synopsis of biological data on albacore thunnus … synopsis no, 9 fao fisheries biology synopsis...

Species Synopsis No, 9FAO Fisheries Biology Synopsis No, 52 FJb/S52(Distribution r estricted) SAST - Tuna

SYNOPSIS OF BIOLOGICAL DATA ON ?LBACOREThunnus germo (Lacépède), 1800 (PACIFIC AN5ÏAN OCEANS)

Exposé synoptique sur la biologie du germonThunnus germo (Lacépède), 1800 (Océans Pacifique et Indien)

Sinopsis so1re la biologfa de la albacoraThunnus germo (Lacépède), 1800 (Oceanos Pacifico e Indico)

Prepared byHOWARD O, YOSHIDA AND TAMIO OTSU

U. S, Bureau of Commercial FisheriesBiological Laboratory

Honolulu, Hawaii

FISHERIES DIVISION, BIOLOGY BRANCHFOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONSRome, 1963

2 7L

FAO LIBRARY AN: 052715

FIb/S52 Albacore 1:1

1 IDENTITY

1. 1 Taxonomy1. 1. 1 Definition

Classification down to family after Schultz,et al 1960.

Phylum CHORDATASubphylum CraniataSuperclass GnathostomataClass OsteichthysSubclass TeostomiSuperorder TeleosteicaOrder Percomorphida

Suborder ScombrinaFamily ScombridaeGenus Thurmus South 1845

Species germo (Lacpbde),

1,1. 2 Description

- Genus Thunnus South 1845

"Body moderately robust; snout pointed, notvery long; mouth rather large; maxillary notconcealed by preorbital; teeth in jaws small,those on vomer and palatines in villiform patches;gill rakers long, moderately slender; scalescovering entire body, enlarged, and forming acorselet in region of pectorals; interval be-tween dorsal fins slight; first dorsal with 12 to15 rather slender spines, the fin high anteriorly;second dorsal and anal each followed by 8 or 9finlets; ventral fins rather small, less than halflength of head; pectoral short or long, with about32 to 35 raya." (Hildebrand, 1946).

- Thunnus germo (Lacpde) 1800

"Body elongate, fusiforrn; caudal peduncleslender, keel on each side. Head conical; mouthterminal, moderate; gill rakers below angle offirst gill arch, 19 to 21. Fins: dorsal (2), XIIIor XIV - II, 13 or 14, interspace very short,spinous fin long, high anteriorly, finlets 7 or 8;anal, II, 12 or 13, origin below insertion ofrayed dorsals, finlets, 7 or 8; pelvic I, 5,thoracic; pectoral very long, longer than head,reaching behind insertion of anal fin, sabre-shaped; caudal lunate. Lateral line: decurvedanteriorly, nearly straight for greater part oflength. Scales: cycloid, moderate, coveringbody; corselet small, indistinct. Color:metallic steely blue on dorsal surface and sides;silvery on ventral surface." (Clemens andWilby, 1946). (Fig. 1).

275

The internal anatomy of the albacore hasbeen studied in great detail by Godsil and Byers(1944) and Kishinouye (1923). Excerpts fromtse studies are presented below.

"The view of the viscera in situ is strikinglydifferent from that of any other tuna investigated.The course of the intestine from right side toleft across the, abdominal cavity, the locationof the spleen on the left side, and relativelyconspicuous position of the gall-bladder serveto distinguish this tuna from any other.

"The center lobef the liveis always the1onget, and the outline of all lobes is quiteirregular, due to extensive lobulation. Theventral surface of all lobes is always marked'with characteristic radiating striations, andlarge conical vascular cones are invariablypresent on the dorsal face of each lobe. Thereare generally two moderate cones beneath theright lobe, one large one beneath the centerlobe, and four or five small ones beneath theleft lobe.

"In the albacore the straight intestine, inventral view, appears anteriorly upon theright side of the fish, but in the anterior halfof the abdominal cavity it crosses to the left'side. Both anterior and posterior bend, andin consequence the fold of the intestine, arelocated on the left side of the abdominal cavity,and the descending portion of the intestine runsto the vent against the left wall of the bodycavity.

"In shape and location the spleen of thealbacore differs from that of the remainingtunas. This is the only species in which thespleen appears on the left side of the abdominalcavity.

"Due to its location, the gall-bladder is aconspicuous and distinctive character in thealbacore. It follows closely the course of thestraight intestine from its apparent originanteriorly on the right side. Crossing withthis to the left side of the fish it continues pos-teriorly beyond the posterior bend of theintestine. It lies on the median side of theintestine as a tubular, green structure and canrarely be overlooked.. A short distance beyondthe posterior bend of the intestine, the gall-bladder doubles anteriorly upon itself and,reaching the bend of the intestine, terminateshere or occasionally again doubles back uponitself." (Godsil and Byers, 1944)

Fig. i Thunnus germo (Lacépde) (reproduced from Waiford, 1937)

1:2 FIb/S52 Albacore


"Skull rather narrow. Vertebral columnmore or less slender. Height of the vertebraenearly uniform. Parapophyses well developed.Parapophyses of the ninth vertebra are almosthorizontal as in the preceding vertebrae; but inthe tenth vertebra the haemal arch is formed andis turned forward leaving only a little space be-tween the centrurn and the arch. In each of thefollowing precaudal vertebrae the haemal spineis formed, and it is remarkable that it is nearlyuniformly elongated. These precaudal haemalspines are remarkably longer than in othertunnies. The head of the second and third ribsis very thick, and the distal portion of theseribs is broad, thin, and gradually narrow, Thepart between the head and the broad distal por-tion is very narrow to admit the passage of thecutaneous blood vessels. " (Kishinoùye, 1923)

1. 2 Nomenclature

1. 2. 1 Valid scientific name(s)

Thunnus gerrno (Lacpbde)

It should be mentioned here, without delvinginto the details., that the validity of this namehas not been verified. Collette (MS) and Roedeland Fitch (MS) have discussed the problems con-cerned with the taxonomy and nomenclature ofthe tunas in some detail.

1. 2. 2 Synonyms

Collette (MS) has compiled a list óf synonymsof the albacore. The names that have been ap-plied to the albacore in the Pacific and IndianOceans are listed below.

Scomber germo Lacpède 1800Thynnus pacificus Cuvier in Cuvier and

Valenciennes 1831Thunnus pacificus South 1845Orcynus pacificus Cooper 1863Orcynus germo Lìtken 1880Germo alalunga Jordan and Everman 1896Germo germo Jordan and Seale 1906Thunnus alalunga Jordan, Tanaka and

Snyder 1913Thunnus germo Kishinouye 1923

277

1 . 2. 3 Standard common names,vernacular names

The common and vernacular names listedin Table I were drawn primarily from the listcompiled by Rosa (1950).

1.3 General variability

1. 3 1 Subspecific fragmentation(races, varieties, hybrids)(see also section 1. 3. 2)

- Meristic counts

Meristic counts on albacore from variouslocalities are presented in Tablé II.

- Varieties

Godsil (1948) compared albacore fromCalifornia and Japan and noted that "theJapanese albacore are characterized by arelatively shorter head and caudal regionand a longer abdominal or central trunk."

Kurogane and Hiyama (1959) comparedalbacore taken from several differentlocalities. They found that the albacorefrom the Indian Ocean had larger heads andmuch posteriorly positioned fins than albacorefrom the northwest Pacific. Also, they con-cluded that albacore from the Indian Oceanand the southwest Pacific Ocean did not forma homogeneous population because of therather great differences between them.However, the difference was not as great asthat between the albacore in the Indian Oceanand the northwest Pacific. Therefore, theyfurther concluded that there existed a pos si-bility of intercourse between the populationsin the Indian Ocean and the southwest PacificOcean.

Table ICommon and vernacular names

278


StandardCountry common naine Vernacular name(s)

Australia Albacore

Canada Albacore Longfin albacore, Longfin tuna

Chile Atun de aleta larga Atun

Hawaii Albacore Longfin albacore, Ahipalaha

Japan Binnaga Bincho, Toinboshibi, Kantaro

Mexico Albacora

New Zealand Longfin albacore

Peru Alalonga

Philippines Albacore Albakora. (Tagalog), Kiyawon . (Bikol)

Union of South Africa Albacore Longfin albacore, Longfin tunnyLongfin tuna

United States Albacore Longfin albacore, Longlin tuna,Albacora, Alllónghi, Germon,Abr ego

Table IIMeristic counts of albacore

Locality7 8 9 10 18 19 20 21 22 25 26 27 28 29 30 31 32

Note: Japan, Hawaii, and California data from Godsil arid Byers (1944); Indian Ocean,

Northwest Pacific, nd, Southwest Pacific data from Kurogane and Hiyama (1959).

1. 3. 2 Genetic data (chromosomenumber, protein specificity)

Suzuki, Mono and Mimoto (1959) discovereda blood group system designated Tgl - Tg2 - Oin the albacore. Sprague (MS) discovered anotherblood group system designated the G- system.Other systems that have been recognized in thealbacore are the A-system and C-system (Spragueand Nakashima, MS).

The blood group characteristics have beenutilized in studying the problem of sub-populationsof albacore. Suzuki, et al (1959) compared theblood group frequency of albacore from the NorthPacific and Indian Oceans and found strikingdifferences between the two,, Marr and Sprague(MS) subjected the data from Suzuki, 4 to

279

another analysis and concluded that thePacific Ocean samples were drawn from asingle inter-breeding population, but thatthe Indian Ocean samples were drawn froma mixture of two or more inter-breedingpopulations.

Sprague (MS) noted that the differencein the relative proportions of pheno-typesof C-positive albacore from Samoa andNorth America was highly significant andconcluded that the albacore from the twoareas are representative of geneticallyisolated stocks.

JapanHawaiiCaliforniaIndian OceanNorthwest PacificSouthwest Pacific

-

1

25

-352

123852

128

255866

--

-44

1-1-41

1

-

714

23

5

3

7205971

2

3

102429

i113--

Locality istdorsal

fin

2nddorsal

finDorsalfinlets

2nd dorsal finplus

dorsal finletsAnalrin

Analfinlets

Anal finplus

Anal finlets

13 14 15 16 78 22 23 1415 78 21 22

JapanHawaiiCalifornia

- 91 23 8

25- 3

3 7

6 3

3

8 3

1 6- 3

lO

27-31 10

813-10 1

1 83

- 11

Locality1st dorsal spine

12 13 14 15

Indian OceanNorthwest PacificSouthwest Pacific

39 84 -3 74 206 1

- 53 127 -

'Ib/S52 Albacore 1:5

1 1 51.1 2 -2 63

- 5 9 15 8 1

1 8 32 44 12 3 1

2 14 41 45 232,

2 DISTRIBUTION

2. 1 Delimitation of the total area of distri-bution and ecological characterizationof this area

The distribution of albacore in the Pacificand Indian Oceans is shown in Fig. 2, which wasadapted from Fig. 11 of Brock (1959a). It can beseen from this chart that albacore is quite cosmo-politan in distribution. On the eastern side of theNorth Pacific, albacore has been recorded fromBaja California to the Gulf of Alaska. In thewestern North Pacific albacore is distributed fromthe Equator to approximately 45° N latitude.Centered approximately along 35° N latitude,albacore has a continuous distribution across theNorth Pacific Ocean.

In the South Pacific, albacore has been re-corded from the Equator to 45° S latitude andfrom the east coast of Australia to the coast ofChile. However, the occurrence of albacore fromabout 135° W longitude to the coast of Chile isquite spotty.

The range of distribution of albacore in theIndian Ocean is from approximately 100 N to 30° 5latitude and from Australia to the east coast ofAfrica.

1/ Data from files of 11. &Laboratory, Honolulu,

Table LIIOccurrence of larval albacore!"

Hawaii.Bureau

The major oceanographic features of theseareas were described in a general way byBrock (1959a). Figs. 3, 4, 5, 6, and 7 wereadapted from Brock and show the ocean currentsystems, summer average surface temperatureand depth of thermocline, winter average sur-face temperature and depth of thermocline,respectively.

2. 2 Differential distribution

280

2. 2. 1 Areas occupied by eggs, larvaeand other junior stages; annualvariations in these patterns,and seasonal variations forstages persisting over two ormore seasons. Areas occu-pied by adult stages: seasonaland annual variations of these

- Larval stages

There is very little information on thedistribution of larval albacore. Table IIIlists some records of the occurrence of larvalalbacore, based on the tentative identificationof Matsumoto (MS),

No. of Albacore larvae

i259

ii2

4i1

51

of Commercial Fisheries Biological

May 1929 20'04' N l2359' EMay 1929 25°30' N 12528' EJune 1929 14s37t N 119 °52' EJuly 1929 0050' S 13415' ESeptember 1929 01°29' S 10007' EOctober 1929 02S57t S 99'36' ENovember 1929 0420' N 98°47' EJanuary 1952 0l'54' N 155°03' WMay 1952 01'57' N l40°0' WMay 1952 03°09' N 139a531 WNovember 1957 09'13' S 141 35' WFebruary 1958 02°10' S l4408' WFebruary 1958 07'12' S 14210' WMarch 1958 06Z0' S 139°39' WMay 1958 0912' S l4308l WMay 1958 09°14' S 14220' WJuly 1960 0905' N 16820' E

FIb/S52 Albacore 2'l

Date Position

4o

Io

Io

4O

k J (

iÍiIiIlIiiiali"!"

cl'.AI Uj

r

/z7 Ø// '//

7

9%4

r,7,%,

i

f

/6

4O 0? 6O 7 0? 90? 1017

ri.I."I 0? 217 1317 417 517 617 717 817 1717 617 517 1417 377

Fig. Z Distribution of albacore in the Pacific and Indian Oceans (Brock,. 1959a)

NOiEQUATÖF8AL

COUNTERCURRENT

UI.....WEST WIND DRWT

40?

0?

0?

40?

50

477 517 60? 777 80? 917 017 1117 277 130 1417 517 617 717 877 I70 617 517 417 377 217 1177 1017 817 80? 70? 60?677

40?

177

20?

40?

Fig. 3 Ocean current systems (Brock, 1959a)

281

217 110? 017 867 8(7 70?

50?

0?

10?

20?

2:2 'FIb/S52 AJ,bcore

60?477 317 217 110? 017 977 817 70?817 717 160? 577617 71715171317100? 60? 70? 60? 90? 100? 110? 12

17 01741750? 60? 717 817 517 017 1117 1217130? 1417 1517 617 17171817 777 617 sC 80? 70? 60?1517 417 I30 I2O

Fig. 4 Summer (August) average surface temperature (°F) (Brock; 1959a)

Fig. 5 Summer (August) depth of thermocline (feet) (Brock, 1959a)

282

4O

ÍU!!!ii.Il.u.

\

---...-'1t!iiUi ¡40' co' so ro' so. so. ioo. ib' 120' izo' so. so' iso' ro' iso' ro' so' loo. iso. izo. 20' io. co. so. so. ro. so'

ìiìiTuuiÍ'Aii:

Fib/S&2 Albacore 2:

4O 5O 6O ro. So. 9O ioo. iso. izo. izo. 14o. lOo. iso. i7O l8O l7O ISo. I5C iso. izo. izo. ii. ro.

2O

jo.

20

40

2o.

Io,

lo.

20'

4O 5O 6O 7o. 8O 9O ioo. Io. I2O I3O 14o. iso. ISO 17o. iso. iTO iso. iso 14o. loo. 12o. io. IOO 9O So. 7o. so.Go.

II&

Ld L . ìUUi.iU

'Io. 50'SO' 70' 80' 90' lOO' IO' IZO' I30' i40' IO' ISO' .i70' ISO' 70' i6O 50' 40' 30' I20' hO' 00' S0'80' 70' 50'

50'

Fig. 6 Winteì (February) average surface temperature (°F) (Brock, 1959a)

4o. so' so' To' so. so' ioo' lo. loo. 30' 140G isO' 60' 170' iSO' 170' iso. IZO' i4o. 30' loo. lo. loo' so. so' 70' 60'

Á1I1NLIii470' il

20' -& 1UL1iJÁ l

o. FIUIiPJ1)40' so. so' 75io. 90' ioo. IO' 120' 130' 140' ISO' 1GO' 170' 180' 170' 160' ISO' ISO' 130' 120' 110' loo. 90' 80' 70' 60'

50'

40'

30'

20'

io'

O'

Io'

20'

30'

40'

Fig. 7 Winter (February) depth of thermocline (feet) (Brock, 1959a)

283


40'

30'

20'

lo'

o'

io.

20'

30'

40'

so'

Z. 3 Behavioristic and ecological determi-nants of the general limits of distribu-tion and of the variations of these limitsand of differential distribution

Radovich (1961) states, "It appears that Paci-fic albacore distribution along the North Americancoast is influenced by the environment, of whichtemperature is a strong indicator if not a primaryfactor in itself." According to Radovich, about65 percent of the albacore caught by the Californiafishery from 1954 through 1956 were from waterwith surface temperatures between 600 - 640 F.

Clemens (1961) indicates that the movementof albacore along the west coast of the UnitedStates is regulated primarily by sea-surfacetemperatures between 580 - 680 F. Accordingto Clemens, the area where the albacore movesinto the fishing grounds shifts north and southwith warming and cooling sea-surface tempera-tures.

28L

In the area bounded by 160° W and the 180thmeridian in the North Pacific, McGary, Graham,and Otsii (1960) showed that, during the winter,the latitudinal limits of the distribution of albacorewere almost coincident with the southern boundaryof the Transition Zone.

The Japanese believe that the devlopment ofthe surface summer albacore fishery off the coastof Japan is controlled by the way in which theseasonal warming of the area by the Kuroshioprogresses (Van Campen, 1960).

In the western South Pacific, Yamanaka(1956) suggests that a "discontinuity layer withconsiderable convergence which is found extend-ing from east to west in the neighborhood oflatitude 10° S" plays an important part as anorthern limit in the distribution of the SouthPacific albacore.

3 BIONOMICS AND LIFE HISTORY

3. 1 Reproduction

3. 1. 1 Sexuality (hermaphroditisrn,heterosexuality1 intersexuality)

The albacore is heterosexual. There areno external characters known to distinguishbetween the males and females. A case of her-maphroditism was cited by Legand (MS) in analbacore taken iii waters off southwestern NewCaledonia, but details were not given.

3. 1. 2 Maturity (age and size)

It was first reported by Ueyanagi (1955) andlater supported by the findings of Otsu andUchida (l959a) that female albacore attain sexualmaturity and thus n-lay first spawn at about 90 cmin length. The smallest mature fish found insamples collected from the western Pacific(Ueyanagi, 1957) was 87 cm long, and the smal-lest from the central equatorial Pacific mea-sured 89. 1 cm (Otsu and Uchida, 1959a). Otsuand Hansen (1961) reported in their study of thecentral South Pacific albacore that some fishare already mature at 86 cm.

As for the males, Ueyanagi (1957) judgedfrom their general appearance and oozing ofmut that testes weighing more than 150 gramswere probably ripe. From this, he postulatedthat the smallest mature fish measured 97 cm.Following the same criteria, Otsu and Hansen(1961) found that some male albacore are pro-bably mature when they attain a length of about90 cm. However, lacking more objectivemeans of determining maturity of the males, itcannot be said with certainty that this is thesize at which male albacore are first capable ofspawning.

The age at maturity has not been satisfac-torily determined for the albacore. Suda (1958)has postulated that spawning albacore are age-VI and older. Otsu and Uchida (MS) hypothesizedthat the 6-year-olds (94 cm) and older agegroups move south from the Japanese winter

285

longline fishery into sub-tropical waters to formthe reproductive unit of the North Pacific popu-lation.

3. 1, 3 Mating (monogamous, polyga-mous, promiscuous)

No records of observations on spawningfish are available. However, imminentlyspawning albacore more than likely occur inaggregations and male and female fish probablyrelease their sex products indiscriminatelywithout specifically seleçting any particularpartner or partners.

3. 1.4 Fertilization (internal, external)

External. The eggs of the female and themilt of the male are discharged into the water,where the eggs are fertilized. The eggs andlarvae are believed to occur in surface layers.

3. 1. 5 Fecundity

Estimates of fecundity were based on theassumption that all the eggs comprising themost advanced group within an ovary werereleased in a single spawning (Ueyanagi, 1955and 1957, and Otsu and Uchida, 1959a). Theseestimates ranged between 0. 8 and 2. 6 million.eggs.

- Relation of gonad size andegg number to body size andto age

Otsu and Uchida (1959a) noted only a slighttendency for larger albacore to have more eggsper spawning.

3. 1. 6 Spawning

- Spawning seasons (beginning,end, peak)

The spawning season of albacore has notbeen defined in detail. However, on the basisof seasonal changes in gonad maturity,Ueyanagi (1957) inferred that spawning in thewestern North Pacific occurs in subtropical


3:2 FIb! 352 Albacore

waters during the summer months with Juneand July at its peak. Otsu and Uchida (1959a)also found evidence of spawning through examin-ation of gonads of albacore taken in Hawaiianwaters during the summer. The most highlydeveloped ovaries were collected during Juneand July. From these results, it'is believedthat albacore spawning in the North Paáificoccurs largely during the summer months inareas under the influence of the North Equator-ial Current, and that the spawning grounds maybe over a broad area extending to as far east asthe Hawaiian Islands. The determination ofthe exact spawning period will have to awaitfuture field work which will involve the study ofthe seasonal distribution of larval albacore.

In the South Pacific, Otsu and Hansen (1961)found that the seasonal progressior in gonaddevelopment peaked during December, Thegradual increase in the proportion of late de-veloping ovaries in the monthly samples fromthe low point in May to a peak in December,with a gradual decrease thereafter, suggestedthat spawning mu8t take place during thesouthern summer months. Depending upon therate of ova development, albacore may bespawning during only a portion of that period,and that portion may be towards the end, per-haps between January and March, when thepercentage of late developing ovaries is de-creasing. At any rate,. the spawning season inthe South Pacific is six months out of phase withthat in the North Pacific. The spawning groundsappear to cover a broad area between theEquator and 200 S latitude. East-west differ-ences in spawning activity were not discerniblewithin the extent of the area sampled (130° W -1600 E ).

Ishii and moue (1956) reported on results ofexamination of ovaries of albacore taken in theCoral Sea (170 S - 20° S, 152° E - 153° Ein January 1954. The authors postulated thatthe Coral Sea and the adjacent New Caledoniaareas are spawning areas for the albacore.More recently Legand (MS) studied theseasonal trend of the ovary volume to bodylength relationship of albacore taken in waterswithin 200 miles of the southwest coast ofNew Caledonia (210 30' S - 24° S) anl

286

reported that albacore spawning probably occursin the summer (December-January).

In the Indian Ocean, Ueyanagi (1955) reportedon highly developed ovaries obtained from albacoretaken from waters south of Sunda Islands inFebruary 1953. He concluded that, "The seasonand area of spawning have never been known con-cerning the albacore distributed in the IndianOcean. It is now clear from the above findingsthat the spawning of this fish takes place inFebruary at least in part.

- Number of spawnings per year(frequency)

Very little study has been conducted on thefrequency of spawning in the albacore. The fre-quency distributions of egg diameters in alba-core ovaries show clearly two or more modeswhich, depending on the growth rate of the egg,may represent eggs that will be spawned in asingle season or in succeeding seasons. Otsuand Uchida (1959a) postulated from the presenceof egg remnants in late developing ovaries thatthis species may undergo multiple spawning.The presence of egg remnants together with agroup of eggs approaching ripeness suggestedthat albacore may spawn at least twice duringa single spawning season. Further evidencealong this line was obtained from the fact thatremnants were absent in large, sexually inactiveadults taken during late winter in the NorthPacific, a suggestion that remnants are not car-ried over from one year to the next. However,in the absence of any knowledge regarding therate of i esorptioil of the unspawned eggs, nodefinite conclusions can be drawn.

- Induction of spawning, artificialfertilization

No instance of successful artificial fertili-zation in albacore has been recorded. Amongthe tunas, however, Kikawa (1953) and Kume(MS), both of the Nankai Regional FisheriesExperimental Station in Kochi, Japan, were ableto artificially fertilize bigeye tuna eggs. In thelatter experiment, conducted in 1961, the-eggswere successfully hatched but the larvae soonsuccumbed to mortality.


These experiments point out the possibility ofartificial fertilization in albacore.

3. 1. 7 Spawning grounds

- Coastal (surface, vegetation,shore, shoal, sand, shelter);bottom

Albacore spawning is believed to take placein oceanic rather than coastal waters.

- Oceanic (surface, bottom)

As in other tunas, the albacore spawns inoceanic waters, The best information availableindicates that spawning takes place in tropicaland subtropical waters of both the Pacific andIndian Oceans. There is no evidence of temper-ate water spawning.

3.1.8 Egg: Structure, size, hatchingtype, parasites and predators

The most highly developed ovarian eggsrecorded from the Pacific and Indian Oceanswere found in albacore taken in waters aroundthe Hawaiian Islands and Sunda Islands, respec-tively. Thèse ovaries, although very highlydeveloped, were not fully ripe. They containedeggs which measured about 0. 8 mm in averagediameter and the largest measured about 1 mm(tJeyanagi, 1955; Otsu and tjchida, 1959a). Ripealbacore eggs are therefore about 1 mm indiameter.

The immature oocytes under about 0.2 mmin diameter, which cannot be seen with thenaked eye, are polygonal, colorless, and trans-parent, and fixed specimens stain deeply withhernatoxylin. These oocytes, also referred toas "primitive eggs," are found in ovaries inall stages of development. In early develop-ment, the eggs increase in size and becomesemi-opaque from deposition of yolk granules.The maximum diameter of eggs in this stage isabout 0, 4 mm. With further development, theeggs become completely opaque from the heavyaccumulation of yolk granules and the diameternow ranges from 0.4 to about 0.8 mm. Dis-tinct changes occur in the eggs as they approachripeness. They lose their opacity and becomesemi-transparent; the nucleus cannot be de-tected at this stage, and a conspicuous golden-yellow oil globule appears.

There are no records of capture of albacorewith "running ripe" ovaries in the Pacific

287

and Indian Oceans. Furthermore, it is notpossible at present to satisfactorily distinguishbetween the pelagic eggs of the several speciesof tunas. In the Mediterranean Sea, Sanzo(1933) described the pelagic eggs of Orcynusgermo Liitken =? Thunnus alalunga (Bonna -terreJ taken in plankton net hauls in theStrait of Messina. He found the eggs, between0.84 and 0.94 mm. in diameter, to be buoyant.spherical, and'highly transparent. The oilglobule, which was always single, measuredaround 0. 4 mm. Matsurnoto (MS) in discus-sing Sanzo's description of the larvae whichwere successfully hatched from these eggs,cautioned that although the plankton collectionswere made during specific migratory runs ofthe species through the Strait, there was riodefinite assurance that the eggs of one specieswere collected exclusive of the other specieswhich are also known to spawn during the sameperiod.

No information is available on the hatchingtype, parasitic infection, and predation onalbacore eggs.

3.2 Larval history

3.2.1 Account of embryonic and ju-venile life (prelarva, larva,postlarva, juvenile)

No information on the embryonic (prelarva)stages of albacore is available from the Pacificand Indian Oceans. Sanzo (1933) reported on theova and early larval stages of Orcynus germo(Litken) L? Thunnus alalunga (Bonnaterre)from the Mediterranean Sea. Sanzo collectedthe fertilized ova in the Strait of Messina andwas able to hatch the ova, and to rear thelarvae up to seven days in bis laboratory. Asmentioned in section 3.1. 8, however, there Issome question whether Sanzo really reported onthe ova and early larval stages of albacore oranother species.

Recently Matsumoto (MS) was able to maketentative identificatiox. of larval albacore fromamong the larval tunas collected on the "Dana"expedition during 1928-30 (Fig. 8). Accordingto Matsumoto, the larvae of albacore differfrom those of yellowfin (Neothunnus macropterus)in having two chromatophores along the ventraledge of the body on the a8th and 33rd myotornes.Furthermore, the distinctive character whichsets the albacore apart from bigeye (Parathunnussibi) and yellowfin is the single chromatophore

ihe dorsal edge of the trunk.

- Feeding

Sanzo (1933) reported that between thesecond and third day after hatching the larvaebegan pecking on the bottom of the rearing jar.

- Rates, of: development andsurvival

The earliest stage of the developing zygotethat Sanzo was able to obtain was the stage of theclosure of the blastopore. According to Sanzo,at this stage, the embryo extends halfway aroundthe full circumference of the egg; the cephalicregion is rather large; the secondary oticvesicles are formed, the otocysts, and about 10muscle segments are present. After about 7 or8 hours, the embryo has the tail developed to agreater length, turned upward and forward overthe anterior surface of the oil globule, and about40 segments can be counted. The embryonicdevelopment takes place in two days.

Table IV

288

The development of thé larva immediatelyafter hatching is summarized in Table IV.

- Periods of: development andur viva i

(See section on rates of: development andsurvival).

- Parental care

Although no direct observations have beenmade, the young are most likely left to fend forthemselves.

- Parasites and predatorsKishinouye (1923) states, uI found a young

germon about 30 cm In length in the Btomach ofa large germon,' caught on January 20th, 1917near the Ogasawara Islandsa and other smallones from a yellow-finned tunny and a spearfish caught on February 27th of the same year. "


The development of the larvae immediately after hatching(adapted from Sanzo, 1933)

Thne after hatching Development

let hour The mouth opening is not yet formed; all signs of the branchialekeleton and the pectoral fins are lacking; the primordial fin fold israther low anteriorly on the back; the eyes are without pigment; 10specimens averaged 2. 60 mm in length.

On the day after hatching The primordial dorsal fin has become quite high anteriorly and ex-tendB to opposite the otic region; the mouth Is not yet open; the hearthas already rotated from its embryonic position; very small pectoralshave made their appearance; one specimen at this stage measured2. 96 mm.

At the end of the first day The stornodeum is in process of formation; the pectorals ae slightlyenlarged; specimens measured from 3. 20 - 3. 50 mm in length.

On the 2nd day The mouth opening is formed; Meckel's cartilage is present; thehyoid and branhia1 apparatus are differentiated; the eye is roundedand has incipient pigmentation.

2 to 3 days The eyes are completely pigmentated.

On the 5th day Primordial fins greatly developed; two large olfactory pits on snout;the eyes are large and slightly subroturid- posterior to them are twolarge otocysts with the semicircular canals differentiated.

After the 5th day The larvae begin to reduce in length.

On the 7th day The primordial fin is reduced; one specimen measured 3. 20 mma toothlet present on upper jaw.

FIb/S52 Albacore

Table V lists other occasions of predation onjuvenile albacore as reported by Yabe, Tjeyanagi,Kikawa and Watanabe (1958).

3. 3 Adult history

3. 3. 1 Longevity

Uchida and Otsu (MS) indicate that thereare about 10 age groups composing the Japanesewinter longline fishery, of which the oldest groupis 10 years old. The albacore that are caught inthe Hawaiian Islands grow to a greater size (seeFig. 19). Uchida and Otsu did not attempt anyage analysis o Hawaiian albacore "because ofinaccuracies which may result from possible dif-ferential growth between the sexes in such largefish."

3.3.2 Hardiness

The fact that albacore survive after experien-cing the handling involved in tagging and then goon to make trans-Pacific migrations may indicatethat they are quite hardy.

Clemens (1961) says, "After having taggedseveral tons of albacore, yellowfin tuna, andskipjack, and, a few bluefin and bigeye tuna, Ibelieve that albacore are the hardiest of the fivefollowed by bluefin, bigeye, yellowfin and skip-jack.

Table V

Some records of predation on juvenile albacore(Yabe, et al 1958)

289

3. 3. 3 Competitors

Iversen (MS) reported that, "the sImilari-ties in diet between both the albacore and theyellowfin and albacore and the bigeye in the samespecific location, as well as in the same generalarea, are evidence that there is some competi-tion between the albacore and the other twospecie s of tuna."

In the area near New Caledonia, Legand andWauthy (MS) noted that "albacore and ,Alepi-saurus compete in many ways for food".

3.3.4 Predators

Kishinouye (1923) made some generalremarks on the enemies of scQrnbroid fishes.He says, "The gigantic species of the scorn-broid fishes-have few enemies. Their mostdreaded enemies are dolphins, especially thekiller. Killers often await the passage oflarge schools of tunnies in a strait, such asTsugaru Strait, and attack them furiously.

Bennett (1840), in speaking of albacore,says, "It is, probably, as a protection fromtheir chief enemy, the sword-fish, that theyseek society of a ship. I am not aware that theshark is also their enemy; but they seemed tohave an instinctive dread of this large fish,when it approached the ship, would follow it in

3:5

Albacorebody length Date Locality Predator

188 mm 5-15 -49' l838' N 15P26' E. Black marlin124 mm 6-11-52 2057' N 14936' E Black marlinca 170 mm 2-1-55 l844' S l7654' E Yellowfinca. 170mm 2-2-55 l858' S l76°27' E Yellowfin234 mm 12-6-56 20°50' S 155'30' E Striped marlin258 zum 3-20-57 2513' S 99G431 E Shortnosed spearfiøh


shoals, and annoy it in the same manner as thesmaller birds may be seen to annoy those of alarger and predaceous kind, as the hawk or owl,However, as mentioned in section 3. 3.6 there issome doubt whether Bennett was really reportingon albacore.

Tunas, including albacore, caught by long-lines are often damaged by sharks. It is notknown whether sharks normally prey on tunas.Strasburg (1957) presents some lines of evidenceto indicate that sharks may swim fast enough tocatch free-swimming tuna. He says, "For onething both species of sharks (silky and whitetip)are occasionally caught on trolling lines atvessel speeds of 6 to 8 knots, and for another,one bigeye tuna captured alive bore a pair oflarge U-shaped scars suspiciously resemblingshark jaws in shape. '

3. 3. 5 Parasites and diseases

Table VI lists records of infestation of alba-core by various parasites in the Pacific Ocean.

3.3.6 Greatest size

The International Game Fish Association(1960) lists the world record for albacore, whichwas caug1t in the Atlantic Ocean, as 69 lbs.

Table VI

Parasites of albacore

Parasite

Elythrophora brachypteraHirudinella spinulosaDidymocystis alalongaeDidymocystis opercularisPlatocystis alalongaeMelanematobothrlum guerneiAnisakis sp.Contracaecu.m legendrei

Location of infestation

Inner surface of operculumStomachGill archOperculumOn skinIn sub-maxillary muscle

Stomach

R efe r e nc e

Yamaguti (1936)Yamaguti (1938)

ii Iit, t,

ti it

Yamaguti (1941)it ti

290

In the Pacific Ocean, it lists an albacore weigh-ing 66 lbs. 4 oz asthe largest caught by a sportfisherman. According to a table of length-weightrelation, albacore weighing 66-69 lbs would beapproximately 115-118 cm in length. Albacoreof this size are commonly caught by longlinesaround Hawaii (see Fig. 15). Apparently, thealbacore .occurring around Hawaii are the largestin the Pacific Ocean, and the largest specimenrecorded is the one reported by Otsu and Uchida(1959a), which weighed 93 lbs and measured128 rn in length.

Bennett (1840) made some observations onthe size of albacore. He noted that, "Theaverage length of the examples we captured fromthe ship was four feet; though some others, whichwe saw on the coasts of the Polynesian Islands,measured nearly six feet. " However, it israther dubious that Bennettreally saw albacoreTtnearly six feet, "(or 189 cm). It i8 doubtfulthat albacore ever grow to anywhere near thissize.

3.4 Nutrition and growth

3.4. 1 Feeding (time, place, manner,season)

Iversen (Ms) indicated that toll-caught alba-core in the temperate North Pacific feed

throughout the day. He also presented someevidence to indicate that albacore are able tofeed at night. Iversen found, however, that alba-core caught during hours of darkness by gilinetshad smaller stomach volumes. He suggeststhat this is due to less successful foraging byalbacore at night.

3.4.2 Food (type, volume)

In a study of albacore food in the South ChinaSea, Kanamura and Yazaki (1940) found squid,octopus, stomatopod8, barracuda, "hairtall,""flatheads," ginkagami (Mene rnaculata), and"sardine" (Bathylagus nakazewai) in the stom-achs of albacore.

Powell (1950) noted that small rockcod con-stituted the bulk of the food of albacore taken inthe northeastern Pacific with squid, saury,small blackcod, and lantern fish present invarying amounts.

McHugh (1952) studied the food habits oftroll-caught albacore off California and BajaCalifornia, and reported that, "By far the mostimportant item was the Pacific saury (Cololabissaira), which constituted alrriost 50 percent ofthe total food volume. Next in order of impor-tance were squids (12 percent); Pleuroncodesplanipes, the pelagic decapod of southern waters(11 percent); euphauslids (7 percent); and thenorthern anchovy, Engrau]1s mordax mordax(4 percent)."

Barracuda, a specie s of "sand borer," andOstracion, diaphanus (=Lactoria diaphanus) werefound in stomachs of albacore caught by longlinesin waters around the Bonin Islands (Yabuta, 1953).However, Yabuta noted that albacore fed mostlyon crustaceans and small cephalopods.

In the western Indian Ocean, Koga (l958a)found that the following were found in 10 percentor more of the albacore stomachs examinedTriacanthidae, Plagyodontidae (= Akepisauridae)Carangidae, and Acinaceidae (=Gempylidae).Among the crustacea, isopods, decapods, andstomatopods occurred in 10 percent or more ofthe stomachs, Koga (l958b) also examinedstomachs of albacore from the equatorial SouthPacific and found that the following were presentin 10 percent or more of the stomachs: Plagyo-dontidae, Triacanthidae, Acinaceidae, Ostra -ciidae, and Menidae. Squid were present in 50percent, decapod crustaceans in 15 percent, andoctopods in lO percent of the stomachs.

291

Iversen (MS) examined the stomachs of 544albacore captured by longlining, trolling andgill net fishing in the central and northeasternPacific. He found that there were differencesin the average volume and the composition ofthe foodstuffs in stomachs of albacore caughtby different fishing methods (Table VII andFig. 9).

Table VII

Average stomach volumes of 348 albacore,according to method of capture (Iversen, MS)

Method ofcapture

LonglineGill netTroll

Numberof

stomachs1828779

Average volume(cc)

per stomach26.7

9. 815.1

3. 4. 3 Relative and absolute growthpatterns and rates

Studies on the age and growth of albacore inthe Pacific Ocean have been made by Uno (l936a;1936b), Aikawa and Kato (1938), and Partlo (1955),based on the vertebral method.

Suda (1954) studied the size composition ofalbacore taken in the Japanesé winter longlineseason and found modès at 57 cm 67 cm,78 cm. 89 cm 100 cm and 111 cm, Thespacing of the intervals was uniformly 10 or 11cm3 thus representing a straight-line growthif these length groups are assumed to be ag&classes. Suda concluded that these lengthgroups may be considered as age groups if theyare handled as five groups consisting of ages Ito IV and an advanced age group which includesthe last two mo4al groups.

Nose, Kawatsu, and Hiyama (1957) made astudy of age and growth of albacore based on theca1e method. They found that the lengths of

albacore at the time of ring formation were asfollòws: li=38 cm, 12=49 cm,, 13=59 cm,14= 68 cm, 15= 78 cm, 16= 86 cm 17= 96 cmand 18= 105 cm.

Otsu (1960) reported on a study of age andgrowth of albacore based on data obtained fromtagging experiments. The growth rates derivedby Otsu are presented ihTb1e VIII and Fig. 10.Otsu (1960) also discussed the results obtained

FIb/ S52 Albacore 3:7

OThER FOOD

OTHERMOLLUSCS-

CRUSTACEANS

SQUID

TOTALFISH

TOTALFISH

SQUID

OTHER FOOD

OTHERMOLLUSCS

Fig. 9 Comparative importance, by volume, of major food elementsfound in 348 albacore stomachs (Iversen, MS

292

CRUSTACEANS

I MM.

Fig. 8 Thunnus germo, 6.47 mm (reproduced from Matsumoto, MS)

CRUSTACEANSOTHER FOOD

OTHER MOLLUSC

SQUID

TOTALFISH

3:8 FIb! S52 Albacore

LONGLINE TROLL GELL NET(NI82) (N79) (N87)

by the earlier workers and noted that all thecurves were linear, with the possible exceptionof Uno's (1936b) (Fig. 11), while the curves hederived were curvilinear. Although the severalgrowth rates did not differ markedly in magni-tude, Otsu points out that the linearity of thecurves obtained by the earlier workers suggeststhat the vertebral method of aging albacore isnot valid.

More recently, Clemens (1961) and Bell(1962) made albacore age and growth studiesbased on data obtained by tagging experimentsand scale reading, respectively. Both Clemensand Bell fit their data to von Bertalanffy'sgrowth equation. Their results are presentedin Table IX and Figs. 12a and 12b.

3.5 Behavior

3.5. 1 Migration and local movements(see also section 5.3. 1)

The migration of albacore within and amongthe three important fisheries in the North Paci-fic Ocean has been described in some detail byClemens (1961) and Otsu and Uchida (MS).The account of the migration among the fisheriesgiven by Otsu and Uchida is briefly summarizedbelow and is illustrated in Fig. 13.

A varying portion of the 2-, 3-, and 4-yearold fish and nearly all the older fish in theAmerican fishery migrate westward each fallinto the Japanese longline fishery. The remain-der of the fish from the American fishery move

293

westward into midocean waters of the NorthPacific, some as far west as the fringe of theJapanese longline grounds. Those that moveinto the longline fishery tend to migrate south-westward and later enter the Japanese livebaitfishery. The others will return to the Ameri-can fishery the following season. Thus, somefish may be available to the American fisheryfor as many as 4 or 5 consecutive seasons.

Albacore enter the Japanese winter fisheryfrom both the Americai fishery and theJapanese livebait fishery. Each spring, alarge portion of these fish, age groups 2 through5 years, migrate westward from the longlinegröunds into the livebait grounds, while a fewseparate and move eastward into the Americanfishery. The larger adults, 6 years old andolder, move southward from the winter long-line grounds into subtropical and tropicalwaters, to the spawning grounds of the NorthPacific albacore.

3.5.2 Schooling

In the eastern North Pacific, albacore arefound in school groups (Clemens, 1961). Aschoo] group, as defined by Clemens, is a dis-crete cluster of albacore schools that, althoughsometimes widely scattered, appear looselyrelated by having a tendency to act in unison.

Table VIIIGrowth rates of albacore derived by fittingtag recovery data to growth curves by the

methods of Walford and Riffenburgh(Otsu, 1960)

Table I X

Albacore age and growth as estimated bytagging experiments and scale reading

Agegroups

Fork length(cm)

nc r eme nt(cm)

AGE*(years)

LENGTH (cm) Clemens(1961)

Bell(1962)

Clemens(1961)

Bell(1962)Waif ord Riffenbur gh

i2

3

426. 346. 8

7. 517. 331. 546, 5

I

II

52

65

57. 3

65. 713

11

8.4

il 756789io

62. 775.184. 892. 398. 2

102.7

62. 575. 086. 094. 5

1 01. 0106 . O

Ill

IV

V

VI

76

85

93

loo

77.4

83. 7

87. 8

9

8

7

5

6. 3

4. 1

* The ages given are based on an arbitrarilyselected origin and are therefore tentative. VII 105


Fig. 10 Growth data fitted to a Gompertz equationby Riffenburgh' s short method. Thecurve obtained by Walford' s method(dashed) is superimposed. Observeddata are superimposed on the Gompertzcurve (Otsu, l960

294

Fig. 11 A comparison of the growth curves obtainedby the vertebral method with the Walfordcurve obtained in this study. Specificages are disregarded in the plotting ofthese curves (Otsu, 1960)

3:10 FIbIS52 Albacore

N+8Io

N+68

N+79

N+57

N3 N+45 6

AGE (YEARS)

N- N NI2 3

N N+I N42 N+3 N+4 N+5

AGE (YEARS)

N+6 N+7 N+8 N+9

120

loo

80

60

40

20

LI35.6 CM.

- - -

2 3 4

AGE (YEARS)

Fig. lZa Albacore weight-length-age curve based on21 ag recoveries, 1952 through 1957(Clemens, 1961)

00

87.8

60 774

60-

40-

20 /

57.3

65.7

III 3WANNULI AND AGE

295

63.7

4

Fig. lZb Albacore growth curve. The scale ofthe abscissa represents months ofthe year. The first annulus is sethypothetically at February. Theage is set at October. Theintercept at y is set at March(Bell, 1962)

GROWTH CURVEDETERMINED BYTHE SCALE METhOD

53

46


5 6 7

n 2 5W 6 32 7

Fig 13 Model of albacore migrations in the North PacificOcean, by age groups (ages encircled) (Otsuand Uchida, MS)

296

J"

.L- Y'________

I

30

20 30 um 15m ir um i8o 1iT 1Ú' 10 u4 u0 12m

ni

-

I

ri .... .,,_,-

..................

..

3

..........

/)\.. ..

LT

......

40j)

ç__"

..I1AWAII

3YAfl-OLD

um

-

13m l4Ár ism i Q iom

..i7m 16oIi0 J4 i2

I.IIAWAII

-YEA1-OLD

0 13,

f raìiy

i5 16 17 180 170 16 151P 140

'Ø/

......

,........"

$,-'---

3 - 4j 40

S.

i .

iiAWAII.

um

J

13 L40 ism io 17m ism 17m I6 15 wr 13 12Cr

i:

M2,

I

f

L'3EIS

"

40

I

ur-jimy-

HAWAII

-1Afl-OLDS

9W

3:12 FIb! S52 Albacore

FIb/S52 3:13

According to Clemens, at the beginning ofthe albacore season on the west coast of theUnited States, the school groups are widelyseparated and are composed of relatively fewsmall, scattered, loosely knit, fast-travelingschools. During the peak of the season,although the individual schools are still some-what loosely knit, they are larger. The schoolgroups appear more compact and contain agreater number of schools. Albacore largerthan 20 pounds usually are more compactlyschooled than smaller fish and spend more timein deeper water.

The schools of albacore encountered offJapan appear to be generally small, perhapspartly because of the intensity with which they

297

are harried and broken up by concentratedfleet action (Van Campen, l960)

3. 5. 3. Reproductive habits (see section3. 1)

- Physiology

It is generally assumed that tunas, includingalbacore, have high metabolic rates. Forexample, Clemens (1961) states, "Albacore arefast-traveling, opportunistic feeders, with highmetabolic rates and they need quatities of food. "However, there is very little information inthe literature on the metabolism or other facetsof the physiology of albacore.


4 POPULATION (STOCK)

4. 1 Structure

4.1.1 Sexratio

Brock (1943) analyzed the size distributionby sex of a sample of Oregon albacore takenfrom July 30 to October 14, 1940. He noted asignificant departure from a 1:1 male to femaleratio for fish smaller than 67 cn-i (Fig. 14).He attributed this to incorrect determination ofsex in a significant portion of fish smaller than67 cm. The sex ratio of albacore larger than67 cm did not differ significantly from 1:1.

Otsu and Uchida (1959a) noted that the sexratio was nearly 1:1 for a sample of albacorecaught in the central equatorial Pacific.

Table XSex ratio of albacore in the North Equatorial Current area*

*Includes the individuals whose body length was no

Table XISex ration of albacore

298

In Hawaiian waters, however, they noted thatthe males predominated (Fig. 15). Otsu andUchida (l-959b) ascribed the unbalanced sexdistribution among larger albacore largely todifferential growth which sets in with the on-set of sexual maturity, after which the malesgrow at a faster rate than the females.

Suda (1956) found that there was an extra-ordinarily high proportion of males in the NorthEquatorial Current area (western North Pacific)(Table X). Although Suda does not mention it,the size distribution of albacore by sex he pre-sents (Fig. 16) also illustrates the differentialgrowth of large albacore, as observed by Otsuand Uchida (1959b).

Other references to sex ratio of albacoreare listed in Table XI.

measured.

Date Locality Sex ratio Reference

Jan, 29-Mar. 12, 1952

Oct. 17-Nov. 28, 1952

Jan, 1959-July 1960

08°00' S - Ö8°02' N154°56' W - 179°50' E05°00' S - 21°1l' N150°39' W - 170°08' W

New Caledonia

I male:I. 32 female

1 male:1. 6 female

27, 5 percentfemales

Murphy and Shomura(1953)

Murphy and Shomura(1955)

Legand (MS)

(Suda, 1956)

Date of investigation Locality Male Female Ratio(o,I)

May 4-May 23, 1949 l8°l8' N -20°59' N 148°10'E -152 °02' E 84 40 2.1June 22-July 2, 1949 210561 N -22°56' N 148° 52' E -152°54' E 59 26 2. 3Mar. 5-Mar. 22, 1949 21°00' N -24°l3' N l43°32' E -151°45' E 14 6 2. 3Feb. 14-Feb. 19, 1950 22°12' N -24°42' N 149°52' E -l52°28' E 17 3 5. 7

Mar. 26-Apr. 6, 1950 22°50' N -24°10' N 143°15' E -146°09' E 56 9 6. 2

May 17-June 14, 1952 l3°55' N -22°54' N l46°23' E -l53°06' E 10 12 0. 8

July 2-Aug. 1, 1952 l0°08' N -24°04' N l50°23' E -158°43' E 56 16 3. 5

Total 296 112 2.64

I; i j i J I J i

102 04 106 108 110 112

FISH LENGTH (CM.)

299

fl MALESFEMALES

Fig. 15 Size and sex distribution of albacore sampled from landingsin the Hawaiian Islands, (a) 1955 (b) 1956 (Otsu and Uchida,19 59a)

55 60 65 70 75 80 85 90

LENGTH (CENTIMETERS)

Fig. 14 Length-frequency curves of males andfemales, Oregon albacore (Brock,1943)


FIb! S52 Albacore 4:3

4. 1. 2 Age composition

In conjunction with studies on age andgrowth, attempts have been made to determinethe age composition of the catches from thealbacore fisheries in the temperate NorthPacific. Uno (1963a) measured 1, 500 albacoretaken by pole-and-line fishing in the waterseast of Cape Nojima, Japan during May toJune 1935. He made age determinations on300 of these fish and found that 6 percent wereof age IV, 86 percent of age V, and 8 percentof age VI (Table XII). Based on the size dis-tribution of these age groups he estimated thatof the 1, 500 fish sampled, 4 percent were ageIV, 91 percent age V, and 5 percent age VI.Uno (1936b) sampled the same fishery the fol-lowing year, during June, and made age deter-minations on 688 albacore (Table XIII).

Table XII

Age composition of albacore (from Uno, 1936a)

300

Aikawa and Kato (1938) determined the agesof 10 large albacore taken near Midway Islandand 5 small albacore taken off northeasternJapan, and calculated the size and weightranges of albacore at different ages. Theypresent a size frequency distribution ofalbacore caught between 28° - 340 N, 170° -173° E, and suggest that the modes at 25 cm,45 cm, 56 cm, 62 cm, 74 cm, and 83 cmcorrespond respectively to age classes fromfish of the year to the sixth year (Fig. 17).

In the British Columbia albacore fishery,Prtlo (1955) points out that four size groupswere represented in the catches. during 1949,1950 and 1951. The average lengths of thesesize groups were 54.3, 62.9, 71,7 and 81.9cm and the corresponding ages were III, IV,V and VI (Table XIV and Fig. 18).

Date landedNumberlanded Age IV

Numberdeterrrdnations

of

Age V

ageAge compositipn (%)

Age VITotals Age IV Age V Age VI

(1) V. 1 V.19 15, 500 4 35 40 10 87 3

(2) V.20 VI. 2 89, 863 3 67 2 72 4 93 3

(3) VI. 3 VI. 10 62, 355 8 42 0 50 16 84

(4) VI.11 VI. 17 21, 555 0 65 5 70 93 7

(5) VI.18 VI, 30 13, 344 2 51 15 68 3 75 22

202, 617 17 260 23 300 86 8

p

- FEMALE(N..ÌII)

MALE(N29I)

o20 30 40 50 60 70


o u inAGE CLASSES

Fig. 17 Age composition of a sample of albacore caughtbetween 28°-34° N., 1700_1730 E. (Aikawaand Kato, 1938)


Fig. 16 Length frequency of males andfemales caught in the NorthEquatorial Current Area(Suda, 1956)

50

40

30

w

z20

301


60 90 loo

5

Io

o

5

o-


Fig. 18 Comparison of length frequency distributionof the 1949, 1950 and 1951 BritishColumbia albacore catches (Partlo, 1955)

302

1949N. 38,418)

1950(N '29,474)

1951(N' (0,524)


60 70 60

Table XIIIAge composition of albacore (from Uno, 1936b)

Agegroup

Body length(cm)

Body weight(kg)

303

Body length (cm Body weight (kg)

Age IV AeV Age VI Age IV AgeM

VS D,

AgeM

VISDM SD M ,5 D M SD M SD

(1) 72, 70 0.73 79. 32 4.22 88. 00 2 8.075 1. 546 9. 924 2. 040 14.150 2(2) 72, 50 1. 81 78. 80 2.81 88. 30 0.50 7.950 0. 071 9 .496 1. 040 12.925 0,177(3) 72.06 1.26 79. 25 3. 32 8 287 0,415 9. 260 0. 750(4) 80. 21 3.42 88.40 0. 92 11. 049 1. 340 13 .720 0, 352(5) 73. 35 0.84 81, 57 3.84 90,22 2.49 7,-575 0.079 10.488 1. 670 13.276 1. 800

72. 38 1, 30 79.15 3.68 89.55 2.25 8.094 0. 824 10.149 1. 520 13. 380 1.490

Date landed Totals.Age IV Age V Age VI Age IV Age V Age VI

VI.1 -VI.9 69 252 44 365 18. 9 69. 0 12, 1VI.10- VI.15 23 111 18 152 15. 2 73. 0 11.8VI.l6- VI.20 21 119 31 171 12. 3 69. 6 18.1

Totals 11 3 482 93 688 15. 5 70. 5 14.0

M SD M SDIV 69. 04 4.65 7. 607 0.815V 81.56 3.82 11. 774 1. 670

VI 89. 70 1.98 15. 192 0.948


Number of agedeterminations Age composition (%)

FIb/S52 Albacore 4.7

All the studies listed above were based ondetermining the age of albacore by reading markson the vertebrae. There is some doubt aboutvalidity of that method, for Otsu and Uchida(1959b) found that they could not satisfactorilyduplicate the results Ôf the earlier workers.

However, size frequency analyses of alba-core catches in the temperate North Pacific haveindicated that the various size groups appearingin the fisheries can be regarded as year-classes(Brock, 1943; Suda 1954). Furthermore, growthdata obtained from tagging experiments have cor-roborated these observations (Otsu, 1960;Clemens, 1961).

Otsu and Uchida (MS) and Uchida and Otsu(MS) have estimated the ages of the differentsize groups occurring in the various fisheries,based on growth data derived from tagging experi-ments and other information (Fig. 19). An esti-mate of the percentage composition, by number,of each age group occurring in the albacorefisheries in the Pacific Ocean is found in TableXVI.

Table XIV

Percentage composition, mean length, standard deviation, standard error of the mean, andavailability (fish per boat-hour fished) of component size-groups of the 1949, 1950, and 1951British Columbia Albacore Catches. Total availability estimates for each year are included

(Partlo, 1955)

3014

Bell (MS) gives the age composition of thealbacore catch during September -November 1959in California (Table XV). It should be pointedout that there is a discrepancy of one year be-tween the age estimates made by Bell and Otsuand Uchida (MS). Therefore, although it isgenerally agreed that the size groups of albacoreare year-classes, there is still no agreement onthe absolute ages of these year-classes.

4. 1. 3 Size composition

The size composition of the catches of alba-core in the various fisheries in the Pacific Oceanis well documented. In general, each fishery isdependent on certain characteristic size groups,which appear rather regularly each year.Uchida and Otsu (MS) summarized published andsome unpublished' data on albacore size frequencydistributions into composite size frequency distri-butions for the fisheries in the Pacific Ocean(see Fig. 19).

Mimura (1957) has reported on the size com-position of the catches of albacore in the IndianOcean (Figs. 20a and b).

YearTotal

availabilitySize

groupPercentage

compositionMe a n

length(cm)

SD SE Availability

1949 5.04 A 3. 05 53.25 1. 35 0. 040 0.15B 28. 95 63, 30 2.07 0. 020 1. 46C 65, 50 71, 10 2.82 0. 0 18 3. 30D 2. 50 82, 95 2.87 0. 093 0. 13

1950 3. 39 A 0,40 54.27 1. 75 0. 160 0.01B 11. 90 62.35 2.05 0. 030 0.40C 80. 70 7 1. 35 2. 62 0. 0 17 2.74D 7. 00 79. 70 2. 37 0,05 0.24

1951 2.19 3.50 55. 25 1.65 0.086 0. 0881. 50 62.90 2.75 0.029 1. 78

C 13. 10 72. 75 2,75 0.074 0.29D 1. 90 82, 95 3.02 0,214 0.04

o

IO

5

Io

5

0

IO

5

IO

5

0

5

'JA

JAPANESE

/ //

/

NINTER LONGLINE(948-5)N54,653)

ANESE1950-51,56

(N 14,462)

HAWAI

2

SPRING LIVEBAIT

N LONGLINE149,55-57(N392)

HILE

N'565)

INE

47 63 75 85 92 98LENGTH IN CENT81ETER'S

I I I3 4 5 678910PROBABLE AGE IN YEARS

305

103 J 9I IUb*

Fig. 19 Combined length frequency distributionseparated into component age groupsusing growth rates derived by Otsu(1960) (Uchida and Otsu, MS)

AAh.

FIb/S5 Albacore

5

lo

S

U.S.1949-5G,

WEST

(N 21,007)56-58COAST

s,

g

IO

JAPANESE S. PACIFIC LONG- 1956-57(N 2,791)

1-zwC,

wo-

flÁ

A

N 487

N47I

N455

NIO2_

N558_

20

I0

20

Io

o

I0

20

Io

20

lo

o 90 lOO 110 20


Fig. ¿Oa Length frequency of albacoreby month, caught in theSouth Equatorial CurrentArea (9°-25° S, 9O0.120° E ) (Mimura, 1957)

30

pIur%1911i

306

N98

1'Ib/S5 Albacore 4:9

o lOO bIO 20


Fig. ¿Ob Length frequency of albacore,caught in the EquatorialArea, (a) O°-3° N, 1955,Apr. Jun., (b) O°-4° S,1955, Apr. (Mii-nura, 1957)

20 A

IowC,

o-

BIo -

Table XV

The age composition of the catch - September, October, November 1959(adapted from Bell, MS)

307

Fork length(cm,)

Number of fish, by age, in the catchII III IV V

4451Si

233466

2,33153 3,330 1,33254 6993 1,16555 16,08156 11,012 3,67157 17,196 2,14958 11,071 2,21459 11,265 3,25360 13,285 4,42861 9,012 18,02462 5,461 32,76263 10,848 48, 31764 15,344 76,71765 108, 84266 20,714 89,75967 10,365 62,187 10,365 5, 18268 48,925 4,44769 17,784 11, 11670 8,823 3,52971 5,827 2,33172 1,199 2,99673 4,42974 599 2,997 59975 5,36076 1,166 3,49677 4,661 93278 1,099 4,395 2,19779 1, 224 6,118 2,44780 3,088 7,720 1, 54481 7, 738 11, 60782 9,230 1 3,84483 7,924 11,88784 2,823 2,823 19,75985 2,963 14,8 17 2,96386 3,329 4,995 3,32987 1,398 4,195 2,09888 1,010 4, 040 1,01089 1,332 333 66690 1,048 35091 23392 233 23393 23394 23395 2339697 23398 233

Total s 165,007 543,789 107,075 106,068 13,358


Table XV1

Percentage composition, by number of each age group occurring in thecatches of the albacore fisheries in the Pacific (Uchida and Otsu, MS)

No one, insofar as is known, has attemptedto make estimates of the size of the albacore popu-lations in the Pacific or Indian Oceans.

4. 2.2 Changes in size

Otsu (1959) surveyed the fisheries of the NorthPacific for the period 1930-1957 and made a fewobservations on their condition. Although he didnot give absolute numbers, he stated thatseems unlikely that the exploitation has seriouslyaffected the albacore stock" and "there is no indi-cation of a declining resource.

4. 3 Natality and recruitment (see section4.5)

4. 4 Mortality, morbidity

4.4.1 Rates of mortality

Tauchi (1940), on the basis of the size compo-sition of albacore catches during 1934-1937 inJapan, estimated that the survival rate was . 66,the fishing rate about . 18, and the natural morta-lity rate . 20.

4. 5 Dynamics of population

Suda (1958) made a study of the "interchange"of albacore in the Japanese North Pacific fisherias.He defines 'interchange' as the recruitment anddispersion of albacore into the exploited population.Suda found that the interchange of albacore in theNorth Pacific fishing grounds takes place once a

308

In a later report Suda (1959) examined therecruitment phase of the interchange in greaterdetail. Suda calculated an index S, which is anestimate of the magnitude of recruitment of ayear class into the fishing ground. This indexwas calculated from data obtained from the long-line fishery. Suda also calculated an index C,which is an estimate of the total number of alba-core caught by both the longline and livebaitfisheries. He found that although there is somerelationship in the relative magnitude of index Sand C, index C does not agree perfectly withindex S. He also found that the yearly variationin recruitment was very large; that after a cer-tain level of index S was attained, it tended to bemaintained for several years; that there was atendency for a clear biennial variation during aperiod of generally high level of recruitment,which become obscure during periods of low re-cruitment; that there was no definite relationbetween the size of the spawning grou and thesize of the recruitment.

4. 6 Relation of population to communityand ecosystem, biological production etc.

From his study of the recruitment of albacorein the Japanese North Pacific fisheries, Suda(1959) concluded that there seem to be variationsin the basic productive potentials of the sea areainhabited by albacore larvae. He based thisconclusion partly on the observation that after acertain magnitude of rcruitment was attained,this magnitude tended to be maintained for seve-ral years and that the size of the spawning groupwas not related to the size of recruitment.

Age(years)

North Pacific South Pacific

UnitedStates

Japane sewinter

longline

Japane sespring

livebait

Japanese]hngline00 - 30° S

Chile

1 <0.1 1.02 17. 6 2.1 <0,1 5. 73 70, 8 1 6.2 5. 5 0. 1 76. 14 11.4 35,6 50.4 5. 9 15.45 0. 2 24. 7 37. 2 22. 2 1. 76 9. 5 5. 7 41. 7 0. 97 4. 7 0. 2 Z4. 8 0. 28 3. 1 <0. 1 4. 09 2.2 1. 3

lo 1. 9 0. 1

4. 2 Size and density year around March and that the fishing conditionof the following year is greatly influenced by this

4. 2. 1 Average size. interchange.


FIb/S52 Albacore 5 i5 EXPLOITATION

5. 1 Fishing equipment

5.1.1 Fishing gear

The U.S. west coast fishery takes albacoreby trolling and livebait fishing. The trollinggear consists of a 20- to 30-foot pole, usuallyeucalyptu.s, rigged on each side of the boat, towhich several lines with fishing lures are attach-ed A detailed description of the trolling gearis given by Scofield (1956).

The gear used in the livebait fishing methodconsists of a bamboo pole with a barbiess hookat tlie end of a 6-foot line. The pole averagesbetween 8 and 9 feet in length, varying accord-ing to the size of the fish being caught and thepreference of the fishermen. The gear andfishing method are essentially similar to thatdescribed by Godsil (1938) for the yellowfin andskipjack livebait fishery in the eastern Pacific.

In general, the fishing gear used in theJapanese livebait fishery for albacore issimilar to that used on the U. S. west coast.A detailed description of the gear and fishingmethods is given by Cleaver and Shimada (1950).

Longline gear is used in the Japanese winterfishery, the fishery based at Samoa and the NewHebrides in the South Pacific, the fishery in theIndian Ocean, and the Hawaiian fishery. Thegear probably differs only in minor details inthe various fisheries. The following excerptdescribing longline gear is taken from Shimada(1951).

"The basic unit of longline fishing gear isthe A basket consists of severalsections of main or trunk line, usually cotton,to which are tied a number of branch lines anda float line (Fig. 21). Each branch line is madeup of a length of cotton line; or a sekiyama? or'shanawa' (cotton thread wound around a core ofwire or fiber); a wire leader and hook. Lines,including the 'sekiyama', are coated with tar toprevent deterioration and to add rigidity for easeof handling.

"The baskets are tied in one continuous linewhen a set is made. Glass or metal floats,varying in diameter from 10 to 12 inches, areused to buoy the main and branch lines at sub-surface level,"

309

5.1.2 Fishing boats

In the U.S. west coast fishery there appa-rently are no boats that may be called "typical"albacore livebait or trolling boats. Accordingto Clemens (1955), the fishery comprisesvessels of myriad sizes, shapes, and descrip-tions using two types of gear, livebait andtrolling. The smaller boats usually under 30feet in length, catch fish by trolling, while thelarger boats, usually over 30 feet in length,are equipped for livebait fishing (Fig. 22).

The following, taken from Van Campen (1960),is a brief description of the type of boat used inthe Japanese livebait fishery.

"The most conspicuous characteristics ofthese craft are the long, high bowsprit bearingprolongations of the fishing racks, the racksextending along one or both sides of the vesseland around the stern, only about 1 foot below thehigh gunwale, and the spray-system pipes, withclosely spaced nozzles, paralleling the racks.The superstructure is all abaft the beam, andthe long open welldeck has 9 or 12 hatches. Thosehatches along the sides lead to the iced fish holdsand those along the midline open into the livewells, Pump circulation for bait wells has notyet caught on in Japan, and the practice of cir-culating the water through simple openings inthe vessel's bottom is almost universal inJapanese bait boats. Most of the boats of lessthan 130 tons gross are of wooden construction;all of the larger ships are steel." (Fig. 23).

"The typical Japanese longline vessel resem-bles an Atlantic well-deck trawler and is char-acterized by a strong shear line (Fig. 24). Poweris usually supplied by a Diesel engine and, inmany cases, auxiliary gaff-rigged sails are alsocarried to supplement the main engine. Thewheelhouse is located amidships and the engineroom is aft. This setup provides ample work-ing space forward, which is free of excess deckstructures, except for the longline hauler whichmay be situated on the port or starboard side.Often, two longline haulers are so installed thatfishing gear may be taken in from either side.Removable doors are cut into the bulwark forbringing fish and gear aboard.T' (Shimada, 1951).

Otsu (1954) gives a description of the boatsused in the Hawaiian longline fishery. Briefly,the boats are built along the lines of the Jap-anese sampan-type livebait boats, with a high

and narrow bow, a modified V-bottom, and amoderately iow freeboard aft. The afterdeckhas sufficient space for handling the fishing gearefficiently. The boats range in size from 40 to63 feet in over-all length, with about a 12-footbeam and a 6 foot draft on 60-foot boats. Theyare powered with a Diesel' main engine of 115 to165 horsepower, usually of the high-speed type,driving a single screw through a reduction gear(Fig. 25).

In Chile, the albacore fishing boats aregenerally 7. 20 meters long, 0. 62 meters deep,with a beam of 1.50 meters, and are calledlbongosu. Power is supplied by outboard

motors (de Buen, 1958).

5.2 Fishing areas

5. 2. 1 General geographic distribution

The general localities of the major Pacificand Indian Ocean albacore fisheries are shownin Fig. 26a and 26b.

5. 2. 2 Geographical ranges (latitudes,distances from coast, etc.)

Clemens (1961), in speaking of albacore says,'TIn the eastern North Pacific individuals havebeen recorded off Mexicots mainland at ClarionIsland, of the Revilla Gigedo Islands group, andnorthward along coastal Baja California, Cali-fornia, Oregon, Washington, British Columbia,and in 'the Gulf of Alaska. The most productivefishing grounds, however, lie between centralBaja California and the Columbia River.

The fishing grounds of the Japanese livebaitalbacore fishery are in the form of an arc avera-ging about 200 to 300 miles in breadth and exten-ding from around 30° N, 140° E to 32° - 330 N,160° - 165° E. The extreme western end of thegrounds is within 100 miles of port and the ex-treme eastern end is over 1, 000 miles away(Van Campen, 1960).

The longline fishing grounds for albacore inthe South Pacific extend from about 100 N to 30°Slatitude and from about 140° W to 1600 E longi-tude. This area is fished by Japanese and a fewKorean longliners operating out of Samoa and theNew Hebrides, Japanese longline boats whichoperate in mothership fleets, and independentlyoperating longliners (Otsu, 1959).

310

In the Indian Ocean there are two longlinefishing grounds for albacore. One is locatedbetween 5° N and 5° S latitude, stretching fromabout 500 E to 1000 E longitude. The other ex-tends from about 8° S to 250 S latitude and from500 E to 120° E longitude (Min-ìura, 1957).

In the Pacific Ocean, other localities wherealbacore are exploited commercially are thewaters off Chile, Australia and around theHawaiian Islands. However, the landings ofthese fisheries constitute only a small portionof the total albacore landings in the PacificOcean.

In the Chilean fishery, the area of largestcatches covers central Chile, in the provincesof Aconcagua and Valparaiso, and exceptionallyalbacore may be taken off Taltal, and to thesouth as far as Talcahuano (de Buen, 1958).This fishery is conducted within 15 miles ofthe coast (Manning, undated report).

The longline fishery in Hawaii, which takesalbacore only incidentally with other morenumerous species of tunas and spearfishes, isconfined to within 20 miles of the island (Otsu,1954).

In Australia, albacore are taken on the south-eastern coast from Port Macquarie in New SouthWales on the north to Westernport in Victoria onthe south. It is also caught on the east and southcoast of Tasmania and on the south coast ofwestern Australia (Roughly, 1951).

5. 2. 3 Depth ranges

Albacore are caught at the surface by trol-ling or livebait fishing on the U. S. west coast,and in the Japanese livebait, the Chilean andthe Australian fisheries.

Deep-swimming albacore are caught bylongline gear in the Japanese winter fishery inthe North Pacific, in the Indian Ocean fishery,the fishery in the South Pacific, and around theHawaiian Islands. Although longline gear fishessubsurface levels, the absolute depths fished bythe gear has not been reliably determined.However, it has been shown that in the centralequatorial Pacific, albacore are generallycaught in greater numbers on the relativelydeeper fishing hooks of the longlines (e. g.,Murphy and Shomura, 1953).

FIb/S52 Albacore5,

s'

.---FLOAILII'E

SLASS FLOAT

ABAMBOO POLE

FEAS OFBASKET

BRA ACHLINE

SWIVEL

-.-SEKlYAMA

WIRELEASER

EIOOV

MAIN UNE/

ONE BASKET

TALBASKET

Fig. ¿1 Diagram showing the component parts of abasket of tuna lorigline fishing gear(Shimada, 1951)

Fig. ZZ U. S. west coast albacore boats (photograph courtesy of Harold B.Clemens, California Department of Fish and Game)

311


FIb/S52 Albacore

313

Fig. 25 Hawaiian longline fishing boat

¡I

--

j

5:5

FIb/S52 Albacore

Fig. 26a General localities of the major P3cific albacore fisheries(Otsu, 1959)

Fig. 26b Fishing grounds of albacore in the Indian Ocean (Mimura, 1957)

314

ASIA

p.

F

--

UNITED STATES

44Ck"

:

f180°

AUS.TRALIA1600 170° ro° 60° 50° 40° IQ° 20° 110° 00° 90°

FIt'1S52 Albacore

Shomura and Otsu (1956) reported on explora-tory ongline fishing for albacore in the centralNorth Pacific. The albacore catches by relativedepths oI capture showed that, in general, alba-core were caught in equal numbers throughout therange of fishing depths, a different situation fromthat of the central equatorial Pacific. Shomuraand Otsu suggested that the difference in the vertical distribution of the North Pacific albacoreand equatorial albacore may be associated withthe difference in water temperatures, between thetwo areas, The water temperatures which occurat the surface in the North Pacific are found indeeper la.yers near the Equator.

5. 3 Fishing seasons

5.3.1 General pattern of fishing season

The Japanese livebait fishery begins offsouthern Japan. gradually moves north andnortheast, and ends far offshore at about 160° Elongitude (Van Campen, 1960).

The Japanese longline fishery begins in mid-ocean generally between 170° E and the 180thmeridian and along 38° N latitude. There is agradual southwestward shift of the areas ofhighest catch rates. Towards the end of thefishing season the center of concentration shiftsto around 30° N latitude, 140° E longitude(Nakamura, 195:!; Suda, 1954).

The American fishery tends to move north-ward up the coast and off-shore as the seasonprogresses (Clemens, 1955).

5.. 3, 2 Duration of fishing season (Seesection 5. 3. 3)

5, 3. 3 Dates of beginning, peak, andend of season

In the United States west coast albacorefishery, typically, the fishery buds in June,develops very rapidly in July, is in full bloomby August and September, wanes duHrig Octoberarid November, and finally dies in December,.In exceptionalyears fish are caught from Maythrough January (Clemens, 1955).

The normal seasonal pattern of developmentof the Japanese summer fishery for albacore isfor sporadic catches of small numbers of fishto begin in March and continue through much ofApril. Sometime between the latter part of

315

5:7

April and the end of May the first large catchesare made. By the middle of June the landingsrise steeply to their peak of the season. In Julythe landings decline rapidly and by the end ofJuly the season is virtually over (Van Campen,1960).

The Japanese winter longline fishery isconducted between November and April over abroad area of the North Pacific. The seasonreaches a peak, in general, between Decemberand February (Suda, 1954).

Albacore are caught throughout the year inthe South Pacific longline fishery. There is noclear seasonal variation in landings, but themore productive months appear to be fromAugust through February (Otsu, 1959).

In the Indian Ocean, the fishing season ex-tends from April to September in the albacorefishing grounds straddling th Equator. On thegrounds south of 8°S latitude, albacore arefished throughout the year. The catch rates hereare higher during April through September thanduring the rest of the year (Mirnura, 1957).

5. 3. 4 Variation in time or duration offishing season

Apparently during certain years sorne alba-core remain along the United States west coastover the winter. According to Clemens (1961),,during the winter of 1955-56 a few albacore werecaught in December, January, and early Febzu-,ary.. During the winter of 1956-57 sorne weretaken from December through April; and in 1957-58 albacore were caught in December, January,February, March, and May.

The seasonal patterns of the Japanese live-bait and longline fisheries described in thesections above are overly simplified versionsof a more complex picture. Van Campen (1960)pointed out that while Japanese writers oftenimply that all pole-and-line fishing is done inthe spring and summer and all longlining ìnwinter, some albacore are taken by both methodsin all months of the year.

5. 3. 5 Factors affecting fishing season

Clemens (1961) discusses in sorne detail themovements of albacore in relation to surfacewater temperatures off the United States westcoast, which has an effect on the fishing season.

58 FIb/S52 Albacore

He points out that there is a definite albacorecatch-temperature relationship in the easternNorth Pacific. In the past a majority of the alba-core has been caught while traveling within thenarrow temperature range of 600 - 670 F. Thedevelopment of these surface water temperaturesseems to play a part in the movement of albacorealong the coast, .which in turn affects the develop-ment of the fishery.

In Japan also the way in which the pattern ofsurface temperature distribution develops isthought to affect the summer albacore fishingseason. It is believed that the manner in whichthe warm Kuroshio pushes northward, resultingin isolated masses of water with suitable tem-peratures close to the coast of Japan, favorssuccessful fishing (Van Campen, 1960). Accord-ing to Sasaki (1939) albacore are taken in watersranging from 18° to 24° C in temperature andthe range of favorable temperatures is 190 to23° C,

5.4 Fishing operations and results

5. 4. 1 Effort and intensity

Otsu (1960) made a survey of the Americanand Japanese albacore fisheries in the Pacificand noted that "it has not been possible tocompile satisfactory statistics on fishing effortto be examined in relation to gross landingsstatistics, " However, he noted that followingSecond World War the Japanese have continued toenlarge their fishing fleets, and have builtlarger vessels capable of fishing more distantwater. Table XV II, taken from Johnson (1959),illustrates the growth of the Japanese tuna fleet.

Table XVII

Increase in size of Japanese Tuna Fleet,

316

Clemens (1961), speaking of the United Stateswest coast albacore fishery noted that, "althoughthe size of the commercial fleet has declinedsince 1950, well over 1, 000 vessels fished foralbacore during the 1950 to 1959 seasons inclu-sive.

5.4.2 Selectivity

Brock (1959b) presents typical examples ofalbacore sizes taken by the different types ofgear (Fig. 27).

5.4. 3 Catches

Japan is by far the world's greatest producerof albacore tuna. Since 1952 the Japanese annuallandings of this species have been from two tothree times as large as those of the UnitedStates, the second largest producing nation(Van Campen, 1960).

Table XVIII, taken from Uchida and Otsu(MS) gives the annual landings of albacore bythe various Pacific albacore fisheries fdr theperiod 1950-1959.

The annual landings of the Indian Oceanlongline fishery for albacore during the period1952-1957 are presented in Fig. 28.

5. 5 Fisheries management and regulations

Reproduced below from Clemens (no date)is a brief historical review of regulationsconcerning albacore in the State of California.

1909 - A commercial fishing license wasrequired for the taking of albacorefor profit.

1913 A sport angling license was requiredfor taking albacore for sport.

1933 - Albacore may be taken at any timeof the year. A weight limit in someform has been in effect since l915-First weight limit imposed.A brief history follows:

1, 1915-1933 - No albacore lessthan 6 pounds may be bought,sold, or offered for sale; andno more than 50 pounds may bepossessed.

1947-56. (Johnson, 1959)

Year Vessels Grosstonnage

Ave r agegross tonnage

1947 1, 314 78, 517 601948 1, 811 101, 008 56

.1949 1,893 106,897 561950 1,895 108,753 571951 1, 698 103, 978 611952 1, 590 108, 319 681953 1, 672 124, 132 741954 1, 801 154, 133 861955 1,825 176,243 971956 1,772 197,760 112

F-Ib/S52 A1baccre

Year Stateswest coast

Winterlon.line

1933-1935 - No albacore weigh-ing less than 9 pounds may besold.

1955-1957 - No albacore weigh-ing less than 7 pounds may besold.

4, 1957 to present - No albacoreweighing less than 7 pounds maybe sold, purchased, or proces-sed,

Table XVIIIAnnual landings of albacore by the various Pacific albacore

fisheries 1950- 1959 (in tons) (tichida and Otsu, MS)

apanSpringliyebai

317

SouthPacific

Hawaii Chile

1935 - A law prohibiting the use of spearsto take albacore was passed.

1939 - A bag limit on albacore taken byauthority of an angling license waspassed. The holder of a commer-cial fishing license, while on aboat carrying sport fishermen forhire is subject to the saine limit.

1950 36, ¿07 18, 423 14, 179 48 30 2711951 17, 245 12, 549 15, 984 137 28 4081952 26, 278 19, 401 46, 109 79 52 4961953 17, 417 20, 522 36, 301 320 25 7351954 13 , 499 26,145 30, 950 4,190 14 3161955 14, 866 .17, 842 26, 724 8, 637 10 7091956 20, 669 17, 396 47, 205 7, 850 7 8921957 23, 329 20, 335 54, 582 9, 643 5 4851958 19, 222 26, 472 24, 437 15, 775 8 142

1959 23, 142 35, 979 15, 706 19, 328 6 13

5 10 ELbLS&2 -AJb.a.c.cLr.e.

O

5

IO

IO

I-.zo 510wn-

O

IO

s

o

5

I I I I I I I I

GILL NETCENTRAL N. PACIFIC

SUMMER

TROLLINGU.S. WEST COAST

FALL

LONGLINEN. PACIFICWINTER

LONGLINETROPICAL S. PACIFIC- ALL SEASONS

020 30 40 50 60 70 80

LENGTH I CENTIMETERS)

Fig. 27 Albacore sizes taken by various kinds offishing gear (Brock, 1959b)

1952 1953 954

318

955 195G 1957

Fig. 28 Annual landings of albacore by theIndian Ocean lorigline fishery,1952-57 (Johnson, 1959)

5

LIVE BAITJAPAN- SUMMER

ISOIO50 lOo

synopsis of biological data on albacore thunnus … synopsis no, 9 fao fisheries biology synopsis...

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