ARCHIVES, AND MARINE SERVICE • Translation Series No. 3556

Studies on the life history of the , Xiphias gladius Linnaeus

by Hiroshi Yabe, Shoji Ueyanagi, Shoji Kikawa, and Hisaya Watanabe

Original title: Mekaj-ki (Xiphias gladius L.) no Seikatsushi no Kenkyu

From: Nankai-Ku Suisan Kenkyusho Hokoku (10): 106-151, 1959

Translated by the Translation Bureau(cEp) Multilingual Services Division Department of the Secre..ary of State of Canada

Department of the Environment Fisheries and Marine Service Biological Station St. Andrews, N.B.

1975

• . 103 pages typescript ee THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT DEPARTMENT OF RI% ine, TRANSLATION BUREAU BUREAU DES TRADUCTIONS

MULTILINGUAL SERVICES 1,e DIVISION DES SERVICES CANADA DIVISION MULTILINGUES

TRANSLATED FROM — TRADUCTION DE INTO - EN Japanese EngliSh

AuTHOR..-: AUT -E-L7R Hiroshi Iabe, shoji.Ueyanagi, Shoji Kikawa, and Hisaya Watanabe

TITLE IN ENGLISH — TITRE ANGLAIS studies on the life history of the swordfish, Xiphias gladius LINNAEUS

TITLE IN FOREIGN LANGUAGE (TRANSLITERATE FOREIGN CHARACTERS) TITRE EN LANGUE ÉTRANGÉRE (TRANSCRIRE EN CARACTÈRES ROMAINS)

Mekajiki (Xiphias gladius L.) no Seikatsushi no Kenkyu

REFERENCE IN FOREIGN LANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHARACTERS, RÉFÉRENCE EN LANGUE ÉTRAN.:2RE (NOM DU LIVRE OU PUBLICATION), AU COMPLET, TRANSCRIRE EN CARACTÈRES ROMAINS. Nankaiku Suisan Kenkyusho Hokoku,Dai 10-go Betsusatsu,

TERENCE IN ENGLISH — RÉFÉRENCE EN ANGLAIS • Report of Nankai Regional Fisheries Research Laboratory no. 10,1959.

PUBLISHER— ÉDITEUR PAGE NUMBERS IN ORIGINAL DATE OF PUBLICATION NUMeROS DES PAGES DANS The Nankai Eegional fl.sheries Researc DATE DE PUBLICATION L'ORIGINAL Laboratory, Japan. 45 (1 06- 15 1) YEAR ISSUE NO. VOLUME PLACE OF PUBLICATION ANNeE NUMÉRO NUMBER OF TYPED PAGES LIEU DE PUBLICATION NOMBRE DE PAGES DACTYLOGRAPHIÉES sanbashidori, Kochi, Japan. • 959 10 103

REQUESTING DEPARTMENT Environment TRANSLATION BUREAU NO. 1101016 MINISTRE-CLIENT NOTRE DOSSIER NCI

BRANCH OR DIVISION Fisheries Service TRANSLATOR (INITIA LS) DIRECTION OU DIVISION TRADUCTEUR (INITIALES) C -ET

PERSON REQUESTING Allan T. Reid DEMANDÉ PAR OCT - 7 1975

YOUR NUMBER VOTRE DOSSIER N°

IMEDITED TRA!'1:11.à..TiO 4 DATE OF REQUEST 10-37-75 For DATE DE LA DEMANDE intorma;fon only TRADUCTION NON REVLSEE Infonnalion sQuiernent

sos.200.10.6 (REV. 2/88) 7030-21-02Q-5333

-2) )

DEPARTMENT OF THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT TRANSLATION BUREAU eMa- BUREAU DES TRADUCTIONS

MULTILINGUAL SERVICES DIVISION DES SERVICES • DIVISION CANADA • MULTILINGUES

CITY CLIENTS NO. DEPARTMENT DIVISION/BRANCH VILLE N° DU CLIENT MINISTÉRE DIVISION/DIRECTION

Environment Fisheries Service •OttL.. wa l Ont. BUREAU NO. LANGUAGE TRANSLATOR (INITIALS) N° DU BUREAU LANGUE TRADUCTEUR (INITIALES) OCT - 7 1975 1101016 Japanese CEP " STUDIES ON THE LIFE HISTORY OF THE SWORDFISH, X1PHIAS GLADIUS LINNAEUS" * by Hiroshi Yabe, Shoji Ueyanagi, Shoji Kikawa, and Hisaya Watanabe. (The Nankai Regional Yisheries Research Lab.) CONTENTS Introduction • 1 I Outline of grounds for swordfish in the Northern Pacific ucean.. 2 II Matured eggs and larval stage 4 a. Eggs of mature ovaries b. Materials of larval swordfish c. Morphology d. Season of appearance e. Swimming depth f. Foot:. habits III Morphology of young swordfish 23 IV Morphological change with growth 36 1110 a. Morphology of the head part b. Morphology of the fins c. Colour, spots, lateral line and scales d. Viscera ' Spawning 53 • a. Situations of sample collecting from spawning area b. Egg-diameter distribution of mature ovary eggs c. Relationship between body length and ovary weight d. Distribution of matured and young swordfish e. Spawning season VI Growth 61+ a. Growth of young swordfish b. Growth curve VII Food habits 72 VIII Summary 74 IX References 76 X Appendix 98

* Nankaiku Suisan Kenkyusho Gyoseki- No. 129 (The Records of the Project Activities, the Southern Fisheries Research. Laboratory, the 129th issue)

IJNEDITL'D reIANSLATION For inform:Ilion only TRADUCTION NON REVISEE Information seulement

505-200-I 0-31 • 1 a»

INTRODUCTION 108

Many studies on the life-history of the swordfish have been reported. Some of them were reported quite a long time ago. Recently, Arata (1954) 1) reported on details of the external morphology of the larval swordfish, particularly, in the early growth period as well as the morphological changes that occurred with the growth of the inhabiting the Atlantic Ocean. Taning (1955) 21) reported.asummary, from existing literature, covering the season for spawning, distribution of the larval swordfish, environment for growth, food-habits, etc with regard to swordfish inhabiting the Indian, Atlantic, and Pacific Oceans; in addition he reported information on sample materials collected by the boat 'Dona' and others. The authors 14) 3) in 1951 reported the morphology and life of larval and very young grown in the area of the Western Pacific Ocean which is located relatively close to Japan. Since then, a great amount of information concerning the overall life-history from larval stage to adult swordfish inhabiting the wide region of the South-Western Pacific Ocean has been accumulated, while the Japanese projects on has also progressed. As a result, the fishing area has been gradually enlarged. Therefore, this paper relates this information by putting together the biologic — facts in order to contribute to the elucidation of resources supplement mechanisms. 2

Materials used for this study were provided by the Ministry of Fisheries, Provincial Fishery Research Stations, Fishery High Schools, and many fishing boats; the results of Resources Investigations which were carried out several times by the Southern Regional Fishery Research Station during the period of 1947-1958 were also available. The authors wish to express their sincere thanks to the following persons: Dr. Hirusato Nakamura, Director of the Southern Regional Fishery Research Station, for his kind instruction; the crew 4D1 the Toshitaka-Maru, the research , for their efforts in collecting materials; the Colleagues at the Division of Far-Ocean Resources at the Southern Regional Fishery Research Station for their • useful advice during discussions; and Mr. Sukeo Takahashi, the captain of the 12th Taiyo-maru fishing boat for his kind donation of many valuable source materials during our long investigation period. Many thanks are also due to Mr. Hideo Kamida, a student of the Department of Fishery Science at Tokyo University, for his work in measuring the size of samples, and to Mrs. Sumiko Nakazawa and Natsuko Yamazaki at our Fishery Research Station for their skills in the arranging of materials and the drawing of figures.

I. Outline of fishing grounds for swordfish in the Northern Pacific Ocean. Swordfish may be distributed from temperate to tropical zones all over the world. However, the fishing grounds presently • established are located only in the temperate zone. 3

•• • The region of the Northern Pacific Ocean includes the areas of the coast of the Japan Sea from Sanriku-Oki to the Izu-Retto area), the coast of Cheju Island (Korea); and the coast of California. In terms of number of used and the amount of fish caught, the largest fishing ground 109 would be the one located on the coast of the Japan Sea in the Northern Pacific Ocean. However, ships fishing for 0 swordfish have sailed in the eastern region to 160 E .

1954, and have found that the seasonal southward movement of swordfish thereby the area of 160o - 180 0E.has been developed as a fishing ground in the region of the Central Pacific Ocean. On the other hand, the fishirig boats for swordfish have not • been employed in the Eastern region of the Pacific Ocean; this area may not be considered as good a fishing ground for swordfish, although tuna fishing is ordinarily performed in this area and the catch is often mixed with white marlin and short-nosed spearfish.

A type of fishing to enhance fishing efficiency on the basis of the habitual behavior of the swordfish. This was called "Night String". Every boat fishing for swordfish employs this procedure. The main feature of this method is to cast the line at night keeping the hook in the upper layer of the waters using octopods as bait whereas • the long line for tuna fishing is usually not cast at night. MM. 4

• The area designated as the fishing ground for swordfish in the region of the Northern Pacific Ocean is shown in Fig. 1. The fishing ground opens in August at the Eastern Coast of Hokkaido near 45 0N.and closes in March at the east side of the Izu-retto (Islands) near 28 °N. In general, the fishing ground was not extended southward beyond the zone described above and it was eventually diminished after April. This may mean that the entire fishing ground would be in the waters between the Polar Front and the Subtropical Convergence. It is also predicted that a seasonal northward movement of the fishing ground may exist to a similar extent to that of the seasonal ' southward movement, vet this is not confirmed. The rod-shaped fishing ground, formed in the area of the Sanriku Coast during the period of June to August, could be an indication of north- ward movement of the fishing ground. Thus, it is very important to resolve the mechanism of resources supply and to study the actual state of the northward movement of the fishing ground with regard to young swordfish which are distributed in the southern waters down to the Subtropical Convergence.

Matured eggs and larval stage

a. Eggs of mature ovardes. Mature swordfish eggs are ovarian eggs of the fluid state so-called "mizuko" in Japanese which are completely separated from the surface laver of the oophorium. A part of the "mizuko" was collected and soaked in sea water cp r a while, and then fixed with 10% formalin solution. This specimen was obtained from the swordfish, its size was 170 cm 5

in length, caught at these bearings: 220-31'SJ 174°- ** 24' W.in June 1954. The eggs were fully spherical and the diameter of each egg was 1.6 mm on the average of 100 eggs, with the range of 1.5 mm miminum to 1.68 mm maximum. The outer- membrane of the egg was transparent and colourless. The surface of the egg's outer-membrane was not smooth but it was folded similar to the shape which can be seen on the surface of a watermelon.

It is not clear whether the folded state of the egg membrane was natural or caused by fixation procedures or immaturity of the egg. Some of the eggs contained only one vacuole of oil and others contained several smaller vacuoles of oil. Some of the eggs contained several tiny oil droplets in every egg-yolk. The diameter of the oil vacuoles were approximately * to 1/5 of the diameter of the egg if only one oil vacuole was present. The colour of the vacuole was pale yellow. The egg-yolk was often shrunk to form a distinctive space between the egg membrane and the egg-yolk, and the appearance of the space was similar to the surrounding space of a fertilized egg.*** In thesè eggs, every egg-yolk of white turbidity showed some granular forms after an intensive solidification phenomenon had taken place (Plate 1).

**The specimen was given by Mr. Sukeo Takahashi. The weight of the ovary and other details were not known. ***It seemed to be caused by the soaking process of the eggs in sea water before the eggs were fixed for preparation of the specimen. 6

• From these properties, it is predicted to be a kind of floating egg. One of the most distinctive characteristics of mature swordfish eggs is the diameter of egg (1.6 mm) which is the largest among tuna and marlin families. b. Materials of larval swordfish The samples of larval swordfish were obtained during the period of 1949 to 1958. The number of research navigation tours carried out during the above period was

97, and the number of items investigated was 1514. The major zone of waters covered during these investigations o o o was 110 180 E,of longitude and 35 1\1,- 10 0S,of latitude. 110 Some of the local zones in these studies were 60 0E.of longitude (2°S1 of latitude), 132 °W of longitude (24 °S, of .

latitude), and the south most limit was . 25°S, of latitude o o (110 E.of longitude) in the Indian Ocean and 28 S, of latitude (155 °E,of longitude) in the Pacific Ocean.

The time of investigation was distributed over every month but a much higher frequency of investigations occurred in the Western Pacific Region from the standpoint of the zones for the fishery waters. As a result of this, there was a lack of investigation in certain months in other regions, whereby the materials were heterogenously collected in general. 110 Larval swordfish were caught mainly by the catching procedure using a round type of a net which was hung at the *A . large type of net possessing a mouth of 1.5 m in diameter or a 2.0 m ring attached to the net (4x4,200 holes); the wbolesize of

the net was 37 holes/inch. 7

side of the ships and passed through the surface of the waters. The other method for catching larval swordfish was to pass through the deeper layer of water with the net and then scoop the larval swordfish which were swimming in the surface water by use of (scoop net) while ships were parked atop the water. The total number of larval swordfish was 26. The data on the capture are shown in Table 1 and the zones of capture are shown in Fig., 2.

c. Morphology of larval swordfish.

Figure 3 (Specimen No. 24) (1) The total length of the larval swordfish show in F!ig. 3 (Specimen No. 24) was about 5.1 mm. This specimen kept well its original body structure except ** • that the tail part was slightly bent upward. The belly portion of this specimen was markedly enlarged in comparison with other specimen. It was probablly due to injestion of an excess amount of food. The body was of a somewhat elongated form, and the trunk was extremely long. The height of the body gave the greatest value at the posterior part of the head, but it gave approximately the same height up to anal part. ** There were 2 specimens of 4.4 and 4.5 mm in total body length in addition ot this specimen. Development of every part of the body was more progressed than the specimen, and was close to that of the larval swordfish of 6.4 mm in body length. During the fixation period of the

11› specimen, bending of the body and shrinkage of the tail part might be caused. 8

• The tail portion became narrow sharply and the urostvle extended in a straight form. The length of the head was about 1/8 of the length of the body. The eyes were large; the diameter of the eyeball was approximately 1/3 of the length of the head or was similar to the length of the 111 snout. Both upper and lower jaws were not elongated but the lower jaw was slightly more projected than the upper one. The opening of the mouth was so big that the posterior edge of the mouth was almost reached near the posterior end of the pupil. Above both jaws, there were relatively soft

cone-shaped teeth, 5 in the upper jaw, and 6 in the lower jaw. There was a bony supraorbital ridge above the eye's and there were four saw-toothed structures at the upper edge of the supraorbital ridge. There was a preorbital ridge which possessed a short_bony spine inside of the front part of the supraorbital ridge. There were four small spines facing backward at the posterior edge of the preopercle. The spine located at the corner of the preopercle was the longest one among 4 of them. The bony projections of the post-temporal bone were not found. There was a nostril at the front side of the eyeball which appeared as a single concaved structure. The dorsal fin originated from the posterior end of the head, and gradually increased the height of the fin, and reached the highest value at the body portion above the anus. It's height was slightly lower in the central part of the caudal end, but was again higher and surrounded by the caudal end showing a symmetrical shape with the dorsal fin as it was closer to the end of the anus. • 9 A ventral fin was found to be rather lower in height between the area of the abdominal center to the frontal part of the anus. Fin rays of the dorsal fin were not noticed but the basic frames were found. The Caudal fin was thickened at the area which was equivalent to the hypural bone. Pectoral fins were more highly developed than other fins; the basal part of the fin was thickened and the posterior edge of the fin was circular. In this fin there were many fin rays but the number of the fin rays were not countable. Since this specimen was preserved in formalin solution, the original colour was largely lacking, vet it was recognized that the black granules 112 gl› were well developed all over the body from snout to caudal centre except the basal part of the dorsal fin showing star or branch-like shapes at the dorsal part as well as on both sides of the body. The colour of the body was darker in the posterior part of the body than the anterior one. However, the part of the body between the caudal centre and the body end was colourless except the small five black spots on either upper or lower parts of the urostyle. As a result, the posterior part of the body could be easily differentiated from the anterior part of the body. Figure 4 (Speciment No. 25) The total length of this specimen was 6.4 mm. This specimen was fixed in its entirety in the shape that it was, being slightly bent upward at the caudal part. The differences between the specimens described in Fig 3 and - 1 0 - • Fig. 4 are as follows in addition:to the different total body lengths being 5.1 mm and 6.4 mm respectively): 1. the length of the head was almost of the length of the body since both upper and lower jaws were more extended; 2. the bases of the fin rays in each vertical fin were clearly seen and the number of fin rays was partially countable; 3. various bony> projections on the head were shown • distinctively. Both upper and lower jaws were slightly bent inward creating the shape of a bill. The lower jaw was slightly more projected than the upper jaw. Teeth were mnall and cone-shaped, numbering 13 in the upper jaw and 15 in the lower jaw. A pair of small teeth facing toward the front were located at the tip of the upper jaw. The

supraorbital ridge was high, 5 spine-like projections were in a saw- tooth shape, and a cranial spine was seen in the back side apart from these projections. The preorbital ridge was a spine, while the temporal spine located at the posterior part of the head was a projection whose structure was rather narrow with an irregular shape at the tip.

The spines of the preopercle were in two lines and each line contained 2 spines. The spines in the front line were short, while those in the lower line were the longest. Under the articular, a spine was attached facing downward. The bases of each fin were seen but they were not clear in the front part of the dorsal fin; e.g., 43 bases were seen in the posterior part of the dorsal fin and 12 bases were counted in the anal fin. The far edge of the pectoral fins were round in shape with 12 dermal supports at the upper part of the fin. There were some dermal supports at the bottom part of the fin but they were not clearly • countable. Arrangement of the black pigment of the body showed no significant difference from the speciment of 5.1 mm in body length (Fig. 3) but the colour of the snout was extremely darker than other part of the body. An increased number of star shaped small black structures were seen in upper and bottom portions of the urostyle and also seen in the fin which was around the urostyle. The number of muscular nodes was not able to be determined by appearance. Figure 5 (Specimen No. 22) Total body length was 8.2 mm This specimen was damaged at the lower jaw and left eye. Since the caudal part was extensively crooked towards the left-handt, Figure 5, drawn in streched form, appears to be slightly shrunken in the tail region. Its head became large due to the elongation of both upper and lower jaws; as a result the ratio of body length/head length was 1.82 and that of head length/snout length was 1.92. The upepr jaw was slightly more projected: on its tip thee were two hod-silapd teeth which faced frontward; and on its surrounded edge there were 15 cone- shaped teeth in a row. On the surrounded edge of the lower jaw, there were 10 cone-shaped teeth in a row, and the teeth were rather smaller than those of the upper jaw. However, the number of teeth at the posterior part of the lower jaw was difficult to compute because this particular portion of the specimen was damaged. 11 3 The number of the - preorbital ridges at the head part was 3, and the supraorbital ridge consisted of 9 members in the shape of saw-teeth. The number of cranial spines and temporal spines was one each which projected from the skin. Spines of the preoperculum were in two rows; 3 spines were in the anterior row and 2 spines were in the - 12 - posterior row; in particular the 2 spines of the posterior row were larger. Under the articular a small spine was also seen. The dorsal fin was missing on both sides (dorsal and ventral parts) at about the centre zone between the anus and the caudal end, thereby it was divided into 3 fins; dorsal, caudal, and anal fins. The dorsal fin began at the upper-posterior end of the operculum and was highest at the upper part of the anus. The soft dorsal fin at the anterior part of the anus was slightly thickened to a semi-circular shape (0.28 mm of base length and 0.24 mm in height) at the lateral line which was close to the anterior end of the anus. In this soft dorsal fin, there were not any structures for fin rays or the basal forms of them. The number of the fin rays of each fin still did not reach the defned number; yet there were 40 in the dorsal fin, 15 in the anal fin, and 10 in the bottom part of the caudal fin surrounding the urostvle; the number of the fin rays of the upper part of the caudal fin was uncountable because the structures were too thin. In the pectoral fin there were 7 thick fin rays at the upper part of the fin and 5 thin fin rays at the lower part of the fin. The surface of the body was smooth except both sides of the ventral part of the trunk where a row of scales appeared as spine- like projections. On the surface of the body, there were black granules on about 2/3 of the.upPer part of the body except the caudal part, especially dark in colour in the area between snout and upper part of the anal fin. Small black spots were scattered on both sides and the bottom side of the tip area of the lower jaw, and were also on both upper and bottom parts of the urostyle in the caudal zone as well as on the caudal fin. - 13 -

• Figure 6 (Specimen No. 2) :Total length of this specimen is 11.0 mm. Since details of this specimen were already reported (23), characteristics of this specimen will be briefly rewritten here and the unreported informations will be also added here. The upper jaw (maxilla) is more projected than the lower jaw (dentary). There are 4 spines on the preorbital ridge, 9 spines on the supraorbital spine, and 1 cranial spine on the area of the slightly posterior side from the above structures. The tip of the temporal spine of the posterial part of the head has 3 divisions. There were 4 spines at the posterial edge of the preopercle; 2 of them in the front row were extremely short but the other 2 of the back row were much longer. There were 3 small spines under the articular bone. Scales looked like spine-like small projections which were in two rows: a row was located along the base of the dorsal fin (this row of spines will be called as "dorsal line" hereafter) and the other row was located along the line from the base of the anal fin through the pectoral fin to the base of the caudal fin (this row of spines will be called "ventral line" hereafter). The numbers of spines were 46 in the former line and 39 in the latter, and spines of both lines were relatively large in size. Under the dorsal line described above, 2 sub-lines of spines ran from the point closely located behind the base of pectoral fin to the upper section of the central part of the anal fin (these 2 rows will' be called as "the second- and third-

lines" hereafter). The spines of the second-line were smaller than those of the dorsal line and the ventral line described above and the line of spines 'deviated slightly from a straight line. On the other hand, there were 4 more lines of spines between the third-line and the ventral line starting from the posterior end of the pectoral fin and ending at - 14 -

• the upper part of the anus although the lines were irregular. The length of the spines in these 4 lines were shorter than other spines and the distance between spines was larger than that between other spines. There was only one nostril which is guitar-shaped due to constriction of the central part. The numbers of teeth were 22 in the upper jaw and 24 in the lower jaw. The dorsal fin consisted of a base and was ompletely separated from the caudal fin. The number of the dermal supports of the fin was 41; the first 3 dermal supports were extremely lower but others were high. The number of the fin rays of the anal fin was 16, the first 2 were slender and closely located together. From the third fin rays of the anal fin, the length of the fin rays was much longer than that of the others, but that of the fifth and further ones, was more or less uniform with the syrIltric relation to the dorsal fin. The posterior end of the caudal fin was round in shape. The number of the fin rays of the caudal fin was 14 in the lower fin, and there were thick in size. .However, the upper fin consisted of many finer fin rays, thereby it was difficult to compute the number of the fin rays. The dermal fin located in the front part of the anus was thickened to a circular shape of a 0.48 mm in basal length and 0.32 mm in height. The urostyle was rather elongated, and the formation of the hypural bone was greatly advanced. The colour of the dorsal and upper parts of the body was dark blue at the time immediately after the sampling. However, the bottom parts of the lower jaw and the • guanine- operculum as well as the ventral part of the body were a like silver-white in colour. As a result of the long period of soaking in the formalin solution, the colour of the specimen faded; the dorsal part and both sides of the body were pale dark-brown, while the lower jaw and the ventral part of the body were pale gray. 114 Fig. 7. (Specimen No. 3 ). Total body length was 27.4 mm . ( Details of this specimen were already reported. See reference number 23). The body was intensively elongated towards both directions forward and backward. Growth in the height of the body did not accompany the elongation process, thereby the general feature of the body was slender and long. The ratio of body length/body height was

11.8, and that of body length/head length wa-,3 1.85. This means that no extreme change was observed. The upper jaw was longer than the lower one, and the difference between the length of both jaws was equivalent to the height of the body. There were 9 spines on the supraorbital ridge in the head, 2 spines at the posterior part of the head, 5 spines on the preorbital ridge, and 2 spines on the supratemporal spine. There were 2 lines of spines on the front operculum; 2 spines in the front line were slender but 2 spines in the rear line were much thicker and longer than those in the front line. There were 3 small spines on a ridge which was located at the bottom end of the posterior gart of the lower jaw. The situation of teeth at the tip of the upper jaw was not known because the front edge of the upper jaw was damaged. There were many cone-shaped teeth, 29 on the side and 30 on the lower jaw. The nostril was divided into 2 holes and a flap was between the 2 holes. The height of the dorsal fin was approximately the same as that of the anal fin which was even slightly higher than the • maximum height of the body. The numbers of fin rays of the dorsal' and anal fin were 44 and 17 respectively. The caudal fin was rather long and was round in its posterior edge without any pointed shapes. The location of the pectoral fin was high and the shape of the pectoral fin was rather sickle shaped. Two spine-like projections were corne out of the base of each scale. Spines were also seen on both jaws (upper and lower), snout, face, and posterior part of the head. The line of spines (similar to the size of the ventral line) was observed on the

lateral line between the isthmus and anus. • These characteristics were different from the specimen of total body length of 11.0 mm (Fig. 7). The spines of the dorsal and ventral lines were large

• and they were in a line with uniform size from the posterior part of the head to the caudal end. The second and third lines of spines located between the upper part of the central caudal fin and the rest of the caudal fin were irregular in shape. There were 5 lines of small spines in irregular shapes from the back point of the basal part of the pectoral fin to the upper part of the anus between the third line and the ventral line. The,pelvic fin looked like the shape of tongue which possessed a short basal part; the length of the basal part was 0.32 mm and its height was 0.44 mm. . The pelvic fin was thick and fat, but the fin rays of the pelvic fin as well as other particular structures were not found. Black bodies were seen on the fin supports of the 13th-16th,

the23rd-25th, the 31st-34th, and the 39th-41st in the dorsal fin and on the last 5 fin rays in the anal fin. - 17 -

• Fig. 8 (Specimen No. 19) Total body length was 73.0 mm. We caught the larval swordfish, which was swimming on the surface of the water, by use of a hand net (scooping net) and the larval sword- 115 fish was fixed with formalin while the fish was still alive. During the period of sampling, tips of both upper and lower jaws as well as a part of fin membrane were damaged because the fish tried hard with its snout to flee from the net. The dorsal part of the near central part of the body was bent in approximately one and a half of a right angle (in shape of < ) . (*when a living larval swordfish was fixed, the body was used to be crooked in < shape. This is the same phenonemon that was found in specimens 2, 4, 5, 10, 16, 17, and 10 The body was slender, and the ratios of body length/body height and body length/head length were 14.89 and 2.04 rr.,spectively. ,Both 'jaws were extended to the spear-like shape. The upper jaw was longer than the lower one, and the ratio was 1.24 andthat of head length/snout length was 1.26.

Various bony projections and spines in the head part were not formed proportinally tothe growth of body, but they were in the tendency of degeneration. The location of the supraorbital ridge originated at the upper part of the anterior edge of the eye ball and passed over the eye-ball and ended to the upper edge of the posterior part of the front .operculum. The spines were rather short and 16 of them were assembled together but 2 of the other spines were located in a remote part. The preorbital ridge usually started in front of the nostril and ended above the cnetral part of the eye-hole. The number of spines was 10. Temporal spines were relatively short but 3 of them were noticeable. Spines of the preopercle were lined in 2 rows; the spines of the front row were extremely short and their number

was 4, but the spines of the rear row were larger than those of the - 18 -

• front line and their number was 2. In:bottom edge of the lower jaw, bony projections were well developed into spines which were numbered to 9 and of saw-teeth shaped. Spine-like scales were also well developed , especially the scales with four lines of spines, being exceedingly distinctive. Above all 2 lines of spines at the dorsal and ventral lines were the largest in size being similar to the length of eye-ball. The line of the dorsal spine started from the posterior part of the head and continued along the outside of the dorsal part, and ended at the centre of the caudal support. Spines in the front part of the body were rather short with the formation of 2 - 3 spines from each base, and gradually increased their size to the maximum at the centre part with the formation of 4-5 spines in an upward direction at each base. On the other hand, the line of the ventral-spine began at the narrow part of the isthmus and continued along the exterior side of the ventral part, and reached the caudal support. Spines of the anterior part of the body were small but reached a maximum size at the posterior part beyond the anal fin. The number of spines developed at each base was 3 - 4, and the tip of each spine was hook-shaped. There were a second and third line of spines between the lines of the dorsal and ventral spines, and the size of the second and the third lines of spines were smaller than the lines of dorsal and ventral spines. The secOnd line of spines ran from the slightly upper part of the centre of both sides of the body, in parallel to the line of dorsal spine, to the caudal end where both lines of spines were . joined. The third line of spines, on the other hand, began at the posterior part of the gill opening and ran through a slightly lower position than the central part of both sides of the body in parallel to - 19 -

the second line of spines. The size of the spines in the third line of spines was similar to that of the second line of spines. There were many lines of small spined scales between. the second spine-line and the ventral spine-line, especially more spine-. lines in the ventral part than those in the caudal part. There are 2 other irregular spine-lines between both ventral spine-lines on both sides of the body. In addition, other small spine-lines appeared at various parts, such as snout, operculum, and the surface of both upper and lower jaws. Two to 4 spines were developed at each base of these spine-lines. The number of fin rays of each fin was 47 in the dorsal fin, 16 in the anal fin, 18 in the pectoral fin, and 13 and 14 in the upper and lower dorsal fins respectively. A lateral keel was not developed. gl› In the formalin-fixed specimen, the colour of the body was brown except the grayish ventral section, there were 9 lateral stripes. In the central part of each side of the body,.there was a black line between the point in front of the anus and the caudal end. Black bodies were distinctively shown in a shape of stripes on the dorsal fin where the lateral stripes were joined. In the anal fin, the fin rays of the fin from the llth to 16th were pale black in colour. Four of the fin rays located in the centre of the caudal fin were slightly shorter than those of others, thereby the centre of the fin was concaved to give the tendency toward a pointed shape. The central part of the fin was black in colour. Specimen No. 20. Total body length was 80.0 mm. The height • of the body was slightly taller than speciment No. 19. The ratio of body length/body height was 12.69. However, the ratios of body length/ head length and length of upper jaw/length of lower , jaw were 1.99 and - 20 -

• 1.25 respectively, and the values were similar to those of specimen No. 19. Various bony spines on the head section were relatively small in size. Numbers of spines were 19 on the supraorbital ridge, 5 on the posterior part of the supraorbital ridge, 11 on the preorbital ridge, 6 and 2 on the front line and the rear line of the anterior operculum respectively, and 9 on the bottom edge of the lower jaw. There were 4 lines of spines which ran laterally on both sides of the body. The size of the spines were relatively small, thereby a lesser difference in the size of spines from other spined scales was noted. There were many spined scales on both upper and lower jaws. However, they were lacking in the anterior part from • nearly the centre of both jaws. The teeth of both jaws were sharp and cone-shaped, and the •eeth of the upper jaw were larger than those of the lower jaw. The number of teeth on one side was 73 on the upper jaw and 93 on the lower one. The fin rays at the centre of the caudal fin were short and tips of both upper and lower folk fins of the caudal fin were rounded with slight sub-division. d. Season of appearance of larval swordfish. Table 2 shows the catching season with respect to individual waters. According to this information, it would be the trend that higher catching of larval swordfish occurred during the period from 116 spring to summer in each water region. It would be risky to predict

111› the season of appearance or distribution of each region of waters for larval swordfish from only the catching results, bbtained by use of the - 2 1 • larval swordfish catching net which is high in incidental occurrence, because time and region of waters investigated were not uniform; also difficulty arises in catching the larval swordfish by means of the conventional net pulled by fishing boat due to the extraordinarily speedy motion of the larval swordfish which will be described later. However, the season of appearance for larval swordfish and distribution over the regions of water described in the following section were relatively well agreed upon thereby the informations here was useful for prediction of the spawning season or spawning region. e. Swimming depth of larval swordfish.

(21) Information reported by Taning was on the collections • 0 to 30 m of water depth. Conventional investigations in our studies were done by use of a boat pulling a net and hand scooping net for larval swordfish in the surface layer of the water. Therefore, water depth of catching in our investigation was 0 to about 2 m, and no information on further depth is available. However, recently we collected the samples from 3 layers of waters near the Caroline islands; such as; surface, 10 - 20 m, and 40 - 50 m by the boat-

pulling method. The results are shown in Table 3. The range of body length of the larval swordfish was

approximately 4 - 6.4 mm. The number of larval swordfish caught were 3. (We pulled the boat 3 times per larval swordfish) in the surface layer of the water, and only once in the laver of

10 - 20 m, but no larval swordfish was caught in the layer of

• 40 - 50 m. Although this information was based on insufficient data, - 22 -

• one may realize that the tendency of highest occurrence of larval swordfish was in the surface layer of water within the limit of these data. The observations on larval swordfish swimming in the

surface layer of the water were reported (24), but the summary is reiterated here. "During the daytime the fishing boat stopped on the region of water of mid-lower latitude to survey the ocean, we occasionally observed that larval fish passed by our boat side

swimming in the layer of 5 - 8 m of water depth. The first observation on this matter was done in August of 1951. It was a fine day without wind. We occasionally noticed a slight movement of water on the calm surface like the sea-surface covered with oil. Upon placing the scooping net which had a 4 m-long rod, the fish almost instantly disappeared deeper into the water. We repeated this effort time to time, but we were finally•able to scoop a fish on the 19th of August and first realized that this was a swordfish.

On that day, we observed 12 appearances of swordfish in approximately

90 minutes, but we were able to scoop only 1 fish by the use of a scooping net. On the same day, however, we were unable to catch any fish by the use of the boat-pulling net of larval swordfish." In addition to this, we were able to catch the fish with a scooping net in 1952, 1954, and 1955, but we failed to catch the fish in most cases in the surface layer of water by use of a boat- pulling net for larval swordfish. Difficulty in catching larval fish by use of the net for the larval fish would be due to the 117 speedy action. of larval swordfish, thus the fish may rapidly run away or may sink down to the deep water layer where the net could not reach when the fishing boat was approaching. We noticed the - 23 -

• larval swordfish swimming in the surface layer of the sea only on windless calm days. This is probably due to the colour of the body (dark blue-indigo on the dorsal part and silver-white in the ventral part of the body). It was difficult to discover the larval fish from a boat on windy days in particular. It was predicted from the collected information that larval swordfish less than 70 mm in total body length may be swimming near the surface of the sea regardless of the weather or climate, day or night. f. Food habits of larval swordfish. We examined the contents of digestive tracts using a part of our specimens and the results are shown in Table 4. Some of the specimens were lacking food materials in their digestive tracts, but the specimens of 1•ss than 14 mm in whole body length contained animal plankton and other specimens contained larval fish. It was a trend that size of the food was rather. large in contrast to the body length. Arata (1) reported that the specimen of 7.8 - 9.0 mm in body length only contained animal plankton, and other ate larval fish, especially Scombirds, Exocoetids, Xiphiids, Istiophorids, etc. We also observed such a tendency in our inVestigations. This trend was probably due to the depth of the swimming layer of the larval swordfish which would be similar to that of these larval . III Morphology of young swordffsh Sample materials were young swordfish obtained from the ** stomach of , marlins, bigeyes, etc. and from hook fishing.

*The number of young swordfish obtained from the stomach content of such adult fishes was approximately 250. - **The minimum size limit of young swordfish caught by hook fishing was

approximately 800 mm in total body length. • - 24- The number of specimens used for measurement of body structure was 28. (Data on the collection of young swordfishare shown in Table 5). Seven specimens out of 28 young swordfish are described as to their morphological characteristics. However, explanation of body forms is much simplified and will be discussed in detail concerning the whole period of growth in the next section on "Morphological dhange as growth proceeds". The colour of the specimens was based on observations conducted on the specimens after a substantial length of time following the procedure of formalin fixation. *** Specimen No. 1 Total length was 160 mm (body length = 16.2 mm). This specimen was obtained from the stomach contents. (See Fig. 17A). Body form: Shapes of the head and fins were similar to those of the larval swordfish, specimen No. 19 (Fig. 8), but the length of the snout and lower jaw were relatively short. Conversely, the pectoral fins were long. The caudal fin was not yet markedly pointed. Colour: Since the epithelial layer was in the early stage of gastric digestion, the colour of the body was not clearly shown, but several lines of lateral stripes were noticed in both sides of thebody.

*** The length between the posterior and of the upper jaw and the terminal point of the hypural bone. This will be the same here- after. In this section, this is called body length. (In the

Appendix in Table 2, body length is based on the same definition.) - 25 -

** 113 Scales: The whole body was covered bv . spinous scales , among • and teeth which marked ones were seen as lines of small spines on each side of the body. This is similar to that of specimen No. 19 described above, but development of spines was not as distinctive as that of the previously described one. The lines of small projections were more distinctive in the caudal part than the trunk part of the fish body. Most of the small projections possessed five spines. The saw-tooth shaped projections above the eye-hole and at the bottom edge of the posterior part of the lower jaw as well as the spines at the corner of the preoperculum were distinctively observed in the previous specimen. However, these projections were in an almost degenerated state in this specimen.

In constrast to specimen No. 19 (Fig. 8), teeth were also in a stage of degeneratien. There were tiny cone-shaped teeth developed at the edge of the upper and lower jaw, but those of the upper jaw were situated more spaciously (slightly long cone-shaped teeth were grown with some space between them) than those of the lowcr jaw. • Those •. of the lower jaw were in the degeneration process.

** Spines were developed facing towards the posterior end of the

body. - 26 -

Specimen No. 6 The total length was 204 mm (body length gl, was 117 mm). This specimen was obtained from stomach contents. * * * (Fig. 9) 1 19 Body form: No significant difference was found from the previous specimen 1, but there developed a strong trend that the caudal fin was pointed in 2 parts. Colour: It was surprising that this specimen was very little attacked by digestive enzymes in spite of the fact that the specimen was obtained from stomach contents of other adult fish; as a result the colour of the body surface and various fins as well as sripes were observable. Colour of the body was as follows: the parts of the snout, upper head, and posterior eye were tea-like brown; the body trunk and dorsal side of the caudal part were also tea-like 15rown; the ventral side of the caudal part was white; both sides of the body showed 9 tea-like brown,lateral stripes on a pale-grayish back- ground. Colour of fins was as follows: the dorse.-1 fin was dark brown; the basal part and tip of the pectoral fin were pale gray and dark brown respectively; the front part of the anal fin up to the 8th fin ray was colourless, while the posterior part of the fin was dark brown; the whole caudal fin was brown, especially the basal part of both the upper and lower pieces of the caudal fin, these being darker brown. *** The shape of the fins was extrapolated on the basis of the length were considerably of the fin rays since the dorsal and anal fins damaged. - 27 -

Structures of bony projections on the head, teeth, and scales:

• the bony projections on the eve-hole remained in trace- form but those on the front operculum had disappeared through degeneration. The teeth were also in the process of degeneration; some cone-shaped teeth still remained at the posterior part of the upper jaw, but generally thev were in the process of conversion into villi-shaped teeth. The small projections on the row of scales on each side of the body were sometimes seen to be 6 spines in number. The length of the spines were relatively shorter than for specimen 1, and they are in the degener- ation trend. Specimen No. 9 The total length was 269 mm (body length was 150 mm). This specimen was obtained from the stomach contents of other fish caught. Body form: A figure of this specimen is not presented but its body form was similar to figure 17.B. The dermal supports at the anterior part of the dorsal and anal fins were taller than the posterior part. In the anal fin especially, a tendency was noted that an anterior fin (folk-fin) was already formed. Colour: Lateral strines on both sides of the body were seen but they were exceedingly faded in colour. Teeth and Scales: Teeth were similar to those described in Specimen No. 6. The situation for formation of tiny projections in lines on both sides of the body was relatively sparing in comparison with smaller specimens.

Density of the projections was lowered because the formation of the tiny-projections was not accompanied by growth of the body. • The shape of th è tiny projectionswas also changed. .For

example, every base of the tiny projections was so enlarged

that spines were covered by the development, thereby the length of spines became relatively shorter. The finer structures of spine-like projections formed between the

lines of the tiny spines were also in a state of progressed degeneration. Viscera: The tubular structure of the intestines was simpler and did not show the typical zigzag shape characteristic of the swordfish (see Fig. 10). The anterior part of the intestine was especially larger and the intestinal walls were thin and semi-transparent. The posterior section of the intestinal tubules were slightly narrower and the tubular walls were so thin that the intestinal contents could be seen. The transparent intestinal tubules continued straight way to reach the rectum. The wall of

the rectum was thick and was not transparent, thereby it could be easily differentiated from the intestine. The size of the liver and caecal mass was relatively small in comparison with the large specimen which will be

described later. In other words, the intestinal part could

occupy most of the _body space.

Specimen No. 18 The length was 219 mm. This specimen was obtained from the stomach contents of a large fish. (See Fig. 17 - • D) . - 29 -

Body Form: The front part of the upper jaw was lacking but one could predict from the equivalent size of the specimen (Fig. 17-C) that the length of the snout would be relatively short (the length of the snout was approx- imately 50% of the length of the body) in contrast to the smaller specimens (Fig. 17-A, -B, and Fig. 9). Tendency for formation of the anterior fin-flaps (folk-fin) was recognized on the dorsal fin as well as on the anal fin. Colour: The lateral stripes on both sides of the body were almost nonexistent. The anterior flap of the anal fin (up to near the eight dermal support) was slightly pigmented. Lateral 120 line: The lateral line on both sides of the body was vaguely noticeable, and appeared from underneath the dorsal fin, running first downward, and then straightforwardly to the caudal fin through the central part of the body in the rest of the posterior part of the t-ody beyond the pectoral fin. Protuberance of caudal vertebrae: The section of the caudal vertebrae was not too much inclined towards vertical. ** The keel(horizontal protuberance) was not formed.

The lateral line was also recognized in the s'pecimen of which the 111, body length was 190 mm. ** In the specimen of 290 mm in body length, the section of the caudal vertebrae was quite vertically inclined. The keel (horizontal protuberànce) was formed on both sides of the body but not yet fully developed. The pointed tip of the caudal fin (folk-fin) was also not fully developed and its angle was approximately 30 ° . Teeth and scales: The teeth in the upper and lower jaws were in a state of

progressed degeneration and shcAed villi-like shapes. The tiny projections of scales were distinctive in the caudal part but those of main body trunk were already un-clear. Viscera: Intestinal tubules in specimen 9 described abow were transparent but the intestinal walls of this specimen were somewhat thicker, whereby they were semi-transparent. The liver and caecal mass were relat.ively large in size. _pecimen No. 23. The total length was 554 mm (body length was 302 mm). This specimen was obtained by the hook fishing *** method. (See Fig. 17-E, plate 1). Body form: One of the characteristics of this specimen was the **** increased width of the snout; the width of the snout was approximately 7% of the length of the snout (See Fig. 15).

**hi specimen was captured using a hook for tuna fishing. The ventral part of the swordfish was hooked. **** The width of the snout was defined as the width of the centre of the snout. - 31-

• The tendency tO form the anterior flap in the dorsal fin as well as the anal fin was evident but degeneration of the dermal supports of the posterior part of both fins had not yet progressed. The morphology of the last 3rd to 4th dermal supports was different from that of the anterior dermal supports; the distance between the dermal supports was narrower and the size of the dermal supports were thicker, and a tendency to divide into two bases in both dorsal and anal fins was observed (plate 1). The section of the caudal vertebrae was inclined vertically to a considerable degree. The formation of a keel (horizontal protuberance) was also observed but it was still in the initial stage of its . development. Tbe opening range of the upper and lower fin- flaps of the caudal fin was not as large as that of an adult swordfish. ***** Colour: The dorsal side of the body was dark brown but both sides and the ventral part of the bodywere pale brown in colour. The underneath of the ventral part was lighter in colour than the other parts of the body. On the other hand, the inside of the lower jaw was dark brown. The dorsal, pectoral, and caudal fins were all dark brown but the anterior fin-flap (folk-fin)

***** Nakamura (13) reported the- colour of the body while the fish was alive - total length of the specimen was 660 mm: "dorsal part was dark blue, both sides of the body were light and the bottom side • was white. The colour of each fin was similar to that of the body. The lateral stripes on the body surface and fins were already not recognizeable", - 32-

• of the anal fin was pale brown (However, the tips of the dermal supports were dark in colour). The posterior part of the body or the part that was covered with the muscle due to the degeneration process was dark brown. Lateral .

stripes on both sides of the bdoy were not found. Lateral line: There was a lateral line on each side of the body, which ran in the direction of the body axis and ended at the lateral keel. In the zone slightly above the lateral line, there were 36 short lines (1 - 2 mm each in length) which were drawn vertically against the body axis. Distances between these-vertical lines were not uniform but with some irregularity. Teeth and scales: The teeth were degenerated, thereby some file-like teeth were noticed inside of both upper and lower jaws like those of an adult swordfish. The line of tiny projections on both sides of the body was in the process of disappearance, and was only seen on the dorsal and ventral sides of the caudal part. The spines of tiny projections became dull at their tips and were in the stage of covering over with base. Viscera: Intestinal tubules were opaque and were not uniform in size. Place to place they showed a lumped shape with constricted form. The formation of septum was seen inside of the intestinal tubules. The phenomenon seemed to be in the initial process for folding of the intestinal tubules. Specimen No. 25 The total length was 841 mm (body length was 415 mm). This specimen was obtained by hook fishing (Plate 1). - 33 -

• Body form: It was similar to an adult swordfish at a glance; but, details were different from the adult fish; for example, with respect to the shape of the dorsal fin, the values of upper jaw/lower jaw, etc. The length of the snout was relatively longer than that of specimen No. 23 described above, and the value of the ratio of upper and lower jaws was also larger (approximately 2.5). The pectoral fin was so well developed that the length of it reached about 30% of the body length. Each of the dorsal and anal fins was still one base structure. However, the dermal supports of the anterior part of both fins were developed in contrast to a degeneration of the posterior dermal supports; the last dermal surTorts were also developed. As a result of • this phenomenon, each fin was divided into two fins. The several anterior dermal supports of the first anal fin were already covered with muscle to the extent that there might be difficulty in pulling out the fin rays. The central fin rays of the first dorsal fin were somewhat longer than those of the anterior or posterior parts of the fin as shown ****** in Fig. 17-F. . (It is approximately the same size as specimen No. 25). The sectionsof the caudal vertebrae and caudal fin were all developed in comparison with specimen No. 23.

******The figure of the dorsal fin was drawn in the standing form of • the fin rays. - 34 -

12.1 • There were some vacant hollows on both the upper and lower sides of the caudal vertebrae zone. The angle between both fin-flaps of the caudal fin was much larger than that of the previous specimen but narrower than that of an adult fish. Lateral line: The lateral line and the short vertical lines against the body axis were observed. The lateral line was a narrow and wavy curve, and was more difficult to find than the short vertical lines. Scales: The lines of tiny projections were almost in trace amounts due to covering by skin. The spined scales between the lines of tiny projections were degenerating to the extent of rough feeling when one touched the body surface. Viscera: They were not examined because the viscera of this specimen had been removed. However,.it was recognized that the folding phenomenon of the intestinal tubules had progressed to a considerable extent in the other specimen of similar size.

Specimen No. 28 Total length was 1,238 mm (body length was 573 mm). The specimen was obtained by hook fishing (Fig. 17-G). Body form: The body form of this specimen was closer to the adult fish than specimen No. 25. The length of the snout was relatively long and the value of the length of upper jaw/ length of lower jaw was approximately 3.4, which was smaller than that of the adult fish. The anterior fin- flap of each dorsal or anal fin was highly developed. The

posterior fin rays were in the process of being burried in -35 -

• the hollowed zone of the mid-dorsal line . The posterior fin rays of the first anal fin were completely burried, therefore each of the dorsal and anal fins was fully divided into two bases in appearance which was close to the form of the adult swordfish. The part of the caudal vertebrae was heavily inclined vertically and the keel (horizontal protuberance)was also developed. The caudal fin was also wide and two-pointed (folk-fin), which was similar to the adult swordfish. Lateral line: It was recognized yaguely. Scales: The lines of the tiny projections were degenerated to disappearance and their traces were shown as white spots. • Viscera: Figure 11 shows a ventral view of the viscera. The intestinal tubules were folded many times as they were seen in the adult swordfish which had typical intestitinal characteristics of a swordfish. The rectum was wider than the intestine with a thicker intestinal wall. The liver and caecal mass were larger than that of specimen No. 9 (body length 150 mm, Fig. 10). The shape of the liver was different from that of the Istiophoridae in that the central liver was slightly longer than both the left and right ones. The spleen was not found in the ventral view because it was located just to the rear side of the gall-bladder.

* 110 Fig. 17-G was also drawn in a shape such that the fin rays were standing after pulling them out. - 36 -

• IV Morphological change with growth

growth Arata (1) discussed the relative A of the swordfish with respect to the standard length of its snout, lower jaw, head,.bodA and eye diameter during the growth period. [The length between the posterior end of the operculum and edge of the hypural bone was defined as the body length: ii was approximately the same as the standard body length minus the head length.] However, he did not fully discuss the young stage which connected the larval stage with the adult in stage since he was lackingxadequate materials for the young stage. In this regard, we were able to clarify the overall • morphological changes which occur with growth during the period from the early larval stage to the adult stage since we obtained much material from the stomach contents of tunas and marlins as described above. We were also able to clarify the growth period as a whole a considerable extent. The changes involved with growth, particularly the changes in the head structures and fins will be discussed here. The length* between the posterior end of the 122 upper jaw and the edge of the hypural bone (the edge of the urostyle in the case of the larval swordfish) was adopted** as the standard (It will be called body length hereafter) for discussions pertaining to the relative growth of every • structure involved. [* The body length in the tables of the •- 37 -

appendix was approximately the same as the standard body

length minus the length of the upper jaw.] [ Arata (1) adopted the standard length for a base but the standard length contained the upper jaw which underwent extensive

changes dui;ing the growth period. Therefore, this procedure was not considered a suitable base.] When the body length is illustrated graphically, its logarimic values are plotted

along the X-axis. The values for the snout, lower jaw, pectoral fin etc. are plotted on the Y-axis as a percentage

againRt the body length. eceeee (see Fig 12-16). Veeeee The

information cited from other literature is shown in the figure with different signs.] In the examinations of every • young swordfish obtained from the stomach contents of predators, there were no differences between specimens coming from the

South Pacific Ocean and the North Pacific Ocean. Therefore, both were used together without separate handling. From the structures of the specimens deScribed in

the previous section, the growth period for the swordfish could be generally divided into the following 3 periods, which will be used in future discussions: the first period

is the period when body length is less than approximately

100 mm, the second period is . the period when body length

varies from 100 to 600 mm, and the third period includes all lengths which exceed 600 mm. The characteristics of each • period are as follows: spination (spine formation) of the - 38 -

• head part (it v:/ill ,be degenerated toward the end of this period) and development of body scales are observed in the first period; the stage of scale degeneration is in the second period; and finally the scales disappeared and the fish became an adult in the third period. Fin formation may also be changed with respect to each growth period. a. Morphology of the head part The relative growth of the snout showed 2 cycles of particular change in the whole growth period, twice increasing and decreasing in snout length in relation to body length when the figure was drawn by the method described above (Fig. 12). In the early phase of the first period (body length was approximately 4'mm), the snout length was

about 20% of the body length but it showed a dramatic and

positively allometric growth with respect to the body growth, and finally reached 75% of the body length when the latter became about 20 mm. After that, the snout length followed negatively allometric . growth. Thus, the growth phase entered the second period, and then the value of the minimum limit of about 50% snout length/body length was attained when body length reached about 200 mm. Thereafter, the relative growth of the snout again entered a phase of positively

allometric growth and reached a value approximately 80% snout length/body length at the end of the second period. - 39 -

Finally, the growth phase entered the third period as the body underwent further growth, and the relative growth of

the snout was again entered the negatively allometric growth phase.

The relative growth of the upper jaw has also exactly the same tendency as the snout.**** [**** There

was an isometric relationship between the length of the snout and the length of the upper jaw.] 123 The relative growth of the lower jaw followed a

path that was similar to that of the snout, during the period from the early stage of the first period to the early stage of the second period. After that it was, however, • different from the situation of the snout, and remained in the negatively allometric growth phase (Fig. 13).

The value of the length of the upper jaw/length of the lower jaw, or the relationship between the upper jaw and

the lower jaw will be discussed here in terms of its change with respect to growth (Fig. 14). The relationship changed

dramatically after the middle of the second period as was

predicted from the trend of the relative growth of the snout and the lower jaw described above. The ratio of the length of the upper jaw/the length of the lower jaw as approximately 1.0 at the early

stage of the first period, which meant that both jaws were • the same length*. [*Under the body length about 4.5 mm, the

lower jaw was slightly longer than the upper jaw.] However,

the value of the ratio moderately increased as growth pnx:eeded:

it was approximately 1.25 without any change from the time body lengtli was 10 mm to the end of the first period, then it was slightly increased at the beginning of the second phase giving a value of about 1.5 for the early part of the

second phase (body length 10-300 mm) but it rapidly increased

during a transition period with the boaderline at about 300 mm body length giving a value of about 3.5 late in the 124 second phase (body length 300-600 mm). The curve of increase gradually became flat when the growth reached the • third period; thus the length of the upper jaw was approx- imately 4.2 times that of the upper jaw when body length was 1,300 mm. After this stage, the relationship between the upper jaw and the lower jaw showed almost no change with

respect to growth.

As mentioned above, the curve, expressing the

change of the values of the length of the upper jaw/the length of the lower jaw, showed a tendency toward a sigrnoidal curve having a transition point near the period when body length was about 600 mm (it was the transition stage from

the second period to the third period). It means that the

relative growths of both the upper jaw and the lower jaw • were alike during the interval from the first period to the 41 1117

• beginning of the second period, but the relative growth trends were entirely reversed during the later part of the

second period, and then finally the trends of the relative

growth were alike again in third period. It was of interest to note that the relative

growth of the snout length of the swordfish followed the course of growth shown in Fig. 12. However, in order to discuss further this particular area, the relative growth of

the snout width (at the centre of the length of the snout

in relation to the body length and the changes occurring

with respect to the values of snout width/snout length, or morphological changes of the snout, were studied (Fig. 15). The ratio of snout width per body length was

approximately 11% at the beginning of the first period, but it decreased rapidly until the body length was 10 mm as growth occurred, then it slowly decreased to about 2% at the

end of the first period; thus the phase entered the second

period. During the second period, the ratio increased

approximately 5% (body length was 150-400 mm). After this period, the detailed situation was unclear but snout length seemed to decrease gradually with respect to the growth during the third period. The change in values of snout width/snout length

resulted in a form of combination with above mentioned values of relative growth of snout width and the relative

growth of snout length. L2

During the early phase of the first period, the values of snout width/snout length were higher than 50%, but as growth proceeded it decreased dramatically to 6% for the individual which had a body length of about 10 mm. After that it gradually decreased to 4% for the individual with a body length of about 30 mm, and then it lowered to about 3% at the end of the first period. During the second period, it gradually increased to nearly 7% for the individual with a body length of approximately 300 mm. After the third peric-d, the situation was unclear but there seemed to be a gradually decreasing tendency. With regard to morphology of the snout, the snout was found to be thick but short in the early phase of the first period, and then it elongated rapidly taking a very slender long form in accompaniment of growth. The width of the snout then again increased to become sword shaped in the early stage of the second period. No further significant structural change of the snout was observed from the later phase of the second period to the third period. However, it seemed to follow the trend of slight elongation. In the development phase of the swordfish from the beginning state having a thick-short snout to the typical snout form the so-called "sword like" or "broad bill" in the final stage of the adult swordfish, there seemed to be two steps: the first step for lateral elongation (after the early stage of the first period) and the second step for broadening (the early stage of the second period). - 43 -

125 111, The length of the snout in the second period was shorter than that of the first period. This phenomenon was

also observed among other marlins: it seemed to reflect a

tendency toward a large head with a short trunk as observed in the period of the larval stage and elongation of the

trunk occurred in the period of the young stage as well as the situations described above.

The figure on the relative growth of eye diameter

has been omitted here. However, the relative increase in eye diameter was simple: in the early stage of the first period, eye diameter was the largest* in a relative sense and then showed negatively allometric growth to a moderate

. degree as the growth continued, then it seemed to show • almost an isometric growth** after the second period. [*Precisely speaking, it was not the s,ize of eye diaeter but the length of the eye-ball which was approximately 14% of

the body length.] MLikewise, it was the length of the eye- ball, which was about 5% of the body length.] b. Morphology of the fins Pectoral fin (Fig. 16)

In the first phase, the pectoral fin was short (about 15% of the body length) and showed nearly isometric . growth with respect to the body length until the body length reached the 40 mm range. However, the extent of elongation of the pectoral fin was dramatic from the terminal stage of - 44 -

• first period to the early the stage of the second period, and the length of the pectoral fin reached about 30% of the body length when such has become approximately 400 mm. After the third period, elongation of the pectoral fin seemed to gradually decrease as the growth proceeded. Dorsal fin (Fig. 17)*** UceeeeThe figures of the dorsal and anal fins were drawn in a form such that the rays of the fins (dermal supports) were standing.] In the first period, both dorsal and anal fins were on one base but no sign of division into 2 bases were observed. The front part of the fin rays were higher than • those of the central part of the fin and the formation of the fins were not yet fully developed. When the body length reached about 200 mm, now entering into the second period of growth, the height of the fifth ray region in the dorsal fin was higher than the 10th ray region, thereby the shape of the fin showing a sign of anterior fin formation (sickle-shaped). However, the length of the central fin-rays was still the longest. From the time body length was about 300 mm, the height of the anterior rays was higher than that of the central part of the fin; thus formation of the sickle-shaped fin was carried out. The dorsal fin was still one base but 3 to 4 rays at the terminal part of the fin were different from the anterior fin-rays in their structure (as well as the distance • between fin-rays), thereby, the tendency toward differentiation -45- • (formation of the second dorsal fin) was observed. From that point the anterior dorsal fin developed as growth proceeded, but the posterior fin rays from the 10th fin ray region was so poor (called diminishing phenomenon) that the trend for division into 2 bases for the dorsal fin gradually became evident. The degeneration phenomenon of the posterior fin-rays seemed to pass the wave form to a gradual transition course starting from the anterior part of the fin-rays to the posterior part of them as shown in figuresD->W.> G in Fig. 17. The terminal fin rays were independent of the degeneration trend, whereby the formation of the second dorsal fin proceeded. In the specimen of more than 400 mm in body length, it was clear that the dorsal fin showed a

• tendency to divide into 2 bases. At the end of the second period, the dorsal fin was still in one piece throughout from the anterior part to the posterieœ part of the fin. The fin rays still remained in this period but the findings of the posterior part of the fin were almost covered with the dorsal muscle (dorsal ditch), whereby these changes in the dorsal fin proceeded to the extent that 2 bases were noticeable. When the growth phase entered into the third period, such a tendency was more distinctive and the typical form of the dorsal fin for an adult swordfish emerged. Changes in the anal fin were in parallel to changes in the dorsal fin but the changes in the former seemed to be slightly faster than in the latter (Fig 17). -46-

Caudal fin (Fig. 17) In the first period, the posterior edge of the caudal fin was still nearly in a straight-cut shape. However, it was clear that the caudal fin showed the tendency to form a forked-shape when the growth phase entered the second period. As the swordfish grew further, the formation of the forked-shape in the caudal fin also proceeded; thus the deeply 2-pointed forked-shape form which was similar to the

adult form resulted when the body length reached about 400 mm. The form of the caudal vertebrae zone had not yet significantly changed. When the body length approached approximately 300 mm, the caudal vertebrae was inclined in a 'lateral direction and the formation of a keel (horizontal protuberance) on both sides of the body was observed. As the body length reduced about 400 mm, the degree of lateral inclination of the caudal vertebrae was greater and the keel was also developed, whereby the form of the caudal vertebrae zone was similar to that of the adult swordfish. In other words, development of the caudal vertebrae zone was parallel to that of the caudal fin and both of them showed a greater similarity to the form of the adult swordfish at the end of the second period. -47-

• C. Colour, spots, lateral line, and séales Colour stripes and spots The spots of lateral stripes observed on both sides of the body and on the dorsal fin were noticed distinctively in the firs :t period of growth, but they gradually became indistinctive in the second period, and thendisappeared when the body length reached approximately 300 mm. With regard to the colour of the rays of the anal fin, the rays at the posterior part of the fin, which degen- erated with growth by burrying within the muscle ditch of the dorsal central line, showed a brown colour during the first period of growth, and became darker in the second • period. However, the rays at the anterior part of the fin, which was to be the first anal fin upon further growth, were colourless in the first period. Thereafter, pale pigmentation (brown) was observed when the body length reached about 200 mm in the second period, and was followed by a further gradual darkening process as the growth proceeded thereafter. Lateral line The lateral line of the swordfish was rather indistinctive in comparison with other fishes of the Istiophoridae, and its shape was also somewhat different. The lateral line seemed . to have two kinds of lines: one was a waxy curve which was located in the lateral direction of the body and the second consisted of the short lines (about 35 lines) which were located in a row above the lateral line cr,

-2+8-

• running in a vertical direction against the body axis with some intervals between adjacent lines. Both were unknown at

to what stage of the growth period they could appear, but the former (lateral line) was observed in the specimen whose body length was about 190 mm and the latter type (short vertical lines) was found when the body length reached about

300 mm. No changes were observed in the form of the lateral line, which consisted of the lateral wavy curve and the row of short vertical lines, throughout the second and third periods of growth. From observations on fresh fish bodies at the f -;_shmarket immediately after unloading, the lateral • line was so uncertain that it was not noticeable unless the black-brown membrane on the body surface was removed by rubbing. The row of short vertical lines was slightly elevated from the surface of the body.

Scales The scaling phenomenon was reported in detail by

Arata (1) and Nakamura and other (2). The phenomenon usually occurs to a greater extent during the first period of growth, but followed a path of degeneration in the second period and spines of the scales almost diappeared in the final period*.

[*With regard to the degeneration process of scales, a previous report (14) described it as "spines of scales seemed to have been lost or have disappeared". However, -49-

• from the results of our observations on scales of various degeneration courses, spines may not be lost but they probably

degenerate by process of burrying by their bases.] Among

the spiny scales on the both sides of the body, the lines of

spiny projection which were noticed distinctively were completely degenerated to the extent of disappearance as

were their bases as well. However, traces of other scales

were observed as a striation which located in the lateral direction on the body surface during the third period**. [**The observation done in the third period was under a macro operation.] d. Viscera

Morphological changes in the intestinal tubules 128 will be mainly discussed here. In the early stage of the second period of growth, the intestinal tubules were not yet in the typical zigzag form which was seen in the swordfish,

but showed a simpler tubule sh.ape. The intestinal wall was

thin so that intestinal contents were visible. As growth

proceeded, the intestinal wall became thicker and opaque in addition to the changes in its shape. In the specimen whose body length was about 300 mm, formation of septum inside the intestinal tubule was observed. Its appearance was no longer a simple tubule with lump-shaped and constricted

forms in various places. The formation of a septum inside the intestinal tubule was predicted as the early stage of - 50 -

the intestinal folding. The intestinal folding proceeded further at the late stage of the second period and the zigzag shape which was seen in the adult swordfish was also seen in the terminal stage of the second period. Although our observation was made under macro operation, the folding phenomenon of the intestinal tubules in the swordfish seemed not to be due to the bending in turn from one edge of the fine tubule to the other edge, but by following a course which involved firstly the formation of the septum inside the thick tubule and secondly the form- ation of folding thereafter. However a detailed mechanism of the folding phenomenon awaits future work by anatomical and histological studies. Besides the morphological changes of the intestinal tubules described above, the change in relative size of the liver and caecal mass occurred as growth proceeded. At the early stage of the second period (Fig. 10), the liver and caecal mass were relatively small (the summed length of both

organs was about 10% of the body length) but the intestinal part largely occupied the body space (approximately 20% of the body length). As growth proceeded, however, the former gradually became larger and reached approximately 15% of the body length in the last stage of the second period, but the latter folded and became placed into a relatively short body space (about 17% of the body length in the final phase of • the second period) (see Fig. 11). - 51 -

The ratio of rectum length to body length was almost not changed by growth, but it seemed to be slightly increased after the final stage of the second period*. [*The ratio of the length of the body trunk to body length also followed the trend of slight increase, which was larger after the final stage of the second period than before the early stage of the second period.] Mentioned above are discussions on morphological changes of various organs with regard to growth. The class- ification of growth periods described in the beginning of this section were highly suitable to the course of morphological changes in the broad sense and it seemed to be the proper • one. If the growth periods were further sub-divided, the stage belonging to body length being less than 10 mm would be differentiated as the early larval stage as opposed to the rest of the first period (less than 100 mm in body length). It would also be suitable that the second period (100-300 mm in body length) be divided into two, the early and the late stages, setting the boundary-line at body length about 300 mm**. [**The specimens obtained from the stomach contents of tunas or marlins belong to the early larval stage.] The third period was further divided into the early and the late stages by setting the Border-line in terms of body length by sexual maturity***. [***Approximately • 1,400 mm in body length.] - 52 - • Thus the growth periods were divided and called

the first, second and third periods; . the following names

seemed to be suitable: the first period or the larval stage,

the second or the young stage, and the early and late stages of the third period referring to the immature stage and the adult stage respectively. It was predicted that morphological changes were deeply correlated with the ecological changes such as food

habits, distribution, etc.

• - 53 -

• V Spawning

a. Situations of sample collecting from spawning area The important fishing ground for swordfish in the North Pacific Ocean may be considered as the area from the

Subtropical Convergence to 45 °N. Lat. rio:uthwd, if small fishing grounds like the coast of Cheju Island are eliminated. Almost no swordfish was caught further south in the Pacific Region beyond the Subtropical Convergence. However, according to a survey carried out from 1949 to 1950 in waters of lower latitude, we confirmed that the distribution of larval and young swordfish as well as adult swordfish containing matured • ovaries was found in the region of waters between the northern limit of 26 °N. Lat. near the Marcus Island the Equator. In the same years, we have also caught larval swordfiSh from the coast of the Ryu kyu Island. From these results, the vast area of waters including the southern Black Current and the southern Pacific Region south of the Subtropical Convergence, which was regarded as a worthless fishing ground for swordfish, was now predicted as a particularly Useful area for spawning as well as growth of the particular fish, while the northern area was regarded as the fishing ground for grown swordfish which were trying to find foods. We also carried out surveys on the sea every year after 1951 in the West Pacific Ocean • in mainly southern waters from 30 °N. Lat. paying special - 54 -

• attention to the following matters in'collecting samples, especially swordfish: 1) the genital glands, particularly examination for maturity of ovaries, 2) collection of larval

swordfish, and 3) collection of young swordfish from the stomach contents of predators, such as tunas and marlins. 129 Table 6 shows data of the above survey on an annual basis. As the table indicates, among the swordfish captured from the Pacific Ocean there were only 5 samples* had mature ovaries out of 372 swordfish examined during the past 9 years. [This number did not include the samples which were transferred to other laboratories for the investigation on a request basis.] The reason for such a low number of swordfish • possessing mature ovaries in the waters of the lower latitude (North Pacific area) seemed to be that sexually immature young swordfish were predominant and large forms of swordfish were few in this region. On the other hand, the reason for the low number of larval swordfish captured would be that the fishing method by surface pulling with the larval-net described in the section 2 could make it difficult to catch sush fish effectively. The number of young swordfish obtained from the stomach contents of tunas or marlins was much higher than the number of mature swordfish or that of larval swordfish. Black marlin was usually the predominant one containing such swordfish in its . stomach contents. The • first reason in this regard would be that the number of -55- • black marlins examined were high, but it could not be ingnored that a higher rate of finding young swordfish resulted when black marlins rather than striped marlins or white marlins were examined (Watanabe, 1958). b. Egg-diame'ter ditribution of mature ovary eggs In June, 1954, a mature ovary was obtained from a swordfish of 186cmee in body length and 8.5 kg in ovary weight which was captured during the survey trip by the Miyasakimaru ship in the Satsunan Coast. A part of the ovary was fixed with 10% formalin. [Body length indicated in this Chapter denotes the length between the posterior edge of the eye and the tip of the central ray of the caudal fin (eye-folk length) unless specified. The correlation • between body length described in the previous section (Body length in Appendix 2) is approximately as follows: body length above 100 cm, Y = 1,087x; body length 30-100 cm, Y =

1,045x + 3.9; body length below 30 cm, Y = 1.20x; Y = eye->folk fin length; X = body length.] The ovary specimen was merely a mass of ovary tissues and the detailed structures were not clear. Figure 18 shows the distribution of egg diameter frequencies on total egg (larger than 0.2 mm) included in 0.5 g of a block of nearly matured ovaries which was prepared after taking out the contents of the tissue mass. The total egg number was 835. The eggs were divided into 3 distinctive groups: 0.5 mm or smaller (I group), 0.5 to 1.2 mm (II group), and 1.2 to 1.6 mm • (II r group). The number of spawning times in a spawning period - 56 -

• was not clear as to once or many times of spawning accdrding to the figure. At any event, the III group was considered as from a single spawning. From such considerations, the ratio of the III group to the total egg number used in Fig. 18 was 24%, thereby the quantity of one spawning would be approximately 3 to 4 million. C. Relationship between body length and ovary weight 131 This relation strongly reflects the situations of maturing of each group of swordfish. Figure 19 shows the body length - ovary weight relation of swordfish obtained from --he North Pacific fishing grounds (northward from 30 °N. Lat.). The swordfish possessing over 1 kg of ovary obtained in these region were generally large swordfish whose body • length was more than 200 cm regardless of the waters irited such as the coast of the Sea of Japan (northward from 30 °N. o 140 o-150 E....a) or the East Offshore (northward from 30 N. o o 160 E-150 E...b). According to Fig. 19, there was almost no difference in maturing between the coast and the offshore. The seasonal changes in ovary weight found in the group of sworffish obtained from the Coast are shown in the figure* and no development occurrred in the maturing stages through- out the period of seasonal migration into the southern region. [Fig. 19 is similar to the body length - ovary weight relation of the swordfish obtained during the period from December to April on the coast of the Sea of Japan reported • by Kubo and Kajita in 1958.] -57- • However, the relation between the body length and ovary weight in the swordfish obtained from the spawning area of the broader region is shown in Fig. 20**. [**This figure includes some swordfish belonging to the group which migrated into the south from the fishing ground of the North Pacific Ocean. This is simply duato the conventional division of the North Pacific Ocean at 30 °N.] Since the cases involving measurement of matured ovaries in swordfish obtained from only the North Pacific Ocean were too few, materials obtained from the Indian Ocean were also added to this group. If body length was under 130 mm, the weight of ovaries was under 200 g, which seemed to be an immature situation even though swordfish lived in the spawning area. A scattering phenomenon in ovary weight distributions was found when body weight increased to more than 140 cm. Thereafter, the situation in this regard is shown in the figure. The dotted line in the figure shows that the upper limit of scattering is in a trend of increase. This was a hypothetical line but the figure shows a change in curvature between 150 cm and 170 cm of body length. Thus, the curve would be of an S type. It was, therefore, predicted that most swordfish were maturing sexually in the region from 150 cm to 170 cm in body length***. - [***Since there were no specimens to be measured on the materials obtained from the Indian Ocean, the maturing stages regarding ovaries of 3 - 5 kg shown in the • figure were not confirmed.] - 58 -

d. Distribution of matured and young swordfish Swordfish possessing ovary weights ranging over 3 kg, which was considered to be in a reasonably matured state, were captured from the broader area as shown in Fig. 21. When the figure was combined with figure for locations of larval fish captured, the ranges of both distributions completely matched each other. Therefore, predictions made so far in regard to the area for spawning were supported by these observations. In the area of the Satsunan Sea, larval swordfish were captured from te arc-shaped area from the south of Kyushu through the west side of the Ryukyu Islands to the Luzon Islands. However, the view that the spawning area was limited in the southernarea of the Black Current might be too quick a judgement. There seemed to be a possibility that the spawning area would be extended further eastward referring to the locations of matured swordfish captured. In the West Pacific Ocean located eastward from 140 0E, matured or young swordfish not seen in the area located northward from the Subtropical Convergence, but were distributed in the area located southward from it. From the results of the survey done in the North Atlantic Ocean, A.V. Taning (21) reported that larval swordfish were captured from the area where surface temperature was at or above 24 °C but it was clear that the Subtropical Convergence could play an important role in distribution of matured or larval • swordfish in the West Pacific Ocean. - 59 -

17-) The matured ovary of the swordfish was also obtained from the northern part of Coral Sea in October and the area of the Fiji Islands in June*. [*No measurement of ovary weight was done since the maturity was determined by visual observations.] This may indicate that the spawning place of swordfish could also be distributed in the South Pacific Ocean.

The young swordfish obtained form the stomach contents of tunas or marlins were about 10 to 30 cm** in body length, or were in the early stage of the young swordfish period, and they did not have strong swimming power. [ **Body length.] Their appearing zones are shown in Fig. • 22***. [***Materials related to the waters southward from Hawaii were obtained from the survey done by the Pacific Oceanic Fishery Investigation in Hawaii.] The area where young swordfish appeared was a lower latitude zone of (as far as the Pacific Ocean area was concerned****) of subtropical and tropical waters from 25 °N. to the Equator. f****In the Indian Ocean, young swordfish also appeared in the lower latitude area near the Equator. The Najimaru Survey Report - see reference No. 2.] Locations for young swordfish obtained may be the capturing place of the predator whose stomach contents were examined. However, the distribution range for young swordfish was about the same as that of larval or • mature swordfish. Young swordfish were not available from 60 • the area of the Ryukyu Islands. This was probably due to the lack of a survey for stomach contents of swordfish in the particular area. No young swordfish were obtained from the higher latitude area in both the Indian and Pacific Oceans although surveys were carried out time to time. From these results, it was predicted that there was no distribution of smaller fish than that of the young stage in the high latitude area, northward from 30 °N. The swordfish in the late young stage of growth (30-60 cm)***** were distributed in th s: Tropical and Subtropical zones, and they were swimming around in gradually further higher latitude areas as their growth proceeded******. [*****Body length.] [******Swordfish • in the late young stage were also captured in the area northward from 30 °N.] Southward from the Subtropical Convergence within the North Pacific Ocean is a spawning area as well as a zone for growth of young swordfish. This young swordfish group seemed to be the preparatory supply group for the adult fish group which would form the fishing ground for swordfish in the North Pacific Ocean. Detailed discussions 133 on the South Pacific Ocean in regard to swordfish are unavail- able at this time since materials obtained are partial and limited. However, the possibility of spawning was predicted, whereby the young swordfish group in this zone could be the supply group for the adult swordfish group distributed in • the coast of New Zealand and the South-east coast of Australia. 61 - • e. Spawning season

Table 7 shows the numbers of matured ovaries,

larval - and young swordfish* collected per month. [*Please note that numbers indicated in this table are not the percent of unit effort.] To discuss on spawning season, it was necessary to divide the total spawning areas into several proper zones because the spawning areas were spread over exceeding broad spheres. From the point of view of the survey, the North Pacific Ocean was divided into 3 zone of water-i along with the South Pacific Ocean including the Coral Sea and the region eastward from 180 °E. The Indian Ocean was regarded as one combined zone. There were some • cases of ovary findings from the Bay of Bengal as well as the east - and west parts of the Indian Ocean (refer to Fig. 21). The larval swordfish from the area of 1°-2° S., northward from the Solomon Islands, were included under the name of fishing ground in the North Pacific Ocean. According to the table, matured ovaries were obtained in June from the area in the West Pacific Ocean

(Westward from 140 °E.), or the area of the South Black Current, but larval swordfish were obtained in March and May from the coasts of the Luzon Islands and Ryukyu Islands, as well as in August from the southward of Kyushu. Therefore, spawning seasons were predicted as a half year period from • February or March to July or August. Thus there would be - 62 -

very little chance for spawning during» the period from autumn to winter. From the North Pacific Ocean particularly o o o o in the spheres of 15 -30 N. and 140 -170 E., matured ovaries was obtained in April and May, larval swordfish were caught

in May and June, and young swordfish were obtained in February, May, June, and July. A young swordfish was obtained in February but the major spawning season of the region seemed to be the period from March to June. Although the survey was not done in September and October, it was presumed that

the major spawning activities might not happen during the period from autumn to winter. From the southmost area of

the North Pacific Ocean which is one of the 3 divided areas of the North Pacific Ocean (namely the area of 15 °N..-

2 ° S.), a mature ovary was obtained oncein October from the o area of 135 W. in the eastern part of the Pacific Ocean. There were no captures of matured swordfish from the area

between the Parao and Marshall Islands which were the major survey zones in the southmost area of the North Pacific region.

However, larval swordfish were obtained during the period from June to November, and young swordfish were caught in the period from May to November. In this region, therefore, the spawning

season seemed to be the period from May to November. This region was the only place in the North Pacific Ocean where

the spawning cases were found in autumn. However, it was 134 • with regret that no consideration for the spawning season was - 63 -

• available at this time due to the lack'of survey data during the period of January to April. It was recognized that there would be a peak spawning period during the spawning season in each area described above. However, spawning may last for a

long period'if it was considered on the basis of the entire

area of the North Pacific Ocean. Thus, there would be the possibility of whole year round spawning in the North Pacific Ocean if the areas of lower latitude were also included.

In the area of the South Pacific Ocean, it was pre-

dicted from the various sources collected that spawning activities could occur in October in the northern area of the Coral Sea and in June in the area of the Fiji Islands. However, detailed

descussions on the spawning season in this region were one of • difficult tasks because the materials obtained were only partial and limited in number. Substantially matured ovaries were obtained in April from the Indian Ocean, particulary the area between the Equator

and the Bay of Bengal. From this region only immatured ovaries

were obtained in March, therefore, the spawning season would be after April*. [*During the survey of the South Indian Ocean

(20 °-22 °S., 49-53 °E.) done in 1958, 6 young swordfish were obtained from the stomach contents; 2 in August, 3 in November and 1 in December.] - 64 -

• VI Growth

a. Growth of young swordfish

To date no detailed discussions on the growth of young swordfish were available. Based on the records made by Arata (1) and the DANA Report, A.V. Taning (21) predicted as follows on the growth rate of the young swordfish obtained from the Indian Ocean: according to the distribution of the monthly

body length of the larval swordfish, 8 mm in body length during March :Ind Api',i1 changed to approximately 23 mm in July, and then to about 70 mm in the next spring. Therefore, the fish averaging

70 mm (the range of body length was 50-80 mm.) would be one year

old and the fish of 192 mm reported by Arata should be 2 years

old. However, there may arise a question that such growth rate might be too slow for an active fish possessing such a giant 136 body. This kind of speculation was also made by Taning himself. The values, regarded as too low, seemed to be due to ignoring the width of the waters where sample fish were taken when Taning

determined the growth rate of the larval swordfish. If such a vast area of the North Pacific Ocean were made en bloc according

to his method, the body length* distribution of the young sword- fish obtained each month would be as shown in Table 8. The

finding of the growth rate was rather difficult from Table 8.

As described above, the spawning season was presumed from April to October on the basis of the entire North Pacific Ocean. * Hereafter the body length denotes the interval between the eye and the folk fin as described in the previous chapter. - 65 -

However, there were some considerable differences among the divided regions, if the North Pacific Ocean was divided into several regions. Therefore, an ignoring of these facts seemed to be the major reason for difficulty in resolution of the spawning season. Table 9 shows the average body length on a monthly basis when the North Pacific Ocean was sub-divided into two regions, the Marcus Island region and the Caroline-Marshall Islands region. The growth situation for young swordfish could be estimated from the degree of increase in average body length during the period from May - July in the area of the central latitude, on the Marcu-s Island region (18 o-24 °N,. 148 ° -154 ° I) except the region of the South Sea Islands; this covered a vast area from the east to the west. The distribution of the monthly body length for this region is shown in Fig. 23. The spawning season for the Marcus Island region may be estimated as the period from approximately March to June. If the change in distribution of body length was taken into consideration, the growth of a group of swordfish that developed during a certain period would be readily comprehensible. However, the materials used here were obtained from the stomach contents of predators after the swordfish were eaten as their natural- diet (prey). Therefore, the following problems were to be considered:

1) Since the young swordfish were obtained from the stomach of predators, the range of their body length was in certain limit, thereby the range might not fully re flect from the natural state. - 66 -

•• 2) The distribution of body lengLh of young swordfish might be influenced by the size of predator or the difference in kinds of predators. The above case 1) was especially a problem here because the range of body length (maximum and minimum length) of most young swordfish eaten as the natural diets of predators was similar to the body range found during the period from May to July as shown in Fig. 23. The range of length of young swordfish obtained from the region of Marcus Island as well as the entire North Pacific Ocean was approximately 9-39 cm in body length. Therefore, if this range was similar to that of the young sword- fish used as the natural diet of tunas or marlins, it would be a problem whether the change shown in Fig. 23 was considered as the result of growth or not. The range of body length described above was based on only the samples obtained from the North Pacific Ocean, which were measured by us. Therefore, there was no guarantee that no one exceeded the range limits among the specimens which were not affected as to the size of the original body by the predators digestive action. In fact, if the region of the South Pacific Ocean was included, the estimated body length of young swordfish obtained so far was approximately 60 cm in maximum length, followed by one each of 45 cm and 43 cm. Therefore, one could say that the limit of body length of young swordfish in terms of a natural diet of predators would be approxi- mately 10 cm minimally and 60 cm maximally. However, the previous question which had arisen with regard to Fig. 23 may still remain to be solved even though such a view was applied. • - 67 - With regard to case 2), in order to find the effect of the size of predator on the distribution of body length of young swordfish, the correlation of body length between both predator and young swordfish was firstly studied on with case of the black marlin because black marlin was found to be the major predating specimen. The results are shown in Table 10. According to the table, the distribution of body length of young swordfish seemed to be not substantially affected by the size of the predators. In this case, the correlation coefficient was about 0.24. The kinds of predator were secondly studied. 137 In the North Pacific Ocean, young swordfish have been obtained so far from the stomachs of the following 10 predators; black marlin, sail fish, yellowfin, albacone, , striped marlin, white marlin, short-nosed spearfish, bigeye, and blue shark. Among these predators, the black marlin was the predominant one, for example 155 young swordfish (76%) were obtained from black marlins out of a total of 204 young swordfish obtained from the above 10 kinds of predators' stomachs. Also 52 (74%) out of total samples of 70 young swordfish used here were obtained from the stomachs of black marlins. Figure 24 shows the number of specimens of young swordfish obtained from predators. As shown in figure, most specimens were obtained from black marlins, therefore, the effect of other kinds of predators on the distribution of body length in young swordfish could be almost negligible. • - 68 -

• The above considerations comprised the area of concern with regard to body length distribution for young swordfish. Although there were some problems, no other significant negative

factors would be involved in assessing the results of Fig. 23 with regard to the growth of young swordfish. If there were no significant objections in recognizing the average monthly increase of body length as the growth period during the 3 months described above, the growth rate was much faster

than that in the case of Taning's estimation of growth of the young swordfish. This also indicated that the period for estimation of growth in young swordfish could be at most 3 months using the distribution of body length of young • swordfish obtained from the stomach contents of predators, but a longer period than 3 months would be suffered for estimation of growth by the limit of body length for natural prey.

b. Growth curve 138

Figures 25 shows the body-length compositions of o swordfish from the North Pacific fishing grounds ( . 1 140 -160 which was known as grounds for swordfish during an eight-year period from 1948 to 1956. The survey period was from November to March every year, and each curve of every year was nearly the same showing a single peak. As for the body-length compositions, the modal states of older group at the right side of peak were combined with each other. - 69 -

• In contrast, the modal states of the younder group at the left side of the peak showed several small peaks. Among these smaller groups of peaks, 4 peaks appeared at the same

location every year (a, b, c, and d) and these peaks were found near 73, 102, 128, and 148 cm respectively. However, in 1951 (November 1951 to March 1952), the peak of body- length composition was found near 138 cm. This case gave the only one additional peak to the 4 peaks described above. Table 11 shows the locations of the annual progression of modes for the 4 younger groups described above. The line of each system in the table shows the growth state of each group under the assumption that each mode had one year difference. The lines in Fig. 26 were obtained by ploting the values of 139 each system. In this case, every value was on the straight line, whereby each of the 4 modes seemed to show the group of development which had the same difference in the length of intervals among them. Following is the discussion on the trend of growth under the assumption of one year difference between the modes on the body length compositions. As already discussed above, if changes in terms of

monthiyaverage body length found in the region of Marcus

Island in Teny - July (or the change like 17.1 cm ÷ 25.1 cm

30.1 cm) showed the changes of the development group, the development time of this group was estimated as the period of March - April. This was predicted from the growth rate • of the young swordfish but it was also matched by the spawning season in the region of Marcus Island. 70

• Thus, the aVerage body length in May was approximately 17 cm, and it was assumed to be reached within 1 or 2 months after the inititation of development. For convenience, if body length reached 17 cm after one month from a certain point of development, the trend of growth occurring for 2 months thereafter will be shown in the straight line of a logarithmic graph. A straight line was drawn by

body length versus such growth trend (see Fig. 27). On the other hand, the point of the mode of the youngest group (group a) from the body-length compositions of swordfish captured shows approximately 74 cm. If this point were taken on the extrapolation of the straight line

described above, age would be about 16.5 months*. [ *It was • calculated by the following equation: y = 0.52 x 1.236; X and Y denote age in month and body length of young sword- fish in logs. respectively.] The point of each mode of the other 3 groups (b, c, and d groups) averaged 102, 128, and

148 cm respectively. If these points were plotted at 12 months intervals on the basis of the original point of 74 cm (16.5 months) described above, another straight line of slightly different shape would be obtained. (see Fig. 27). Many reasons might be involved in this case resulting in 2 different slopes, but the difference seemed to show the change in growth rate occurring during the body growth period from 30 cm of body length. Therefore, the size of the youngest group in terms of - 71 -

• •• body-length of the swordfish, or the point of 16.5 months obtained from the point of 74 cm in average body length would be slightly changed due to the change of the growth rate occurring during the period. If the change in the growth rate was not dramatic, the general growth trend of the 140 swordfish could be determined by combining the two straight lines described in the figure. The growth curve drawn under such a premise is shown in Fig. 28. The age in months shown in the figure is represented under the assumption that the development period of the young swordfish is 3 months. The curve shown in the figure may show only the general trend of growth to the extent considered from present materials, but • the following matters with regard to the age of the swordfish may also be estimated:

1) Swordfish generally attains a length of about 50-60 cm during 1 year after its development.

2) The age of the first spawning time, or the youngest adult described in the previous chapter is approximately 5-6 years old.

3) Swordfish taken commercially in the North Pacific fishing grounds are approximately 2 years of age and older, and the predominant age group consists of 4 to 5-year olds although there are some one year olds from the young group. - 72 -

• VII Feeclinp; habits Arata (1) discussed feeds stating that was for swordfish in the early larval stage and various pelagic larvae of fish in the surface layer of the waters were for swordfish in the larval stage. These observations agreed with our survey results (refer to the section of the larval swordfish stage described above). The stomach contents of swordfish in the young stage, as shown in Table 12, were mainly and various fish although there were also some pelagic crustaceans like amphipoda. Of the fish, Echenedae, Balistidae, Lepidotidae, Acinaceidase, etc. were found in the stomach contents. Therefore, the fish found in the • .stomach contents of swordfish in the young stage were not limited to the fish living in the surface layer of the waters. • The stomach contents* of adult swordfish (also including immature swordfish) were also occupied by mainly

squids and (the appearance rate of squids was over 50%**), and by negligible numbers of pelagic crustaceans. [*The stomach contents of adult swordfish were surveyed in o o the area of the West Pacific Ocean, 20-40 N. Lat., 140 E.- o 180 Long.] [**The values indicates the ratio of percent of the numbers of swordfish which preyed upon squids to the total numbers of swordfish surveyed.] Of other fishes, Lepidotidae, Acinaceidae, Pteraclacidae, Alepisauridae, - 73 -

Mycototphidae, Sternoptychidae, Katsuwonidàe, etc. were found. As preveiously mentioned in IV, an increase in swimming capacity of swordfish due to dramatic development and morphological changes, especially the caudal part (the caudal vertebrae and the caudal fin), during the period from the final young stage to the immature stage seemed to affect the kind of fish preyed upon; in addition, situations for different fish appeared in connection with the enlargement of the vertical and horizontal dimensions of their hurrUng

grounds. Summary

. The present paper deals with the life history of swordfish, Xiphiai gladitm Linn., on the bases of the materials taken in the North Pacific, the South Pacific and the Indian Ocean during 1947 to 193s. • 2. The distribution of swordfish ranges over the wide areas of the temperate and tropical zones, with its main fishing grounds only in the temperate zones. In watets near Japan they are fished extensively from autumn to late spring in the regiol. of 140 Long. and 45°•---,28°N. Lat., the so.called Nortl.. Pacific fishing grotu,As which lie between the Po ler Front and the Subtroal Convergence. . 3. Measurements, descriptions and illustrations wete made on 26 larvae (total length 4. Omm.) by the larva-net and the dip-net, 36 youngs (total length 160— 570mm.) from the stomachs of tunas and marlins, and 6 youngs (total length 570 — 1300mm.) caught by the longline. There are • other 250 youngs insufficient for the description which have been collected from the stomachs through the course of our study. 4. Observations and measurements were made on the ripe ovarian ova preserved in 10 9e•fortnalin after holding in sea water for a while The ova are truely spherical, ranging 1.50 œ 1.68mtn. in diameter. Egg, membrane is colourless and translucent, with a faint melon-like network over its surface. Yolk becomes fixed and %vitae. Embedded in the yoll; is a single pale-yellow oil globule, which is about 1/1,-4/5 the ova diameter. The ova are subject to the perivitelline space. In these all respects the swordfish ova are considered to be buoyant in sea water. 5. In the North Pacific Ocean the fish with ripe ovaries, the larvae and the youngs are widel • distributed over the areas from the Subtropical Convergence to the equator , . whereas no sperimens' have been collected from further north. In the South Pacific the larvae and youngs were taken near the equator, the ripe ovary, larvae and youngs being taken in the Coral Sen, and the ripe ovary and youngs beng taken near the Fiji Islands• In the Indian Ocean the ripe ovary were taken near and north of the equator. The youngs being taken near the equator and about 20°S. Lat. There are no other samples and specimens collected from the sea of higher latitude than about 20°S. Lat. . It is believed to us that the swordfish breeds over lower latitude areas of these •oceans which mentioned above• 6. In the mid latitude area of the Norill Pacific, spawning season can be presumed to be from February to August, especially the most prosperous season is front march through June. In the equatorial ztrea spawning might be effected the year round• 7. Growth and development of various body parts are discussed and illustrated with graphs. According to the change of body form, metamorphosis of intestine, and the process of the scaling etc., five stages of development are suggested . as follows. (body le ng th is tile distance front the posterior end of the upper jaw to the end of .the hypural bone) (I ) Larval stage (bod ) length is under ca. 100nint.) spinnus processes on head appenr a ni devehip in this stage and disappear at the end of this stage. Spinous scales develop nt most and are obvious in this stage. Dorsal fin and anal fin are high through the entire base :the' the tendency to separate into two parts can not be recognized yet. Snout is stout at the beginning but rapidly lengthens and becomes very slender. (Figs. 3--8) (2) Pre-yotmg stage (body length 100--.300mtn.) Spinous scales begin to degenerate, but still obviously rentain. Dorsal fin and anal fin are recognized to have the tendency to form anterior lobe, yet the fin-rays of the central portion are the highest. Caudal fin begins to fark. Snotd is relatively shorter than in the larval stage and widens breadth. Snout extension (the distance front tip of snout to tip of mandible) is slightly bigger thaa that of the larval stage, but it • s still a little. (Figs. 12--17) 0 Post-young stage (body length 300 ---,GOOmm.) Degenerating of spinous scales advance and scales become traeeable. Formation of anterior lobe in both dorsal and anal fins proceeds and the tendency to divide into two parts in both fins can be recognized. Caudal fin becotnes forked. Early in this stage lateral keel of caudal peduncle is formed and barring patterns of the body disappear. In this stage intestine forming folds from simple tubular form in the previous stage, becomes zigzag pattern. Snout grows in length rather than in breadth. Snout exten- sion rapidly increases and grow's nearly to the adult one. (Figs. 11-17) (4) Immature stage (body length .600,,1400mm.) At about 600mm. in body length both dorsal and anal fins bein.z divided into UY0 parts, nearly . beconte the adult form, and the caudal fin becornes distinctly forked.

(5) Adult stage (body length over 1400mm.) (Fig. 17) • 8. From the growth curve figured by combining the seasonal increment of the.ave- rage body length of the young and the annual progression of modes on the body length compositions of the longlinc catches, the follov/ing matters may be mentitined : . Generally the swordfish attains the length of 50,,30cm. in the first'year, 80,40cm in the second Year and 100,,12acm. in the third year. (body length isthe distance from of the center rays of the tail) the posterior margin 9. The swordfish taken commercially in the North Pacific fishing grounds are those of about 2 year of age and older,' the predotninant age group being 4 or 5-year old. It is assunted that the swordfish begins to migrate to this area north of the Subtropical Convergence Mten they attain the stage of 'the post-young' or 'the intntature' in the breeding areas. 10. The biological minimum can be asSunted to be 1507-170cm. in bodY length. (5 or old) . (body length' is saMe as mentioned-8) 6-year 11. From their stomach contents we can say that in their larval stage swordfish feeds on zeoplankton, pelagic larvae of fishes etc., in their yotnig stage mainly feeds on squids nnd fishes, also catching pelagic crustaceans like amphipoda. In adtdt, squids occupy the greater part of their stontach contents, fishes next and crustaceans are little found.

- 76 - 143

e• te

1. ARATA, G. F., JR. (1951) A contribution to the Ife history of the swordfish. Xiphias gladius Linnaeus. • from the sotttlt coast of the United States and the Gulf of Mexico. Bull. Mar. Sci., Gulf and Caribbean, 4 (3), 183-243.

2. #12[Iiiii1 — fik, (1958) XiPhias giadius Kiï:"!fl: No. 51 3. GOODE, C. 13. (1883), Materials for a history of the swordfish. Rept. U. S. Comm. Fish and Fish. for 1880, 289.394. 4. GREGORY, \V. K., And G. M. CONRAD, (1937), The comparative osteology of the swordfish (Xiphias) and the sailfish (litiophoects). Amer. Mus. Nova., (932).

5. •01111A (1957), ) k X. gladius LINNAEUS O111: - .)1.‘1.-- , ii128 er) 6. i, 1111 (1942) . 7 ur • jJ ir

7. ;l:/111f(112. (1954). -7 7t1 1LVa 3r• già 1111T1127 4F- allk (1 )1 e *rem 8. (4111). r/ Jtek). fril.T4133 9. LAMONTE, F. R. (19-!4),Note on breeding grounds of blue marlin and swordfish off Cuba. Copeia, 1944, (4), 238. 10. LAMONTE, F. R. (1958), On the biology of the Atlantic marlins, Makaira ampla (Poey) and Mr:kaira aThida (Poey), IluIl. Anieri. Museum Nat. Ilist., 114 (5), pp. 396-401. 11. LEE, R. E. (1942), The occurrence of female swordfish in southern New England waters, with a description of their reproductive condition. Copeia, 1942 (2). 12. LÜTKEN, CHR. (1880), Spolia Atlantica. Bidrag til Kundskab om Formforanclringer • hos Fiske under (lures Vocxt og Lidvikling, soerligt hos nogle af Atlanterhavets Hojsofiske. Vidensk. Selsk. Skr. (5), 12, 441-447. 13. tile:A:ill (1936) (11. 12), 19l192- 14. NAKAMURA, H. et al., (1951), Notes on the life history of the swordfir.11, Xiphias gladius Linnaeus. Japanese J. Ichtliyol. 1 (4)', 264-271. 15. rie- (1958).*Âlirlii11;1z:et -jZ) Fle.11. 24 (15), 322"-'325. 16. SUEUIRO, Y. (19 11), A stttdy on the digestive systein and feeding habits of fish, Jap. Jour. Zool. 10 (1), pp. 1,--,303, figs. 1.-190. pis. 1.-45. 17. SANZO, L. (1922), Uova e larve di .XiPhias gladius L. Mem. R. Com . Talassograf. Ital., 79, 1-17. 18. SANZO, L. (1930), Giovalissimo stadio larvale di ..Yiphias gladius L. di min. 6,4. Mem. R. Com . Talassograf. Ital., 170, 1-8. * • 19. SCHMIDT, JODS. (1912), Introduction. Rept. Danish Ocean. .F.',xped., 1908.-1910, to the Mediterranean and adj. Seas, 1, 1-49. 20. SELLA, M. (1911), Contributo alla conoscenza della riprocluzione c dello sviluppo del Pesca-Spacla (Xiphias glarlius L.). Men'. R. Cont. Talassograf. Ital., 2, 1-16. 21. l'AN1NG, A. V. (1955). On the breeding areas of the swordfish (Xiphias), Papers in and Oceanography . Suppl. to vol. 3, Deep-Sea Research, pp. 438-450.

22. ni ii:l1.11 (1958). i'lirdU 31;e.A.;:tiliiii/Mcle I) Z) 1 .23. x;‘,5 yyjiy4- Xiphias g1arlius 1 (4), 260-263. • 21. ;11 lq (1953) X1n fl'S 2 i)(ifiilt -e u Wit} ›C le k einpi i11), iïï 1 I.>. ntlf 25 -U.

• -••••.. e • •'•', • • • • - 77 -

2. S. Enota (1958) Studies on the young swordfish ( Xiphias gladius ) collected from the lower latitude region of the Indian Ocean. The Tuna Fishing No. 51. 5. Y. Kubo and K. Kajita (1957) Studies on the swordfish ovaries (X. gladius LINNAEUS ). The Research Report of the Ibaragi Fisheries Research Station -(1953). 6. K. Kimura (1942) The fishing state of the tuna and swordfish. The fishing state of the major fishes in the mainland (Vol. 2). Suisan Seizo Kogaku Koza ( The Series of the Processing Technology for Marine Products ) 7. s. Kigawa (1954) The annual fishery state of the tuna fishing - 1952 issue for swordfish. Edited by the Southern Regional Fisheries Research Laboratory. 110 8. S. Kigawa (in press) The annual fishery state of the tuna fishing - 1958 issue for swordfish. Edited by the Southern Regional Fisheries Research Laboratory.

13. H. Nakamura (1936) Yoshoku Kaishi, 5 (11, 12), 191 - 192.

15. S. Nakakomi (1958) The fishery state of swordfish in the Northwestern Pacific Ocean, and the body length variations, distributions, and swimming

area of the swordfish. Nissuishi (Journal of Japanese Fisheries Society) 24 (15) 322 - 325. 22. H. Watanabe (1958) Differences in the diet compositions of the striped marlins and white marlins in thee-Equator Region the Western Pacific Ocean. The Research Report of the Southern Regional Yisheries Research Laboratory.

The 7th issue 72-81. • 23. H. Yabe (1951) The larval swordfish (X. gladius). Gyoruigaku Zasshi

(Journal of Fishery Science) 1 (4) 260 - 263. - 78 -

24. H. Yabe.(1953) The larvai swordfishes collected by the second survey using the Amataka-maru boat for the tuna resources studies (preliminary

report). Nankaiku Suiken Gyosekishu (The Records of the Project Activities, the Southern Regional risheries Research Laboratory) Vol. 1, Activity - No. 25.

- 79 -

. E 1 7 0' 5 1 II 0' 1 *. W • 110.5 150• 1O 1302 1.70 • N 50'11

4

• •••') P ..e..et s ,10 70'11 a- . . . .1,.. e 4. .t• :e.,...,...... ,,,,, 40' -Z. ./•''' ..,,,.., ,,•;.',:z. .•••• . •••e., ,.....•++;-,,1 ,0.••••!;,..7ee•-•, •••••••::••.«.;ti,•“..eL•,• ..: 1 , p I _ f i i ,• :' i°, .". /".."•"''''"'" ''''"'..."...... tiel ,,••• 4.."`;;;‘,. à•;•,17:.'" :W. ••••••Z''',7.r.7 ::: ›,...... ...51 - • .. - • 1- ,,,,,,,,,,,,,,r/f7i7/717,77-,„•-"'''-'':-=7.-•,;' • 4,,•• , e • , 44.7 ,...< '2'3 . ,,,,e.e.rr,•_2.,e2.-7rern,e,rre.,177Ye.7 e.'I.,,7k ie-rereeera,m7 rP.77r•.•7,,•774 .. " -- ..i. • '...?, itiffil:/47e7e7. .e.„....077..,,e..ift....t.r.t...,7477,47,1 .."%74,...,,,,, 1^, . -'1 ,e, '.... ' e"..7.1-•.:1 (%.4› '''''' '''',•%77,71 le.,,,.... • 4,4 r.* • 11_,‘. ..•ei' . 1›,...,,,,, ,,e• ... 4'''''' ,.••7.1,1,.....,, ,,;-;:e‘7,,,,,,,,,,,,,,.... 1 ''''''',.... 1,frue - T te' • ,e--, ., . . , .-,kilee --'4-,,, -.. - .--> 7.;1- -' là1,7.e (i; l'Is.„.,„.•::: .n•; ,ï 4 ...... , ,-.4*,,,--_, ,,...7. ..„..„,---:„...47.1- 30•04 %.,F..1,77 24 I '7'5.* .e...--;‘,..„7.74 • . 7.4-=e.r...._ 3 0' 11 - - elti! ' ,;3.0.1;.7:471- 47. ,,'"_ree'''''''' 2 , • • «‘• 1zie 4. -4444--3- i .*-. I .-e4''''' fa .'••••,•72-7b e -.' - _. 44r

20' w 8 11" 1•1 1 7 0 • 1 • 174' w 130'2 1 0'5 1505 1 II'

0fJC-/j] ejr5T;--3-. 0 grounds). (Fig. I Seasonal southward movement of swordfish fishing * Numbers described in the various fishing grounds denote the months. • ** The line of the bubtropical Convergence. 90 100 110 120 130 140 150 160 170 180 170 •

50 t . 50 t .• • • 40 40

5 1, 1 ej 30 I e 0 . 0 e . •

2 7414. dill 20 le 0 0

(1 13q 0 0 00 P% 10 e c • 5, .1 r> e* •• t • e 0 0 a •. O c• 4 % ' MO .. eZ) o e tj t. 7. .7 4e4 0 p . 17 ,b, 'C ' .> ..' ' • 1 t, o 0 0 .7 b . ..„ , c... Y1, 20 90 100 110 120 130 14 0 150 160 «ill 2 M e ilÉ 14 es . •n- • (Fig. 2 Areas of capture of larval swordfish.) • - 80 -

* Total length

Fig. 3 e,1 5.1mm

Fig. 4 Jj 6.4mm

• Fig. 5 8.2mm.

Fig. 6 r< 11.0mm

Fig.? 27.4mm

• Fig. 8 ±14. 73.0mm

Fig. 9 ±J 204mm — 81 — •

.ie

M10E4 A« 0 AV iffl 121 (C2g9 Fig. 10 Ventral view of the viscera, in situ.(specimen No. 9) 1 - Liver ; c - Caecal mass ; s - Stomach ; I - Intestine ; r - Rectum

11r.-1 ei re 0 AV Trii bzi ( 28) Fig. 11 Ventral view of the viscera, in situ. (specimen No. 28)

82 11•111

• 90 • • • g • . . • • I. •• • • • • • — 70 • . • •• ••• • • t • • • ••• • • x • ' • . .. e 01- • •• 60 to • : X • es . . w50 • • -J

030 1-40 [ v) 201- 101-

I Élitt 2 3 4 10 2 3 4 100 3 4 1000 Body length (mm) re12M ei 41-1 m- F.,. Fig. 12 9,1 Of snout length against body length. Dots represent study specimens; X's, S. Nakamura's sp.ecimens.

90

r•• •• • • • • , • 01- 60 • U150 -J • • 340 e • ••• :a• e •e • ct 30 •e 20 • •.• 10

O 1R if 1 I 111111 I‘ 2 3 4 10 2 3 •1 100 2 3 4 1000 2 3 Body length (mm) . T ct 14 0 411 e • Fig. 13 % of lower jaw length against body. length.

/1 • • 4.0 • • 3.5 5.0 2,5 Ob 20 • • • • • b • a, • • •• 10

2 3 2 3 4 10 2 ; 4 100 2 3 4 1000

Body length (min) ifstel .FW1:.:;11 tei rec m lc er e it Fig. 14 Ratio of upper jaw length to lower jaw length in relatioli to body length. • - 83 - 4 16 14 12 • \

8 • • X X 6 : • 4 • • ir •• O .* •• .• jet% ••

...,..t 1_1_1 1 1111 1 1 11.1%1 2 3 4 10 2 3 4 . 100 2 5 4 1000 2 5

• Body length (mm) el5M ri.brivitzeom (%) 0eRicis5eit Fig. 15 % of snout width to snout length and snout width to body length in relation to body length. X 5,4 of snout width to snout length. C) % of snout width to body length. 0. 0 Nakamura's specimen

m55

6 •. 2 3D • • •-• ttl • % 25 % •• • • • • • • • cc< 20 • • •• • 1- 15 o 4, 10 a. • It• 5 • • 2 5 4 10 z 3 4 100 2 ' 3 4 1000 2 3

Body length (mm) elm o Fig. 16 % of pectoral fin length against body length.

VI) 50 40 50 ZO 10 0 43 1:t4 45 0.6 47 05 03 10 • I Le 1.3 L7 (nvt) mum m gr. 011m7c7.y î r4ill •± 1111/,'< (0.2mm .12),T04..,0'fte‹) OnM'nqii Figure 18 Distribution of egg diameter frequencies on total eggs (above 0.2mm.) included in 0.5gr. of a block of nearly • ripe ovary. -84- 126 A A. Specimen No. 1 ■ffl1.. • (Body length 86.2mm)

1111/111e/ B. Specimen No. 7 (Body length 138.7mm) %Pss-e

1111111/ ///,'1Zià C. Specimen No.17 (Body length 206.5mm) Me-4

D. Specimen No.18 D din (Body length 219mm) St «ems

E. Specimen No.23 1 rommimumpsuemei (Body length 302mm) ) ■ 4er: \tV•1 11%»

F. Specimen No.24 (Body length 404mm)

. ... . u . • 1 G. Specimen No.28 . • 1 • , (Body length 573 mm),

_t H. Adult. H (Body length 1350 mm)

Body length; ±7fiiiM11 1.) hypural bone 0);i:ee'CODP:ce * The distance from the posterior end of the upper jaw to the te inal 1 • )r)1 0 elle-. 47.j Meelt of the hypural bone. Fig. 17 MorphologiCal changés occurring through the growth of the swordfish. •

1

•

- 85 - a 1.5 1.0 • t • L• a te• Nov. 0.5 • •0 0

• • • • • • • Dec. • • of e.• • 0 ‘1_40..1 • 9 10 • • ••• • Jon. 14, •l ebtle t •e. V 1. -g. 0 à1 • 8. 05 • • • Feb. • 0 î 0 SO 90 100 110 120 lZJ 140 150 160 170 180 190 200 210 220 230 240

1.5 b oct.—san. • . • • 1.0 er 0 0 .51 .... • • • •• _ -. : • •,. •1 • • • 0 0 - SO 90 100 110 In 130 140 150 160 170 100 190 200 210 220 230 240 Length of body in cm. (Eye-caudal/0re) M. 1 9 :Itei;W•ifif,:1 1.!.) Y11?-1111-1:102ff; a. 140°,-450°E, 30'N * northward b. 160°D- 150°W, Hi:** ** same as above Figure 19 Length-ovary weight relation of swordfish from the North Pacific fishing grounds.

/2.0

110

100 ?".

00

8.0

Is II 4. 7.0

rela -4- 50

40 • #

30

zol • • • • • • • • 10 i e • à • : • • • • • • • 80 50 te1 110 rz0 130 10 r.-a toe no 100 153 2 0 2I0 ??■) ?so : 10 1e^.111, 1'el h t«. 11)c - Cr..n11.40 i1.1201.Z1 /11::kzi) Pacific Ocean southward • 30°N P.l1110).11;),:31ifi'e * * The North A nun- ** from 30°N. Figure 20 ** The Indian Ocean. Length-Ovary %veight relation of swordfish from spawning areas,

— 86 —

111 1Ji_111_154 IN 117_ 113.. . 111 114 1 • I .e re, • me 44 m.4 T• _el — r • '''''''''' ...._ _ I., ("i‘. Vo .:.:, ,'.in-i.ri.‘.- -'OZ..--Z.:rr. .l.1•:'.F'- ';—1' — 2").P..c---- re _ »

- . 0"o Ce 30-'0 44, Ls> „ ,

"0 0'

• no III In no 1 33 no I ) 113 IN II 130 I» I 63 3» 133 e2IN J Fig. 21 Areas of capture of swordéish with ripe and immature ovaries. guEonmi * 0 3Izg. pj,..1-.0g.lft0)e.11"Yiikïn. ** te--É i***— i1gç ****

The present fishing groungs. * * The locations where the swordfishes were captured; whose ovaries were heavier than 3 kg. *** The .Koman numbers denote the month of the capture. * * ** The line of the libtropical Convergence.

103 tel 110 130 1 0 tel sea tel 110 1 2 110 1 3. 10

40 I e I

so 30

10

o/ Z .p. --e c--- 10 07 eJ ..% , ° ° "1 0 e C '12 0° --',4

' '''4 eo. et' --''' ° • 10 A o

ci"-i ,1 -- 20 Is 130

31 la

IC . .0 di 12 $o .s ILO 110 113 130 I 3 — 110 us III 110 171 180

e-1/2211 e k 111 ?1; Fig. 22 Areas of capture of young swordfish. d /I ; . 194 8-49 lit_ir 4 )- LI 2 )- . 40 •

• el) 30 C* , 1949 ,-50 4 )- • C• 20 • 2 )-

10 C d 1950,-51 4 I- Jun jui (nano Feb Mar Apr —may 2 )-- 4S231'54 11 f4e.5)-Ai ( -e 0 At - 1951-- 5 2 18°,-,23° N, 1480,455°E.) 4 ; Figure 23 •• distribution by 2 r-. The body length a month of young swordfish found r--.1.- stomachs of tunas and spe- in the 1952-.53 arfishes in the Marcus Island re- 4 gion (18°23 ° N, 148°.,0135° E) 2 _ - • a . 1953-54 4 ...

0 20 40 60 20 100 120 110 160 180 n. 2 1_

Black marlin 1954-55 Soil fish 4 - Yellourlin _ Dolphin 1955-56 Striped marlin 4 White marli Short.rsed - O. Speolish .-.-----,---- 61 81 101 121 141 161 181 201 221 241 2G1 ( cm) Bigeye t t ti ill 65 85 105 125 145 165 185 205 225 245 265 Blue shark 24 I'1 fli e k-stf.r.■ II M251'41 :11Itili.-À;:f-i-sp:(01; (140°.-460°E) 0.1.11, ■ 81;3111f,Mill:effif 8 1,.1111a..)) e 4:111llitvi(1948,--, 1 956 -1r ) Figure 24 Figure 23 Number of specimens of young Body-length compositions of sTord- swordfish seen by predator, fish from the North Pacific fishing grounds (140 0.--460^E) for eight-year

period from 1948 - 1956. • - 88 -

243

Leo 113 Re .3. 110 -if

10 60 40 20

20 41 60 10 1C0 120 141 tie 110 20 no ito 161 110 30 2 3 4 567i0 Ii 29 41 53 Awe in (mt. it ale 11 • (age in month) er2711 e2611 leli.(t(1)•!%.,; ;-) z) er fella] (nkk) 4rinf 1;z: .1: Z, Fig. 27. Figure 26 Linear tendency I'lotting length at age N against • of growth both in the young and age for the length compnsit- adult (Log) ions of swordfish from the North • Pacific fishing grounds.

• no E 1.1 133 tO 120 e, 110 te 100 o eo 13 "0 Th 0 .0 ea 60

10 • 10 0 2 4 i 2 10 12 11 24 30 ss 42 41 age in month

ffi28I1 .til • t ;:) e • Figure 23 The growth curve of swordfish supposed -89- • ••■

• ,, 2

• • . 7 7 . • ' - „

[ , • • • ... • • . ... • •

•

Fltc 1. 1. I •I` 554ni * 2. 254J 84 111 1 m ) • ** 3. -Imiee.:.- e:J%,!z.n•ii0.1); 23) *,** 4. J Jj y owil (,)00:;:ej 1. (3m 10 •.? 9 vléM) * * * * Young swordfish(SDecimen No. 23. The total length 554 mm) ** Young swordfish(Specimen No. 25. The total length 841 mm) *** The shape of the fin rays at the posterior part of the dorsal fin (Specimen No. 23) **** The mature eggs of the swordfish (egg diameter-about 1.6 mm e • solution) fixed with 1070 formalin

- - 90 • mle Y * * et n e * - (Table 1. Data on the capture of the larval swordfish.)

a A** **** ****** ***** 1 e 4 )1 El * t1; Ir.: lee * ll PI * ia. '''' 4.- 1911. mm Lat. Long. _ 1949. 33' N 151°40' E Surface 1 23.5 V- 8 18° Plankton tow h m - 4' V-26 26°04'N 125°36' E « 15-40 27.6 2 11.0 et V-29 28°47'N 123°53'E 4, - 25.6 3 27.4 1950. 3fr - 3 25°47'N 124°09'E 4, 23.6 4 18.6 1951. ■111-19 2°51.5'N 150°23.5' E Dip net - 28.9 5 45.0 . Surface 45.5 1952. %In - 12 30°36'N 132°17'E Plankton tow 08-45 29.0 6 et et 30° 19'N 132°37' E Dip net 16-45 29.4 7 . 48.0 Surface • 30.0 1953, V- 4 19°26'N 122°41.5'E Plankton tow 09-22 28.3 8 /1 V-13 20°59'N 133°05'E e 12-00 9 2,4.0 et V-17 19°23'N 122°52'E e 00-03 28.8 10 38.0 • et V-20 19°20' N 122°53' E .9 10-50 29.0 11 21.0 et VI-12 13°00'N 165°02'E 4, 11-37 28.2 12 25.0 ee VI-16 1°59'N 165°01'E et 16-00 • 29.7 13 22.0 /1 VI-30 1°53' S 158°27' E e 16-00 28.9 14 23.0 eI NU- 1 1°57' S 157°04' E e 06-00 29.0 15 21.0 1954. VI-11 8°43' N 164°01' E Dip net 08-03 28.3 16, 48 34.0,...,39.8 e VI-20 12°42'N 161°2&'E e 08-00 27.8 19 73.0 1955. VI- 1 17°00' N 145°30' E 4, 12-00 27.9 20 80.0 • Surface - Ca. 14 1956. 11-16 8°12' N 99°28' E Plankton tow - 21 • 1957. X- 8 11°59.3' S 147°40' E e 09-15 25.3 22 8.2 1958. 11-22 2°07'N 137°03.2'E 4, 10-06 27.8 23 Ca. 4.4 e 4, /a, 4, 12-54 - 24 5.1

ed, .7 . ..? ,.. 14-31 - 25 6.4 et e 4, 4, 14-31 - 26 Ca. 4.5

Date. * * The areaçof the capture. *** The methods of the capture. **** Time. ***** The water temteratures. ***** Specimen No. ***** * * Total length.

• • - 91 - ell 2 Il 311 • 11,1IS 1 rj< (Table 2 Numbers of larval swordfiSh monthly occurm ce)

n mb •• 7 8 . 11 12 ei le 1 2 3 4 5 6 9 10 p.t, im ei. le G 1 4 1 2 _ d Mar iana iiij M 2 1 . .. Marshall iiii ed 5 1 1 Caroline iiij tad 4 Solomon iil.: e 1 nee Java itil f

a. The region. b. Month. c. The Black Current Region. d. region. e. The sea of. f. The Coast of Java in the indian Ocean.

e; 3 e • 17. Ell 0- e ik et! (Table 3 Distribution of swordfish larva according to the depth of towing.)

• - a e - a el b tie eC ifir Pe: Q 5ili 11:11S Isie.:Ik 411' A H Oi • e 0.-2.n 110.--, a *gee 20m110,-,50in 2°-07' N 1958. 11-22 0830.-J3934 137°-08' E 27.8 0 0 .0 e 1106,-4215 « 1 0 0 .4«.fz---.g-.4.4mm 1254.-4400 ..7. 1 0 0 ,.., 5.1 1431.-4528 • 4, 1 1 0 « 6.1,4.5 el 1. ehl. 10,20,nlip --tvii2i0Josiffeff.tel (n •

2. 40,-, 50m13.Ff - - /serlikl it/ (e:-.1, 14 Sm) eten!Sul;ti:fealtr-a:Z)0 1 a. Date. f. Remarks. b. Time. g. Total length. c. Latitude and Longitude. d. Water temperatures(surface). e. No. of the captures in terms of the depth of water. • h. Note 1. In the surface layer of 10 - 20 m, the same type of the round larval swordfish net (2.0'm in diameter of the mouth) was used. i. Note 2. In the water layer of 40 - 50 m, a beam type of the middle layer troll (5 m in the beam length) was used. The depth of water is measured by the depth meter for the surface pulling-net method. • - 92 -

• W., 4 if) s Ni (Table 4 Stomach contents of larval swoi'dfish.)

a U 1Ll C. d mm Lat. Long. 0 26 e7 4.5 2°-07'N 137°-03'. 2 E Copepoda rft G re: • 22 8.2 11-59.3S 147-40 .E Mysis type 0 carapace (0.52mm) ri ci 21 è:a 14 8-12 S 99-28 Phyllopoda 1. Amphipoda 1 11 21.0 19-20 N 122-53 tet. 15 21.0 1-57 S 157-01 ft.i.r.ttiOnti•. MOD et f* I g 14 23.0 1-53 S 158-27 t, h 8 30.0 19-56 N 122-41.5 (ffhi;fe) 16 34.0 8-43 N 164-01 j 6 45.5 30-36 N 132-17 Istiophoridae 5.5 mm. 7 48.0 30-19 N 132-37 Istiophoridae 6.5 mm, WU 2 k

a. Specimen No. the g. broken pieces of the larval b. Total length. swordfishes. The eye lense 1 piece. C. Locations of captures. h. None. d. Details. 1. The head part of the larval sword- e. 6 individuals of the debris fish.(The kind was not known.) (Copepoda). j • The broken piece of the larval f. Digested materials. swordfish. • k . The eye-balls,2.

•

- 93 -

115e)zi.› k (Table 5 Data on the young swordfish from the stomach contents of the tunas and relatives, and caught by longline.)

Spec", Locality ' BodY * Date Predator •• men l ength No. Lat. Long. . 1 86.2 , 54.\it-- 4 11°22'S 101°05'E 2 94.1 '49. V - 4 20°06'N 148°10 1 E Shortnosed spearfish(10.1kg. S) 3 98.1 '49. V- 9 19°09'N 151°59'E Yellowfin tuna(132.5cm. ?.) 4 113.0 - - - - 5 114.1 '52. \I- 3 6°30'N 139°34'E Black marlin (142cm. .?.) 6 117.0 '57. 1ff -15 15°45' S 102°52'E Dolphin 7 138.7 '49. V -12 18°35'N 151°38'E Sailfish 8 139.0 '51.Yll- 1 3°06'N 163°09'E Black marlin (153cm. '') 9 150.0 '55. I -22 22° 20' S 174°52'W _ 10 152.0 '55. 1 - 26 23°39'S 179°49'W Black marlin (242.8cm. •?.) 11 163.5 '49.V-12 18°35'N 151°31'E Black marlin (156cm. '') 12 173.1 '55. 1 - 3 24°49'S 176°45'W Yellowfin tuna (125cm. •?.) 13 175.2 '55. I -27 23°24'S 1790 59'W Black marlin (209.6cm• .?.) 14 193.3 '49.V 18°,....19°N 151°•-•452° E 15 200.0 e e e . 16 202.0 « e • er 17 206.5 '52.111-11 20°57'N 149°36'E Black marlin (159cm. '') 18 919.0 '57.11 Maldive Is. (Indian Ocean) 19 230.0 '55. I -24 23°31'S 179°53'E Striped marlin (188.4cm• ) 20 235.0 '55. I -26 23°39' S 179°47'W White marlin (271.9cm. e) 21 242.0 '55. I -15 23°35'S 174°33'W Str;ped marlin (217cm. ) 22 - 290.0 '55. 1 - 20 23°23'S 175°37'W Black marlin (224.9cm. •Y-) 23 302.0 '58. 1l1-22 4°20'N 167°57'E ere-._Velh>7)1-) -Ctuï ,t,...- c, ** 24 404.0 - - - by longline 25 415.0 - Indian Ocean by longline 26 447.0 '50.M- 3 1°21'N 157°48'E by longl;ne . . 27 481.0 '50.Y11-13 . 1°16'N 154°27'E by longline 28 573.0 1 51.M1-29 0°49'N 159°47'E by longline

*Body length It.±.Z.11M11 hypural bone 0)e-"CODeo.

* The body length is the distance from the posterior end of the upper jaw to the terminal part of the hypural bone. ** This was captured by hooking the ventral part.

• -94-

• M, 6 e '(1 949-1957) . (Table 6 Number of specimens taken through the spawning survey of swordfish 1949,-4957.)

Specimen p e ' of larvae No. of youngs No. of fish with ovariesri No. Year ,

1949 1 ( 5) 3 (34) . 54 ( 95) 1950 1 ( 37) 1 (275) 29 (654) • 4951 ( 30) 1 (179) 17 (420) 1952 ( 21) 2 (208) 93 (482) 1953 ( 17) 8 (166) 1 (528) 1954 1 ( 15) 2 ( 48) 1 (178) 1955 ( 7) 1 ( 80)., 54 (930) 1956 ( 21)- ( 60) 2 ( 91) 1957 2 (219) 1 (229)

* eaelz:195841k 4 McDifÉf.i.17)ittri ei-YilopMelVin 7cit-ia-teeee.c9nura. atter.n. Larva-net 0.5mank,n.0,5a rte,

* In addition to this table, another 4 larval swordfishes were captured in 1958. The parentheses of each.cblumn indicate the number of the swordfishes tested for maturity and ovary weight, the number of the larva-net pulling, and the number of stomachs tested respectively.

ki"YAlif.t.1.0)1.151111-011M. (I 949-1958) (Table 7 'Pile months when fish with ripe ovaries, larvae and young's of swordfish were taken, by longline, larva-netor dip-net and, from stomachs, respectivjiy. ,

Month 1 Area Jan.Ireb.Mar.Apr.ls,lay Jun. Jul. Aug.Sep.Oct.Nov.Dec.

North Pacific, Ripe ovary 1 , West of larva 0 0 1 0 6 0 0 2 0 0 0 0 140°E. Long. young 0 0 0 0 North l'acific, Ripe ovary 0 0 0 1 1 0 0 303,--45N. larva 0 0 O 0 1 1 0 0 0 0 Lat. young 0 1 0 0 13 45 73 0 0

North Pacific, Ripe ovary • 0 0 0 1 15°N,---•2'S. larva 0 5 1 1 0 0 4 0 Lat. young 1 10 23 11 1 1 11 0 Ripe ovary 0 1 0 0 1 . 0 0 South Pacific larva 0 0 1 0 0 • young 531 0 2 0 Ripe ovary 0 0 0 7 ' 0 Indian Ocean larya ' young , • • _ - 95 -

;"fr, 8 e: JJ ).(i0) 1.C} !MU: (Table 8 The body length distribution by moni.11 of young swordfish found in the stomachs of tunas and spearfishes in the western North • Pac•ific.) • Mundt ; Jan. Feb. Mar. Apr. May Jttn. Jul. Aug. Sep. Oct. Nov. Dec• Length 8— 9 1 2 10-11 12-13 2 1 14-15 2 2 1 16-17 2 ' • 18-19 1 3 2 1 20-21 1 1 1 1 22—.23 2 1 24-25 1 4 1 26-27 5 5 1 • 1 28-29 1 5 1 1 30-31 2 3 1 32-33 34-35 3 1 36-37 3 1 38-39 2 40-41 * er.ed-.111110.1ktM , e-eon-co

* The body length in this table denotes the distance from the posterior end of the eye to the base of the folk-fin of the caudal fin.

e; 9 I Yi ek)Ataelig'Zfillni1 (Table 9 The seasonal average of body length by reglon of young swordfish.) • • _ R.eg ion Marcus I. Region Caroline-Marshall. Is. Region (15`, Month ..,25'N) (0°,-.45°N) Jan. Feb. . 25.0 ( 1) Mar. Apr. • May 17.1 ( 8) Jun. 25.1 . (17) 17.0 (1) Jul. 30.1 '(19) 26.2 (9) • Aug. 21.7 (7) Sep. Oct. 27.1 (1) Nov. 30.0 (5) Dec.

trallOMICk *

* The parentheses show the number of the young swordfishes.

- 96 -

'VO .A Ft'1") J i e (m) aeljoei son • (Table 10 The body length correlation between black marlin, the predator and young swordfish, the prey.) Black inarlin(cm•) 121,-42.0 141 ,-,1C0 161-480 181,-,200 201 ,-,220 221 ,-,2-!0 Young swordfish(cm.5-'■ 8-9 1 10-11 12-13 14-15 • 1 1 16-17 2 18-19 • 3 2 1 • 20-21 3 1 1 22-23 1 1 1 24-25 2 2 1 2 26-27 2 3 1 1 28-29 2 2 30-31 1 3 1 32-33 1 34-35 3 1 1 36-37 1 1 • 38-39 2 •

- (Table 11 The modal progression on the length compositions of swordfish for the period of 1918 to 1956.)

ifft a b C d

19,18-'49 78 (cm) 123 148 1949-'50 73 148 1930- '51 128 148 1951-- '52 98 (138) 1952- "53 73, 1953- '54 128 1954-'55 7 1955-'56 73 103

• — 97 —

12P. a • (Table 12-a Stomach contents of young swordfish from the stomach contents of the tunas and relatives.)

x Specimen Body Stomach contents No. length nini 3 98.1 Empty 4 113.0 3 unidentified fishes, ca 25mm. 5 114.1 1 Echeneidae, 32 nun ; 1 fish vertebra. 7 138.7 1 fish vertebra ; part of crustacea. 8 139.0 1 fish vertebra ; 2 amphipoda. 10 152.0 Empty 11 163.5 1 upper jaw 'of . 12 173.1 1 Stromateina. 13 175.2 Nearly empty 14 193.3 1 Acinaceidae ; 1 Lepidotidae ; 1 unidentified fishes 15 200.0 2 fish vertebra. 16 202.0 1 Lepidotidae, 33min ; 1 fish vertebra ; 1 amphipoda. pair of octoptts 17 1 Lepidotidae, 35mtn ; 1 pair of squid jaw ; 1 206.5 jaw.

19 230.0 1 fish vertebra ; 1 squid. • 1 Balistidae, 30min ; 1 unidentified fishes ; 1 pair of squid 20 235.0 jaw (stomach contents of Balistclae?). 21 242.0 2 unidentified fishes. 280.0 Empty 22 290.0 Lepidotidae. 57min ; 1 Acinaceidae, ca. 110mm ; 3 Acinaceiciae ; 3 fishes vertebrae ; 1 pair of squid jaw ; • 1 pair of octoptts jztw. 151.6 5 pairs of squid jaw. 158.0 1 Echeneichte, 28min ; 1 Echeneidae. -171.0 1 unidentlfied fishes, 38min. 262.5 1 amphipoda (Macrura or Euphausiclae)

I2 h Ato.) I (Table 12-b Stomach contents of swordfish caught by the lengline.)

Specimen Body * Stomach contents length No. 23 min 302.0 1 unidentified fishes (Lepidotidae ?) 26 .447.0 3 Lepidotidae, 53,70,33mm ; 5 Lepidotidae ; 1 spuid mantle length C2mni ; 2 pairs of spuid jaw ; 4 fish vertebra ; 4 Cephalopocla. 27 481.0 part of Clololadis saira (bait) ; 2 Lepidotidae, 30, 45mm ; part of fish vertebra ; part of Acinaceiclae (only head) ; 7 squids, mantle length 20-40min ; 2 Amphipoda 15inni ; 1 shell fisht 425.0 1 unidentified fish. 1 Cololabis saira (bait) ; Alepisauridae jaw ? ; 483.0 1 Chiasmodont idae ; 1 uni denti fled fish. 1 Cdo/abis sai•a (bai t) ; 1 squid or ; 1 Lepidotidae. ; 435.0 1 Acinaceidae.

* Body hypural bone c0;l:. ■il'eCt/.).1 ,'::

* The body length in this table denotes the length from the posterior end of the upper jaw to the terminal point of the hypural bone. eu it I.f.t Appendix 1. Measurements in mm and counts.

Specimen No. 24 25 22 2 4 12 3 16 1 10 1-1-7--- 18 5 7 19 20 _Portion Total length 5.1 6.4 8.2 11.0 18.6 25.0 27.4 34.0 38.0 37.7 39. 8 45.0 48.0 73.0 80.0 Standard length 4.8 6.1 8.0 10.7 16.2 22.1 25.0 31.2 33.6 34.8 36.7 41.5 44.0 67.0 73.6 Body length 4.9 6.2 5.0 6.0 9.0 12.1 14.5 16.6 18.6 18.7 19.1 23.2 24.5 38.2 41.0 Snout length 0.5 1.3 2.3 3.6 6.t, 8. 6 10.2 13.0 13.7 14. 5 15.4 17.3 17.2 26.0 29.5 Upper jaw 1.0 2.0 3.2 4.4 7.6 9.8 11.6 15.0 15.6 16.6 17.5 19.5 19.7 29. 2 32.7 Lower jaw ' 1.1 2.1 3.0 3.8 6.0 8.6 9.5 11.7 12.4 12.5 13.7 15.5 23.6 26.0 Pectoral length 0.8 0.9 1.7 2.1 2.3 2.8 2.5 2.7 3.4 3.2 6.2 6.8 Orbit 0.6 0.8 0.9 1.1 1.2 1.5 1.5 1.7 1.8 1.8 1.8 2.0 2.1 3.5 EYe diameter 0.5 0.6 0.7 0.8 0.9 1.2 1.1 1.4 1.4 1.5 1.5 1.7 1.7 2.7 Head length 1.8 3.0 4.4 5.6 8.5 11.4 13.5 16.7 17.5 18.4 19.6 22.0 22.4 42.8 36.9 Dorsal rays (Number) 41 43 46 46 46 47 Anal rays (Number) 16 16 18 17 17 17 Pectoral (Number) 17. . 18

Standard length The distance from snout to posterior end of urostyle. Body length The distance from posterior edge of upper jaw to end cf urostyle.

• • •

- -

1-17:

f./.1 e e Appendix 2. Measurements in mm and counts.

Specimen Na. I 2 3 4 5 6 7 . 8 9 10 11 12 I 13 14 15 16 17 18 19 L 5 21 22 23 24 5 5

' Total length 160.0! 162.1 2o7..j 2o5 • a. 204.0 240.01 249.3 • 269 273.0 • 3L1. 355 359 45 424.0 52 551 EV MI 972 158 EY t -for:: length 101.4 • 139. 131.3i 157.61 ... ' • 721 • • 2.10 • 223 245 268 295 55 54.0 377 322 459 468 .55 542 51 Standard length 141. 157.F 184. 181.0 184.5! 5111 222.4 • Z33 240.0 • 305.1 314 3,7 58.0 478. 477 722 731 51 1052 Body ler,th • 115,. 91.1 98.1 113,0 114.1 117.0 15.7 139.0 • 150 152.1 1C3.5 173.1 175.2 193.3 • 200 • 202 203.5 .219 Z70 235,0 212.0 254 52 gr,: 415 447 4e. 1 E.„73 5, Sot lern.th 52... 57.f 65.6 64.5 C3. 7.1.• 74.6 • 78 78.0 • 101 • 105 98 .122. 111.0 172 152.2 5.3 5.3.' 57 .7; 442 Dia of m tit • 9 ' C. 4.8 5.3 76 6.31 7.0 7.6 ', 11.6 12.6 16.4 14.' 21.5 22.1 21.5. 5., z,.... , . pos,,bital 7.7 11.4 11.0 10.5 11.4 • 14 15.8 • 15 • 23 • • 22 22 27.3 26.6i 25 4fJ.4 70.4 77 ;..a. 84.9 14 Interorhital 5. • 5. 7.4 5.9 7.6 7.6 7.8 • 13 15.0 • 15 16.0 14.5 23. , 21.4 .5 5.4 42.'1 48.9 C5 Bead length CG. 57 84.0 82.3 80.8 96.4 • 102.6 • 137 • 138 1 130.3 151.0 25. 207.5 '374 276 416 .575 Length o: U. j •w £9.0 53. 73. 69.8 70.0 84.1 82.0 88.3 88.r • 124 117.51 110.6 139 128.3 193 176 223 319 252 494 Length of L. jaw (2)z)38.. 50 49. 50.3 49.6 51. 5G.2 • 72 58.4 76.5 83.3 • 87.5 77.4 78.0 88 90.3 82.4 89.5 1153 107.4 133 129.3, 141 147.1 ?.. 0.01 u.j.10 lot A. 45.4 57. 59.4 61.0 55. 73.• 75.3 • 82 78.0 98.7 92. • 101 101. 100.7 111.3 112.2 118 1z3.2 131 158. 172 279 221 '253.5, 341 3 Pectoral length 1.9. 17. 2.1.• 22.9 21. 29. 5 30,, 31.1 • 3848. 60.0 44.5 49.7 61 C.4 173.5 61.5 80. 1 5.3 119.r 134.2(1...) /X 143...,' 100.1 , leight 1st do3na/ (5th) 8.4 1j. 12.4 18. 12.7 18.5 19.2 19. • 29.6 33.4 23.5, 29.0 43 46.7 40 (Gth), 37.3 e.-4. ,. c9.3 1/5.1 117.3 1'5.11 /40.4,1 175 4, (11th) • 11.0 10. 14.4 (r.g)16.5 18.1 19.2 19. - 20.0 28.5 17.51 28.0 38.* 34.0 35-51 35.5 37.13 42.2 39.j 41.' 5.1 17.Ld 78.n ,, (middle) 20. 24.0 18. 24. 33.4 43.7 ( 3)21.0 41.0 51. 43.5 45.,1 I 47.3 C.11 . 57.1 63.r 54.1 47.4 75.03 22 ierght of anal . 8 • 11. 8.5 12.3 13.0 15.2 15.3 18.1 15.5 18. 21.4 • 20 28. 3 18 5.6 34. 32.1 29.c 34.r. 4351 65.1 C,.1:y..,.5 79. 95 '..ength of U. caudal IG. 1S. 24.5 21.4 27.8 35.2 37.8 11.3 36 44.4 50.0 5.1C 38.6 48.0 61.6 68.3 55.0 • 64 93. 91.2 124.4 121.2 212.4 body ueight 1.5 2. 5.5 8 11.5 13.' 15 17.5 17 18.3 912 're.,,I,I.:, 111/.! 19:0 's: dorsal finraY 50 159 43 42 ' 44 47 45 44(7) 4 } 48 /47 145 147 14G 147 114 4 43 1 47 'I 45 ,3 1 ,,, 42 44 43 'ad dorsal finray 3 3 J I I4 4 4 3 3 ,,nal floraY 17 3 (;. 15 118 18 18 17 1 1 18 118 116 1 17 118 118 117 1G 19 1 17 14 14 1 51 , 14 11 14 14 15 12 2'od anal finraY 3 3 4 4 4 3 3 4 I. ,, e3tor:..1 finraY 7 17 . 18 16 18 17 18 17 17 18 16 17 19 17 17 17 18 18 17 18 19 19

Stnndard ength The distance from snout to posterior end of hypural bone 1.1ye- font len :tla bit dirtance froin the poste, ior Body length The distance from posterior edge of upper jaw to end of hYPural bon. . , mart,in of e orbit the conter my n of the tail • rartcrior edge of upper jaw to 1st tine!. • - 100 -

Appendix $. Y oung swordfish from the stomach contents. Size 'C'G).!::;;,"... a * Total length : * Swordfish from Predator stomach contents Date Remarks Locatay B.L 1 Species (cm) Sex No. Size (cm) 1949 (17) Shortnosed 1 May 4 20017.'N 14810 1 1: spearfish (2.7) 15 Dolphin 121 8 3 13.13,10 /1 9 19'0'7 15159'7 Yellowfin tuna 133 1 15 Blat.•1: marlin 164 ô 2 V.L 15 /1 10 18'2C.' // 151'10' // Striped tnarlin 152 9 1 30 /1 11 1818' Y 15 1 . 1)'"/ Black marlin 162 8 1 /1 12 18j3'', 151 . 3e// 156 1 21 Sailfish 180 9 1 20 /• 15 1838 , 7 1.11 2i1'7 192 9 2 June 22 22'56'7 1S 52'7 158 9 1 27 // 23 22'53'7 1 9'.7 Illack marlin 202 9 1 V.L 11 .7 25 22 . 16'7 152 31' /1 196 2 26 152•19'e/ 156 1 26 271 22S'.7 11 142 8 1 23 161 8 1 28 153 1 32 167 8 1 187 9 1 25 • Dolphin 113 9 5 27 27,18.5 /1 28 2:? . 511'« 152:12' Black marlin 174 1 21 163 8 2 160 8 1 20 155 ô 1 144 8 1 162 8 1 31 11 153 1 /1 29 22'15'', 152 . 40'7 164 8 2 20 • :111,22 49'7 152'40'7 // 175 4 July 1 22 •7' ,7 152 . 51'/, 179 1 24 165 2 12 Sailfish 149 8 4 30,30,30 1/2 21'56'N 152 •06'E Black marlin 161 8 1 17 158 8 1 151 8 2 25,22 173 8 1 27* 1950 Feb. 17 151'15'« Striped marlin 117 6 1 25 PoY 15212'7 Black marlin 171 6 1 30* Lower Yellowfin tuna 98 6 1 jaw only Black marlin 154 6 1 58* e 11 1 . 14' ,/ I53( ee 11Itite marlin 134 6 1 33 V.L Ca..- .1 13 116'7 153 . 27' 'i Black marlin 160 6 2 178 6 1 34.7 • 14 1 '31 1 r." 15109'7 169 6 1 /1 15 2 . H' 15-1 '11' 151 6 4 • IC 257' 151'08'7 2261 ?. 1 35* . 1631 22; 1 V.1. 26 • 17 $ '33' 15500'7 189 6 1 27 16F. 1 31.5 201 ? 1 Jaw only .7 21 552' // 1.1300'7 151 1 V.I. Ca. 20 _ ..■•■ eYe hall a. :Ole size is the length from the posterior end of the to the tip of the folk-fin. a Japanese unit of weight(1 kan is 8.28 pounds). b. Kan-- of the folk- ** The length from the tip of the lower jaw to the ' edge fin.

- 101 - • Sworct t j sh f rom Predator stomach C()fltimlt .s. Date Loca ty Remarks 11.1. c „,I No. E..ize (cm) Species (cm) "T.7 - 52'N 148000'E Black marlin 171 1 67.* July 21 50 1 Vertebra e 22 637' 14V42' 'i 137 S ii 23 7°50 ' 1.l7°25' 'i /1 156 3 Vertebra /1 165 3 41

.^ 159 3 1 V.L 25 Aug. 7 1°10.5' /./ 150°14' /1 154 3 Ca. 9.5 Snout /1 // 14 4°19'e 161 033.3' 161 3 ; only • 23 70 55' 162'33' /1 198 3 Ca. 18.5 e 25 8041' 161°25' 1621 8 Ca. 16

1951 Uppe r 1 June 30 2°45r// 162°44' e Black marlin 111 jaw only July 1 3005' 4/ 163009' /1 153 2 14.5. Ca. 14.5 4/ 165 3 35 e 3° 42' 163007' 167 3 1 Jttly 10 4'23' 165° 25' • 21 5°49'' 16S004' 'i 168 o 1 Ca. 13 Upper Aug. 3 5O35Fì, 17234'e 168 jaw Only 1 • 4 6°05' 173°08' /1 172 Ca.. 9.5 e 6 8°32' e 171 028' e 173 o 2 Jaw only 167 o 1 Ca. 35 6°17'e 169°40' /1 171 o Ca. 32 /19 1 // 15 5°43.5''i 173°45' 206 V.L 42 144 3 30 ./ 174°22'e 1/ 180 3 1 V crie bra /1 16 5°33'./ 1 Sept. 5 3°08' ,/ 160 009.7' /1 167 3 1952 1 • May 29 6°24' e 154° 15' Black marlin 104 (107gr) June 2 13°55' 151'15' 184 9 (1gr) 151. 8 5 (1)g r ) 158 o 2 (20g r) 1/ 3 14°54' 150°55'e 1 1/ 3 6°30' 139°34'e .,/ 142 (5gr) e 5 17°19' 153°14' Sailfish 138 3 (7g r) ',S 19°31' 151°08' gey e tuna 137 ( 10g r) e 9 19'54' 4/ 119'3S' Black marlin 182 8 Ca. 27 4/ 159 o ▪ 11 20°57' e 11936' (Cgr) 11 159 3 (5gr) 170 (70gr) 159 o • (46gr) Sail 'fish 157 o (7gr) e 12 21°48' 1d3°38' 'i // 150 o (10g r) Snout Si. // 13 22°28' 147°08' 4, 41 156 Vertebra Black marlin 164 (3g r) on ly 156 2 (38gr) /1 156 8 (12gr) 1/ 160 o (8g r) 41 161 1 e 14 22°54' 146°18' e /1 192 (30g r) 15.1 (5g•) hl 153 3 (20gr) July 2 24°04' e 150°23' 4, 152 ( 20g r) Yellowfin tuna 116 9 1 38*(t:Ggr) /14 21°44' 4/ 150'12' Ill at: k marlin 151 2 (25g r) . /1 156 8 1 (4g r) 3 Total we- 119 O 30,38*, 22, ight 60gr 41 169 o 3 (45g r) Snout 1/ 171 Vert e bra only • - 102 -

, 1 Sv )rd f i sh from - -- — * * — — — ------— I-- 1 reclator II toinaell contents• .. _.....--- Date Li , cality Remarks ' I'LL, Isey . No. Size (cm) Specie:x ((I;) ...... _... ...... . ...... July 4 21 4;'N 1:••• 1:1ad.'• riarlin V:: '• -1 2i(25gr) 4 Il l'..1:, i 1 9:. * e n • eI. 2•)* If W. 3 1 /1 1,7...', .. i e 5 21 .- 23'e 1Z'; 17'e e 1:4: 3 1 27*(2Igr) /1 14:-. .3 • 2.1* e 7 IS• 17' e 151 - IS' e /1 17" 5 2 27*,4:%* /1 16!) .3 2 • 0*,30* « 1u 'Lill l'e 148 - 55' « 1., 166 ô 1 25* /1 16 10 OS' e 158 -'43' e /1 161 3 1 20 Shorst rez e 23 1800' ,/ 15352''/ st'rl 148 ô 1 V.L 20 ish Snout Black marlin 201 1 only /1 146 6 1 // e 24 •18°00''i 15322'', /1 141 ô 1 V.L 30 • e 176 ô 1 30* . /1 180 ô 1 33* 172 8 I 27 162 ô I V.L 20 Total we Albacore 101 î 3 394. ,354 ,32e ight 150gr •/./ 25 17'54'e 153°22'e i Black marlin 159, 3 1 Jaw only e • 168 ô 1 e 1716 1 Albacore 101 q 2 V.I. 20 e 23 1906'N • 15416'E Black marlin 219 ?. (57gr) /1 154 ô (45gr) 161 13 3 32» 178'.73. 1 20* Snout 149 .6 1 only 159 8 1 27 . Snout e 27 1837'', 154'07 e e 152 ô 1 only ..,/ 163 Ô 1 il // 155 ô 1 e 174 Ô 1 • Sailfish 184 ? /1 29 2224''i 15255'« Black marlin . 165 `V 1 40*(350gr) e 160 V 1 V.I. 15 « 31 24 034' « 15219'« e 155 8 I (5gr) , e 161 8 1 27» OC t. 30 3'56'', 175'22' « /1 162 8 1 27.5 Nov. 1 2- 03'e 173'•16'e 166 8 1 • 23 /1 8 2'27'S ]7(322'', e 158 8 1 V.I., 16 185 8 1 23.5. 159 V 1 // 9 nil'« 17624' /1 164 8 1 11 13 207' 17631' 216 î I 32 1636 1 e 14 205''' 176'33'e // 180 8 1 28.5 e - 162 8 1 38.5* Snout e 15 2'll'e 17615'// YellowfYellowf in tuna 129 1 only 1953 Mar. 14 2916'N 15352'e Blue shark 172 . 8 1 1954 • ..lunc 19 15'09.5'e 16314.5'e Black marlin 166 8 1 17 — 1 03 —

Swordfish trout - Predator stoniach contents Remarks Date Locality ILl. Species (cm)._Sex No. Size (cm)

1953 Jan. 14 23°32.2'S 174°37'W Stripe,d marlin 2W 8 1 28 White marlin 174 3 1 31.5 Sailfish 187 9 6 21.5,30,17.5.17.5 17.5,17.5 e 15 2335.1' 17e33' Black marlin 277 . 1 Ca. 70* 2 7 Jaw only 2 9 White marlin 163 p 2 28*, 38* • 16 23'26'e 175°15'e Striped marlin 2i:13 8 1' 32* 193 8 1 Yellowfin tuna 12.i. 8 2 9,23 • 23° 17.8'e 175°13'e Striped marlin 201 3 • 1 28.5 White marlin 236 3 1 39* ii 23124'01.5'« 179°21.5'« Striped marlin 2ns y Sailfish 151 9 1 36* ei 24 2331' 179° 53'1?, Black marlin 155 8 1 36* Striped marlin 202 3 1 30 • 23 23°28'e 179'41'« Black marlin 166 a 1 47* • 26 23°38.7'e 179 °47'W 201 8 1 24.5 Striped marlin 193 8 I Vertebra 201 8 2 • 27123°23.7'e 179 °59.5' ,/ Black marlin 184 3 2 28k' ,19.1 216 q Yellowfin tuna 129 y. I Vertebra 159 3 I 17** White marlin 185 3 1 Jztw only • 28 23°33.5'e 179°16' 1 Striped marlin 193 9 1 Il 225 3 3 e 29 23° 11'e 179°34'« 218 Jaw onlY Black marlin 170 3 1 227 9 2 221 9- 1 35.5 /1 30' 22'46.8'« 179°09'e 213 9 '1 Jaw only Feb. 2 18°58.4'e 176°26.5'e 186 3 1 1956 Nov. 23 16° 10'S 146'22.8'E White marlin . 217 8 1 43* • 27 19'41.3'e 15231'e Sailfish 201 3 1 1958

Aug."•-• 25°,--■27° • I Sept. 153°.--,155° « 2 Aug. 21 5°21'N 70°00 1 e Nov. 10 2003515 52 u3' Yellowfin. tuna 1556 1 15 e 23 21°04' 52'31' 158 3 1 19 ii 27 20051'« 520 16'e Black marlin 202 9 I Ca. 30 Dec. 9 20040 1 « 49058 ,/ 177 3 I 18

V.I, . Vertebral length