandline fishing for tunas is not awidespread practice.

ABSTRACT-Night handline fishingeffectively catches tunas in localizedareas. The fishery for tunas by thismethod in Hila, Hawaii, experienced arapid growth when high prices on thefresh tuna market and fast air delivery todistant cities made new markets for thecatch available. The simplicity of themethod and low cost ofequipment makesit a promising methodfor island culturesof low technology to usefor developing afishery. The paper describes the fishingmethod and gear in detail.

August 1979

To my knowledge, the only otherplace where this method is used is in thePhilippine Islands. There, virtually allof the commercial yellowfin tuna catchis made on night handlines (OswaW).Even in Hawaii this technique is usedonly by fishermen on the island ofHawaii. Fishermen from the otherislands in the State have not yetadopted it. The information in thispaper may stimulate interest in hand­line fishing in other areas.

This report includes a brief history ofthe fishery in Hawaii, a description ofthe fishing method and gear, a descrip­tion of the catch and its value, and asummary discussion. The data for thisreport were gathered in 1976. Minorchanges in method and new fishingareas since then are incorporated inthis report.

History

In 1976 night handline operationsfor tuna in Hawaii were made exclu­sively from Hilo (population 28,500).The following account of the origins ofthe fishery are from interviews ofoldtimers in the fishing community ofthat city as written references were notfound.

Immigrants from Okinawa arebelieved to have started the fishery.They went out at night to catch squidas they had done in Okinawa. Occa­sionally something large would strikeand snap their lines. Upon checkingwith the native Hawaiians they learnedthat the strikes were probably made bylarge tuna. They subsequently equip-

'E. Oswald, South China Sea Fisheries De­velopment and Coordinating Programme,Makati, Rizal, Philippines. Pers. commun.,1976.

Heeny S. H. Yuen is with the HonoluluLaboratory, Southwest Fisheries Center,

ational Marine Fisheries Service, NOAA,Honolulu, HI 96812.

ped themselves with gear to catch thetuna.

The exact year when the fisherystarted is not known. The first Oki­nawans arrived in Hawaii in 1899 towork in the then burgeoning sugarindustry (United Japanese Society ofHawaii, 1971). It took another 7 or 8years, however, for the immigrants toreach large numbers. By 1911, 12,000were living in Hawaii. Allowing fortime to fulfill their contracts with thesugar plantations, I would guess thatthe fishery for squid started in thesecond decade of the 1900's.

In the early years of the fishery theboats were powered by sail; by the1930's up to about 40 motorized boatswere involved. Until World War II thefishery was primarily for squid. Theincidental tunas caught were known as"ika-sibi" (squid-tuna in Japanese), thename by which the fishery is calledtoday. Because the boats were toosmall to have the large fish on boardand did 110t carry ice to chill the catch,these tunas were towed alongside theboat on the way to port. Consequently,the ika-sibi had a reputation for havingpoor quality and could not compete onthe market with tunas caught onlonglines.

The squid fishery stopped abruptlyon 7 December 1941, with the Japaneseattack on Pearl Harbor. Maritimerestrictions prevented boats fromfishing at night for the duration ofWorld War II.

When the fishery was resumed afterthe war, three to four boats equippedwith iceboxes targeted on the tunas.Until 1971 the tuna-oriented part of thefishery was limited to these few boatsby the market for fresh tuna. The entirecatch was sold on the island of Hawaii,which had a popultion of 55,000­63,000 during that period. By 1971fresh tuna prices had increased enoughto make air shipment of tunas to othermarkets economical. By 1976 the nighthandline fishing fleet had grown toabout 30 boats, about half of which

7

Figure I.-Fishing locations of night handline fishery for tunas.

li6° W

were part-timers. In 1977 over 40 boatswere involved in the fishery from Hiloand about 10 or so boats were fishingfrom Kona on the west side of theisland.

. Fishing Operations

In 1976 the only fishing area waslocated 24-32 km (15-20 miles) north­east of the port city of Hilo on the eastside of the island. Since then the fisheryhas expanded to other areas, the mainones of which are east of Hilo, southof Pohoiki, and the southern half ofthe west side of the island (Fig. I). Theareas fished are characterized by amarked increase in slope of the bottombeyond the edge of the shelf that ajoinsthe island. The depth of the shelf at theedge is about 400 m in the areas on theeast side of the island and 200 m on thewest side. During 1978 a few fishermenfrom Kona, a district on the western

8

,-------20

I 5°

side, successfully used night handlinesin areas where the bottom is 4-5 kmdeep and relatively flat. They fished atnight at sites where tuna were locatedduring the day (Morioka\

Geographic expansion of the fisherywas accompanied by an expansion inthe fishing season. In 1976 the handlinefishing season was from July throughDecember. This still holds true for theeast side of the island. On the west sideof the island the season runs fromJanuary to April.

The boats leave port to get to thegrounds at sundown. Upon arrival theengine is turned off and a parachute isattached to the bow and lowered intothe water as a sea anchor. Two abovesurface lights and one underwater light

2R. Morioka, Hawaiian Telephone Company.P.O. Box 1510, Kailua-Kona. Hawaii 96740.Pel's. commun., 1978.

are turned on. Some fishermen use justthe above surface lights and some usejust the underwater light but most ofthem use both types. Typically 25-Wand 50-W incandescent bulbs are usedfor the above surface and underwaterlights, respectively. Some fishermenuse slightly brighter lights on moonlitnights.

The first fishing operation is to catchthe squid, NOlodarus hawaiiensis, forbait. Cross-sections of mackerel scad.Decaplerus pinnulalus, or frozensquid, Loligo opalescens, roughly Iinch (3 cm) wide, are used as chum.Squid are caught by angling andgaffing. The hooks are baited withmackerel scad by cutting off the tail sothat the body of the scad is the properlength to fit on the shank of the hookand inserting the shank of the hookthrough the length of the fish startingwith the cut end and ending at themouth. A light line or wire attached tothe proximal tip of the shank is woundaround the fish to keep it from fallingapart. This makes it possible to use thesame piece of bait repeatedly despitethe squid bites that are inflicted upon it.The baited hook is tossed out about 5m and slowly pulled back to the boat.In this manner the hook is used notonly to hook squid but also to lure theschool of squid to within gaffing rangeof the boat.

A few fishermen prefer to gaff thesquid exclusively. In this case the squidare lured to the boat by tossing out awhole scad hooked through the headwith a fish hook and retrieving it in thesame manner applied to the squidhook.

In the past, fishing for tuna beganafter 5-10 squid had been caught.Today most fishermen bait their tunalines with mackerel scad and proceedwith fishing while catching squid forbait. In fishing for tuna the baited hookis lowered to 20-30 m. The fishing lineis tied to the boat with a restraining lineto keep the hook at the desired depth.The restraining line is fairly heavy,about 18-34 kg (40-75 pounds) break­ing strength, because it is intended toset the hook when the fish strikes.Three well separated hooks are fished:One at the bow, one amidship, and oneat the stern. Some boats fish a hook at

Murine Fisheries Review

Figure 3.-A squid gaff.

I~

-

Figure 2.-Drawing ofa hook forcatching squid.

Above surface lights are 25-W incan­descent bulbs with polished metalreflectors. Usually two of these areused. The underwater light, usuallyone, is a 50-W incandescent bulb thathas been waterproofed and weighted.Brighter bulbs are sometimes used formoonlit nights. The lights are poweredby storage batteries. The baseball batand wooden mallet are used forstunning fish.

A wide assortment of boats is used inthe fishery. These range from 6-m (20­foot) fiberglass skiffs to an 18-m (60­foot) boat that fishes longlines duringthe off-season. The boats are usuallymanned by two men, but fishermenwill often go out alone.

---

JReference to trade names or commercial firmsdoes not imply endorsement by the ationalMarine Fisheries Service, NOAA.

squid. A typical squid jig (Fig. 2) hasa shank 25 cm long and eight prongseach of which is 5 cm long. Variationin the jigs occur in the number ofprongs, which may be 6-10, and in thelinear dimensions, which vary about10 percent. The gaff (Fig. 3) is similarto the jig but with slightly longerprongs (7 cm). The handle is astraight piece of bamboo I m longand 2 cm in diameter at the largerend.

The tuna fishing gear (Fig. 4)consists of a hook, a leader, a leadweight, and a line. The hook (Fig. 5)is of a Japanese design (Tonkichi 3

BKM #54). The leader is either seven­strand stainless, 227-kg (500-pound)test, wire or monofilament nylon ofsimilar strength, sometimes braided foreasier gripping. The leader lengthpreferred by most is about I m butleaders 0.6-1. m are used. The weight(Fig. 5) is a lead tube of 227-397 g (8-14ounces). The tube is bent at the middleabout 30° to keep it from rollingaround on the boat. A stainless steelrod is placed through the tu be and itsends are fashioned into eyes to facili­tate the attachment of line and leader.The favorite material for the lines ispolypropylene rope either 0.95 cm (Ysinch) or 0.79 cm (5/16 inch) indiameter. Lengths of the line rangefrom 110 to 130 m. The fishing gear iscoiled and kept in a square woodenbox for easy handling.

Other equipment used by all boatsare a parachute, lights, and a baseballbat or a wooden mallet. The parachuteis 7.2 m in diameter and equipmentsurplused by the military. The lights,used for attracting squid, are of twotypes: Above surface and underwater.

each corner of the stern and oneamidship. one of the boats seems tofish more than three hooks at a time.While waiting for the tuna to strike, thefisher:nen continue to fish for squid.

On the western grounds where squidare scarce, squid fishing is often notdone. The tuna hooks are baited withmackerel scad.

When a tuna strikes, the restrainingline sets the hook and the fish isallowed to run until the outgoing line isslow enough to be handled. The fish ishauled by hand to the boat. At thispoint the fishermen differ in theirtechniques; some stun the fish and thengaff it; others stun the fish after it is onboard. Fish are stunned with a blow onthe head with a baseball bat or awooden mallet. Recently many fisher­men have resorted to killing the fish byshooting it in the head with a handgunwhen it is alongside the boat.

When there is a strike at least one ofthe other two lines is removed from thewater as soon as possible to reduce thepossibility of the lines tangling. Thispractice is not followed when the tunais small enough to land quickly orduring times when strikes are infre­quent. Tuna strikes tend to be clusteredand while it is possible to keep two lineswith struggling fish from tangling, it isalmost impossible to do so with threelines. The fishermen claim that tunaschools move away when the lines gettangled.

The fish are stored in iceboxes with amixture of ice and seawater. Wheneverthe catch exceed the icebox capacity,excess fish are left on deck, coveredwith wet canvas or burlap, and cooledperiodically with seawater. Departurefrom the fishing grounds is timed sothat the fish can be delivered in time forthe 7:00 a.m. auction. The newer andfaster boats can thus stay on the fishinggrounds longer.

GearTwo sets of gear are used, one for

catching squid and the other forcatching tuna. There is much indi­vidual variation in the choice ofmaterials and design of the gear. Thefollowing description is of the mosttypical gear.

Jigs and gaffs are used to catch

August /979 9

CatchData on the catch, i.e., species, date

of capture, number of fish, weight ofeach fish, and ex-vessel price for theyears 1973-75 inclusive, were madeavailable by Suisan Company, Ltd.,which handled the sales of virtually allthe catch of the night handline fisheryat that time. On the sales records,weight is expressed in whole pounds. Inthe data analyses the pound wasretained as the unit of weight. In thefollowing presentation where weight isgiven to 0.1 kg, it is simply the metricequivalent of the original expression inpounds and was not meant to conveyany implied precision.

The weight and value of the totalcatch are tabulated by species and yearin Table I. The annual weights andvalues for all tunas com bined show aconsistent growth of the fishery from89,000 kg (196,000 pounds) to 155,000kg (341,000 pounds) and from $131,000to $328,000 over the 3-year period. Theannual catches of the individualspecies, however, show a wide vari­ation between years with 2 years havingabout the same catch and I year havinga much greater catch. For the bigeyetuna, the catch in 1974 was almosttwice those of the other 2 years. Thecatch of yellowfin tuna in 1975 morethan tripled the ca tches of the previous2 years. The catch of albacore, alsohigh in 1975, was almost 60 times asgreat as the catch for the other years.The catch of squid reported in Table Iis the amount sold at auction andrepresents the amount caught in excessof the squid used for bait.

Bigeye tuna ca ught in this fisheryrange in size from 2.3 to 128.3 kg (5-283pounds). Frequency distributions ofweight by year (Fig. 6) show that mostof the bigeye tuna weighed less than45.4 kg (100 pounds). In 1973 fishweighing 45.4 kg (100 pounds) or lesscomprised 87.7 percent of the catch; in1974, 78.7 percent; in 1975, 71.7percent. The size range of yellowfintuna caught was from 2.7 to 125.2 kg (6to 276 pounds). The size compositionof this species varied considerably fromyear to year (Fig. 7). The medianweight is a good example of thevariability. It was 21.8 kg (48 pounds)in 1973,81.6 kg (180 pounds) in 1974,

- \

.,- ~ ~ <ol \0. ... ~.. -

_'~ __ .P"':"~..;..'" ~

Figure 4.- Photograph of a unit of handline gear.

Figure 5.-Photograph of a hook, weight, and leader of handline gear

Table 1.-Welght and value of products of night handline fishery.

Weight (t) Weight (1,000 Ib) Value ($1,000)

Species 1973 1974 1975 1973 1974 1975 1973 1974 1975

Bigeye tuna 65.4 1202 63,0 144,2 2650 139,0 1026 2498 149,5Yellow fin tuna 23.3 229 755 513 50.5 1664 380 384 157.0Albacore 04 0.2 16.1 0.8 0.4 35.5 0.5 0.2 210All tunas 89.0 143.3 154.6 196.3 3159 340.9 131.1 288.4 327.5Squid 50 1.7 1.3 ttl 37 2.8 62 35 3.5

•

/

10 Marine Fisheries Review

>- 1974u 500z'":::>fil 4000::lL

WEIGHT CLASS (kg)

Figure 6.-Frequency distribution of weights of bigeye tuna caught in thenight handline fishery for lunas.

I 51 101 251 291I II I I

260 30010 60 110

WEIGHT CLASS (POUNDS)

0.5 23.1 45.8 68.6 91.2 113.9 132.0I I I I 1 I I

4.5 27.2 49.9 72.6 95.3 117.9 136. r

Discussion

0.90, respectively. Calculations werenot made for the obviously anomalousyear of 1974.

The growth of the Hawaiian nighthandline fishery for tunas was depen­dent on two major factors: I) The in­creased demand for fresh tuna of highquality for "sashimi" (a Japanese rawfish dish) and 2) the ability of moderntransportation systems to speedilydeliver the fish to markets as much as6,400 km (4,000 miles) from the fishery.

700

1973600

500

400

300

200

100

tuna catch based on size at age infor­mation of Shomura and Keala (1963)who assumed that spawning occurredin April. Since the fishing season has itspeak half a year from the spawningseason the fish were assigned mid-yearages. The catch curves constructedfrom the data (Fig. 12) indicate thatrecruitment is complete at age 2.5 yearsand possibly a year earlier as suggestedby the data of 1973. Instantaneousrates of total mortality for fish betweenages 2.5 and 7.5 years estimated fromlines of least squares fit for 1973 and1975 resulted in Z values of 0.73 and

and 56.2 kg (124 pounds) in 1975.Albacore had a much more limited sizerange than the other species, 15.4-34.5kg (34-76 pounds) (Fig. 8). There wasone unusual individual of 3.2 kg (7pounds).

The monthly distribution of catchfor the years 1973 through 1975 (Fig. 9)show peak catches for yellowfin tunaand albacore during September andOctober, respectively. Bigeye tunacatches were more evenly distributed intime than the other species. Octoberand September were the leadingmonths.

Mention was made earlier of thehigh positive deviations in the c~tch ofbigeye tuna in 1974 and yellowfm tunaand albacore in 1975. The bigeye tunacatch of 1974 and the yellowfin tunacatch of 1975 were compared with thecatches of the other 2 years with respectto fish size and month to analyze theincrease. More specifically, the averagemonthly catch in weight for each 4.5-kg(lo-pound) weight class of 1973 and1975 was subtracted from its corre­sponding catch in 1974 for bigeye tuna;the average monthly catch for each 4.5­kg (Io-pound) weight class of 1973 and1974 was subtracted from its corre­sponding catch in 1975 for yellowfintuna.

The results for bigeye tuna (Fig. 10)show that for the months of July andAugust 1974 catch was slightly betterthan in the other years. The increase incatch was distributed fairly evenly overthe remaining 4 months of the season.Contributing most to the 1974 increasewas the December catch of 5.0- to 40.8­kg (11- to 9O-pound) fish. Other majorcontributors to the increase in order ofmagnitude were the 68.5- to 104.3-kg(151- to 23O-pound) fish in ovemberand October, and the 27.7- to 45.4-kg(61- to lDO-pound) fish in September.

The 1975 increase in yellowfin tunacatch was concentrated in the month ofSeptember (Fig. II). Two-thirds of theincrease in catch was made in Septem­ber, 17 percent in October, and 15 per­cent in November. The largest increasein weight was in the 91.2- to 113.4-kg(201- to 25O-pound) group. There wasalso a large increase in the 41.3- to 68.0­kg (91- to ISO-pound) group.

Ages were assigned to the bigeye

August /979 II

91I

100

41.31

45.4

WEIGHT CLASS (POUNDS)

23.1I

27.2

WEIGHT CLASS ( kg)

Figure 8.-Frequency distribu­tion of weights of albacorecaught in the night handlinefishery for tunas.

400

350

300

a:w 250CD::0::JZ

>- 200uzW::J0 150wa:<L-

100

50

0II

10

05I

45

291I

300

132.0I

136 I

113.9I

117.9

1975

1973

/

WEIGHT CLASS (POUNDS)

45.8 68.6 91.2I 1 1

49.9 72.6 953

23.1I

27.2

0.5I

4.5

OLI--'=''''==l'---1~~~.J::....<.~.....LL"'-±......dZ~

I10

50

100

150

200

a:wCD::0::JZ

~ZW::J

51a:<L-

WEIGHT CLASS (kg)

Figure 7.-Frequency distribution of weights of yellowfin tuna caught inthe night handline fishery for tunas.

40,---,---,-----,r-----,---,----,

30 BIGEYE TUNA

YELLOWFIN TUNA50

O'--""=..J.~......L

JULY AUG. SEPT. OCT. NOV. DEC.

Figure 9.-Proportion of indi­vidual species total caught eachmonth. Data of 1973 through1975 combined.

50

40

20

10

J:

~ 40U

::l 30

8a. 20-

'"<L-a 10t­Z

ti 0ill 60,--,-----,-----------,a.

National Marine Fisheries Service(NMFS) is now working to identify thecause of the burnt condition with thegoal of preventing it. As an interimmeasure NMFS is also working on afield method to test for burnt tunabefore the fish is sent to market.

The successful development of thenight handline fishery in Hawaiidepended heavily on knowledge ofwhere the fish are going to be and thetime of the year they are going to bethere. Similar information will be re­quired for development of nighthandline fisheries in other island com­munities.

Most of the Pacific island communi­ties are not within the network of dailyair transport schedules. Consequently,their tuna catches would have to bestored for later shipment and would beineligible for the blue chip, fresh fishmarket. Two market options wouldstill be open, however. The first, andprobably less profitable of the two, is to

One of the problems of the fishery,which is handled expediently at thelocal level and accentuated by remotemarketing, is the problem of "burnt"tuna. Tuna are labeled "burnt" whenthe normally dark red, translucentflesh is light pink, opaque, and slightlysour in taste. Burnt tuna is consideredto be less desirable than normal tunaand sells at a lower price. "Burnt,"however, is not a clear-cut condition,i.e., there is a continuum from verylightly burnt to heavily burnt. Theburnt condition cannot be detecteduntil the fish is dressed and the fleshexposed. Because tuna are transportedwhole to preserve their quality theburnt condition is not detected untilafter transportation expenses havebeen incurred. The problem is com­pounded when the seller who mustaccept the distant buyer's judgment ofquality begins to doubt the integrity ofthe buyer.

The Honolulu Laboratory of the

/2 Marine Fisheries Review

SEPTEMBER8000

132.0I

136.1

1139I

117.9

SEPTEMBER

WEIGHT CLASS (POUNDS)

45.8 68.6 91.2I I 1

49.9 72.6 953

23 I1

272

0.5I

4.5

a

1000

3000

-3000' !! !!! !!! I I I ! ! I I , ! I I I ! I I I ! ! ! I

-~[~~~k~.;~;I~, I .' I • I I I I It1 ~~EMBrn_J

I 51 101 151 201 251 291I I I I I I I

10 60 110 160 210 260 300

'":1 ••• ' • ' ••• =:= '~ ••• ~LY: •,•I:~I:- :III ••• :I i I : •••• ~A=~•J-~I Iii iii i if iii Ii; iii iii I iii Iii i

(I)o 8000z:::>

~ 7000

'"~a:'"~ 5000...~ 4000,'"....!!!~

Ii?...:I:U

~U

"'~ -1000

...o -2000zo~;;:'"o

1320I

136.1

113.9I

1179

91.2I

953

68.6I

72.6

WEIGHT CLASS (kg)

WEIGHT CLASS (POUNDS)

~-~

45.8I

49.9

23 II

27.2

0.5I

45

01 _",cr'0

-6000

-4000

Figure 1D.-Deviations of the 1974 catch from the average catch of 1973and 1975 for bigeye tuna.

6000

2~~ ;;; : ~ ~JU:LY: ;;;j~b :~ ::;; ::~ d!fA~GU~ ; j

2000

'"~'"~ -2000

"'~,'"....en

(I)o8 4000

a.

~

o -8000e: I I , I 11 l I I , ! ! ! I ! , , ! , ! I I ! I I I I I ! ! I

!~LLi~B:J~ ~c;;:,•~ :V;:ER'l

~l-=:: :;::]: 51 101 151 201 251 291

I I I I I10 60 110 160 210 260 360

:..s::

OQs::~......\Q'J\Q

WEIGHT CLASS (kg)

Figure I I.-Deviations of the 1975 catch from the average catch of 1973and 1974 for yellowfin tuna .

......w

86

" "

54

A----__

0----------<> 19731--------1 x------x 1974 f-----­

O-··_··_··-<l 1975

2000

1000

800

600

400

200

100

a- 80::>0 60a::'"~ 40a::"'CD::IE::> 20z

10

8

6

4

2

I0

AGE (YEARS)Figure 12.-Catch curve for bigeye tuna.

sell the catch to canneries. The secondis to sell the fish on the sashimi market.The latter option is available if the fleshquality of the tuna is maintained bystoring at -50°C.

Acknowledgments

The Suisan Company, Ltd., of Hilo,Hawaii, provided the catch and pricedata. I gratefully acknowledge the will­ing assistance of Zenso Kanai and HiroNishimura of Suisan Company, Ltd.Kanai made the records available.Both made arrangements for me tointerview fishermen and to board fish­ing boats for field observations.Howard Takata, Marine Advisory

Agent in Hilo, made a conscientiousreview of the manuscript.

Literature Cited

Otsu, T. 1954. Analysis of the Hawaiian long­line fishery, 1948-52. Commer. Fish. Rev.16(9): 1-17.

Shomura, R. S., and B. A. Keala. 1963.Growth and sexual dimorphism in growth ofbigeye tuna (Thunnus obesus) a preliminaryreport. In H. Rosa, Jr. (editor), Proceedingsof the World Scientific Meeting on theBiology of Tunas and Related Species,2-14 July 1962. FAO Fish. Rep. 6, vol 3,p. 1409-1417.

United Japanese Society of Hawaii. 1971. Ahistory of Japanese in Hawaii. PublicationCommittee, United Japanese Society ofHawaii, J. Okahata, Chairman, HonoluluXIX, 431 p.

/4 Marine Fisheries Review

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