Synopsis of Biological Data on Frigate Mackerel Auxis Thazard (Lacépède

Species Synopsis No, 8 FAO Fisheries Biology Synopsis No, 51 FIb/S51 (Distribution restricted) SAST - Tuna

SYNOPSIS OF BIOLOGICAL DATA ON FRIGATE MACKEREL Auxis thazard (Lacépde) 1802 (PACIFIC OCEAN)

Exposé synoptique sur la biologie de ltauxide Auxis thazard (Lacépde) 1802 (Océan Pacifique)

Sinopsis sobre la biología de la melva Auxis thazard (Lacépde 1802 (Océano Pacifico)

Prepared by RICHARD N. UCHIDA U. S, Bureau of Commercial Fisheries Biological Laboratory Honolulu, Hawaii

FISHERIES DIVISION, BIOLOGY BRANCH FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 1963 2'41 FIb/'SSl Frigate ckerel 1:1 iIDENTITY variable vascular system, and only in minor details of that system, cannot exist in an equal 1. 1 Taxonomy status with the other four orders of the Teleostomi ami should, therefore, be thrown 1. 1. 1 Definition (After Schultz, 1960) out. Another argument against the use of Phylum Chordata Kishinouyes classification wasgiven by Subphylum Craniata Hildebrand (1946). He stated that difficult Superclass Gnathostomata dissections are involved In followi ngiKisbinOUY&B Class Osteichthys classification, and some of the characters are Subclass Teleostomi scarcely usable except by an' expert. Superorder Teleosteica Order Percomorphida Wade (1951) pointed out that Herre (1953) Suborder Scombrina and Jordan (1923) placed the so-called Family Scombridae scombroid fishes in two families, the Scorn- Genus Auxis Cuvier and Valenciennes bridae and Thunnidae. Berg (1947) in his 1831 classification created an additional family, Species Auxis thazard (Lacpède) 1802 which he called Cybiidae. Fraser-Brunner The establishment of the genus Auxis under (1950), on the other hand, rejected any diviSion "Les Scombres" first appeared in Cuvier's of the family Scombridae, saying that atterppts Règne Animal in 1829. Kishinouye (1915) hailed tosubdividethe fanily on the basis of lesser this work and stated that this marked a great characters have "resulted in arrangements, advance in taxonomy. However, from the time which are artificial and have left the classifica- of Cuvier's work to the present, the genus Auxis tion in an uneasy shifting state." has had several reclassifications. Even the species included under this genus have been Thus, the placement of the genus Auxie confused, with the result that to4ay several depends on the taxonomic authority one wishes names exist for the two or three (?) types of to accept. 'Auxis in the Pacific. 1.1.2 Description In classifying the genus Auxis, Kishinouye (1915) first included it in the family Thunnidae. - Genus Auxis Cuvier and Valenciennes However, in a later work (1917a), he created a 1831 new order of the Teleostomi and called it ìecostei. He placed the families Scombridae "Body oblong, plump,my naked posterior- 'and Cybiidae in the order Teleostei and the ly, anteriorly covered with small scales, those families Thunuidae a Catsuwonidae under his of the pectoral region enlarged, forming a new order Plecostel. H placed the'genue. corse1e; snout very short, conical, scarcely Thunnue under Thv,ndae and the genera compressed;mouth rather small, the jaws Kate uwonus. Euthynnue, and Auxis under the equal; teeth very small, mostly in a single family Katsuwonidne(Kishiaouye. 1 923).,The series, on the jaws only; tail very slender, order Plecoetci was establishedsolely onthe depressed, with a rather large keel on each basis. of a partial variation in the vascular side; fjrt dorsal short, separated from the system. The primary characteristic of the new second by a. considerable interspace; second order was then the presence of well-developed dorsal and anal small, each with 7 or 8 finlets; subcutaneous bloodvecelcand the secondary pectorals and ventrale small; no air bladder; characteristic was the development of dark rèd branchiostegals 7; pyloric coeca dendritical; lateral tissue in relation to the eubcutaneoto gill raks, very long and slender, numerous; blood vessels. Another difference pointed out vertebrae 39 in number, peculiarly modified, was the difference in the kidneys. and the vascu- essentially as in 9da." (Jordan and lar systems within the kidneys. Evermana, l805)

Tkahashi (1924) refuted Kishinouye's belief About the genus Auxis,Kishinouye (1915) in the need to create a new order and presented wrote that this group is more degeaera.e than his argumsnt. In brìef he stated that the new Euthynnus, and accordingly differs widely frOm order Plecostei which io established solely on the other chunnids. The haemal spines of the the basis of a paria1 variation in the highly thoracic vertebrae do not form a haen-ìal arch, 2Lf2 1:2 FIb/S51 Frigate Mackerel the first vertebra is not fused to the cranium, the body. The outline trails posteriorly, and the first and second dorsals are not con- toward the origin of the second dorsal fin. tinuous. There is no air b1ader.It is a small From the anterior end of the dorsal wedge, tlié fish about one foot long, with a short snout and dorsal profile of the middle extension of the coloration roughly the same as that of E.yaito. corselet trails posteriorly and ventrally toward However, there are no spots below the pectoral the lateral line and meets its complement which fin. begins near the angle of the opercie and rises obliquely toward the lateral line.The lower - Auxis thazard (Lacpde) 1802 wedge begins near the angle of the opercle and trails ventrally toward the tip of the ventral The following description of A. thazard is fins.Variations in the length of the corselet quoted from Matsumoto (1960:174) who examined occur only in the middle branch which roughly five specimens of this species: follows the lateral line; hence the term corse1et as used in this paper shall refer to this middle "Dorsal XI, 10-12, 8.Anal 13, 7.Gill extension." rakers 9-10+1+28-31= 39-42.Total length 272- 283 mm. On external coloration of the live specimen, Serventy (1941) stated that A. thazard resem- "Body robust, more or less compressed bles E. alletteratus, commonly called mackerel laterally. Snout short, pointed.Mouth moder- tuna, in having a wavy mackerel-like pattern on ate; gape to well past anterior edge of pupil. the back.This pattern is, however, somewhat Each jaw with single row of small, weak teeth. Indistinct in A. thazard and instead of being on Palatines and v'óìer toothless. Dorsal fins a dark green background, the markings are laid well separated. Dorsal interspace less than on a lead -colored one.After death, the fish half the distance between the origins of the presents a shiny, lead-like appearance, which first and second dorsal. somewhat resembles the lead-pencil shading on note paper and to which the name "leadenall" is "Vertebrae 20+19= 39, including urostyle. due. First haernal.arch on 8th vertebra; first closed haen-ial arch and first haemal spine on 21st The color of a specimen preserved in alco- vertebra. Haemal canal borne away from body hol was noted to be blackish-blue above, lighter of vertebra by pedicles. below, and becoming silvery on the belly.The color of the fins was the same as the adjacent "Body naked, except for corselet of scales. body color (Jordan and Evermann, 1905). Corselet along lateral line extends posteriorly to about two thirds the distance from the origin 1.2 Nomenclature of first dorsal to the origin of second dorsal. Lateral line only one or two scale-rows wide 1.2.1 Valid scientific name beneath second dorsal origin.Lateral line ma or less undulating, without any pronounced arch, - Auxis thazard (Lacpde) 1802 "Body markings about 16 dark, oblique bars There is much confusion at 'present among running posterodorsally and overlying bluish taxonomists and hence in the literature as to background above lateral line. Bars variable the number of valid species of this genus. in numbernd often broken into spots. Dark Evidently, there are some who believe that continuous band over top of head and along there is only one single world-wide species and dorsal margin of body.The band more or less this is A. thazard. There are others who just uniform in width to above tip of pectorals as firmly believe that one or more additional whence it narrows posteriorly to base of second species are to be found. dorsal finlet.Body below lateral line silvery white and free of markings or spots." 1.2.2 Synonyms (Fig 1.) In the Pacific Ocean, the scientific names Matsumoto (1959) descihesthe corselet which are ascribed to A. thazard or some of as "a plaque of scales on the anterior part of the other closely related species are given the body in tìfrm of three wedges, whose below (De Beaufort and Chapman, 1951; Rosa, àpices point posteriorly.The dorsal wedge 1950). begins near the tip of the pectoral fin, halfway between the ],ateiai line and the dorsal edge of 243 FIb/S51 Frigate Mackerel 1:3 Scomber thazard Lacpde, 1802 collection of six specimens from Woods Hole, AuxiB taso Cuvier and Valenciennes, Mass., Hawaii, and Java agrees in gillraker 1831 count of the lower gill arch with Auxis thazard Auxis thyrmoides Bleeker, 1855 as named here. The specimen used by Walford Auxis roch ei GUnther, 1860; Steindachner, (1937) to illustrate Auxis thazard is clearly 1868; Mellis, 1875; Jordan identifiable as A. apeinosorna with its long and Gilbert, 1882; Goode, posterior extension of the corselet along the 1880; Steindachner and lateral line.It is not known whether the east- Doderlein, 1885; ern Pacific forms are identical with the species Kitahara, 1897; Hoek, occurring in Philippine waters, and a careful 1914; 8orja, 1920; Travis, study of a considerable number of collections 1925; JenkIns, 1925; will be necessary before this can be Jordan, Evermann, and ascertained." Clark, 1930; Irvine, 1947 Auxis hira Kisl2inouye, 1915; Jordan Kishinouye (1915) stated that there are two and Hubbs, 1925; species in Japanese waters which are distin- Soldatov and Lindberg, guished by differences in the number of scales 1930 on the lateral line and in the breadth of the body. Auxis maru Kishinouye, 1915; Soldatov In the species he consequently named A. lira, and Lindberg, 1930 le noted that posterior to the end of the corse- Auxi st apei nosoma Bleeker, 1854; Verhand, let there are only one or two rows of scales 1846; Ginther, 1860; above and below the lateral line, while in the Wade, 1949 species he name dA. maru the median portion of the corselet becomes very narrow and ends In a paper presented for discussion at the posteripr to the anal fin. He further stated Pacific Tuna Biology Conference in }ono1ulu, that A. maru is probably the same species as Hawaii, in August 1961, Roedel and FItch A. thazard of the South Seas, however, it is reported on the taxonomy and nomenclature not known whether thazard corresponds to A. of the Pacific tunas.It would be appropriate lira or to A. maru. He conci uded that at this time to quote vhat these authors had to Bleekerts A. tapeinosoma may also be this say about the genus Auxis. They stated (p. 12), species, but the figure and description of this "We mention these fishes only because they fit species were very rough and unclear. This in the group as we have defined it. For sorne compeUec. Kishirnpuye to give these fishes the years we have been orking on genus Aqxis as new specific names of hira and maru. an off-time avocation. Any comment, other than to mention that this genus is as muddled A partial description of the external as any we have discussed, would be premature." features of -A, hia A. maru is given. Some of the works of other investigators Auzi lira Kl ouye are summarized here to illustrate the present confused state of the genus Auxia. "D. 10-11, 12,8. A. 13, 7.Gill rakers 9+30. An account from the work by Wade (1949:230) on the Philippine frigate mackerels states, "A "Body more or less compressed, its height survey of the available literature shows that is nearly equal to the length of the head. Mid- possibly two seemingly similar species occur dle limb of the corselet ends a little behind the in the eastern Pacific area. Comparison of pectoral, and one;or two rows of minute scales two descriptions of specimens of this genus are found on either side of the interal line." (Meek and Hildebrand 1923; and Fowler 1938) (Kishinouye, 1923' reveals that the authors were describing two entirely different species. Fowler's descrip-. Auxis maru Kishinouye tion based on two specimens from the Galapagos Islands off the west coast of South America "D. 9-.10, 11-12, 8.A. 13, 7.Gill rakers agrees with Auzis tapeinosoma as defined here, 10+36 having the elongate posterior prolongation of the corselet along the lateral line and the "Body fusiform, nearly rounded in cross- increased gill-raker count.The description section, and its height is snaUer than the by Meek and Hildebrand based upon a composite length of the head. The middle limb of the

24L 1:4 FIb/S51 Frigate Mackerel corselet is prolonged backward nearly the entire only one scale-row wide and extends posteriorly length of the lateral line." (Kishinouye, 1923) only to about midway between the origins of the first and second dorsal fins.In the second In a discussion of A. hira and A. maru of form of Awds, the corselet tapers gradually Kishinouye, Wade (1949) pointed out that the and extends to andin many instances goes be- description of the larger of the two Japanese yond the base of the second dorsal finlet. On species, A. lira, agrees quite well with the de- Auxis specimens 195 mm to ¿00 mm in total scription of the Philippine A. .tiiazard, whilethe length, the corselet is 9 to 18 scale rows wide description of the second, smaller species, A. just below the origin of the second dorsal fin. maru, seems identical with the species provisionally called A. tapeinosoma by Dr. Herre, Further research by Matsuxnoto showed formerly ichthyologist of the Philippine Fishery that the nomenclature of the long-.corseletted Program. On this basis, Wade provisionally form is quite confused. He stated (1959) placed A. hiram synonymy with A. thazard, "For many years, the name tapeinosozna and A. maru in synonymy with A. tapeinosoma. Bleeker was ascribed to such specimens taken in the Philippine waters. After studying Fraser-Brunner (1950), on the other hand, Bleeker's (1854) description of taeinos orna, believes that A. lira is a synonym for A. the author has come to the conclusion that this tapeinosoma. He states, "Specimens from is not the long -corseletted form. Bleeker Celebes, Amboina, and Japan have a slightly describes tapeinosorna as having a corselet longer postorbital part of the head; they repre- which 'ends slightly posterior to the pectoral sent a local subspecies (tapeinosoma, of which fins.' Most of the other characters he men- A. lira is a synonym).I can find no difference tions agree more closely with specimens of between specimens from the Atlantic or thazard than they do with specimens of the Melbourne, Australia, representing the typical Philippine long-corseletted form. Furthermore, subspecies, which also reaches Japan (A. rnaru = through correspondence with John E. Fitch, A. thazard)."Thus, Fraser.-Brunner indicates California Department of Fish and Game, who that he is in agreement with Kishinouye's state- examined the type specimen of tapeinosoma, ment that A. maru is probably the same species the author learned that Bleeker's fish is defi- as A. thazard. nitely the short -cors eletted form. Bleeker' s (1855) description of a specimen from Ternate, The FAO Yearbook of Fishery Statistics East Indies, which he named A. thynnoides, (1959) lists A. thazard = A. hira and A. seems to be the 1òngcorseletted form. He tapeinosoma = A. maru. describethis fish as having a corselet which "ends far behind the pectoral fin. " In 1951, Mead injected some doubt as to whether A. tapeinosoma was really the long- In 1960 Matsunioto wrote "It is corseletted form of Auxis. In a footnote, he apparent from the original description and stated, "Wade's descriptionf Auxis from Fitch's information that thynnoides is the tapeinosoma agrees with that of Bleeker (1854). earliest available name for the western Pacific However, the pattern and extent of the corselet long-corseletted species." Thus in his works scales in Bleeker's figure (1854, pl. 7) of A. published in 1959 and 1960, Matsurnoto called tapeinosoma agrees more closely with Wade's his long-corseletted form A. thynnoides figure of A. thazard." Bleeker, stating that the long-corseletted tapeinosoma of Wade (1949) and of Herre and Matsumoto (1959), in the course of his work Herald (1951) appears to be a misnomer.' on identification of tuna and tuna-like larvae, Matsuxrioto, therefore, is in agreement with also became involved in the identificationof the the 'statement made by Mead (1951). adult forms of Auxis.In his Daná Report No. 50, he pointed out that there is general accept- A. thynnoides Bleeker, shown in Fig. 2, artce that two forms of Auxis exist and these is described by Matsumoto (1960) wh9 can be separated frorn each other mainly by a based his description on 20 specimens de- difference in the corselet development. posited at the Bureau of Commercial Fisheries Biological Laboratory, Honolulu, Hawaii. Matsurnoto stated that A. thazard is characterized by a short corselet which tapers "Dorsal X - XI, 10-11, 8, Anal 12-13, 7. very abruptly at a point just past the tip of the Gill rakers 10-11+1+32-36= 43-48.Total length pectoral fin. From this point, the corselet is 262 mm - 290 mm.

2L5 F1b1S51 Frigate Mackerel 1:5

Fig.iAuxis thazard (Lacpède) (from Matsumoto,1960)

Fig. ¿Auxis thynnoides Bleeker (from Matsumoto, 1960)

26 1:6 FIb/S51 Frigate Mackerel Body robust, fusiform, almost cylindrical below.The list was abstracted from the in cross section.Snout short, pointed. MOuth compilation of scientific and common names moderate; gape to slightly past anterior margin applied to tunas, mackerels, and spearfishes of pupil.Each jaw with single row of small, of the world (Rosa, 1950).The common names weak teeth,Palatines and vomer toothless. for the two species of Auxis in Japanese waters Dorsal fins well separated. Dorsal interspace have been divided to associate the proper com- slightly greater than half the distance between mon names to each.Additional common names origins of first and second dorsals. as they were encountered in the literature were added to the list compiled by Rosa. The names "Vertebrae 20+19 = 39, including urostyle. capitalized are in more general use. First haemal arch on 8th vertebra; first closed haemal arch and first haemal spine on 21st 1. 3 General variability vertebra. Haemal canal borne away from body of vertebra by pedicles Lof Starks (1910) 1. 3. 1Subspecific fragmentation epthaernal processes of Kishinouye (1923ff. (races, varieties, hybrids) "Body naked, except for corselet of scales. The meristic counts of Auxis thazard as Corselet along lateral line extends beyond ver- reported by several authors are given in tical through posterior end of second dorsal. TableI.Table II gives the comparison of Corselet 16-18 scale-rows wide below origin of meristic counts of A. rnaru, A. !e1nosoma, second dorsal fin.Lateral line more or less and A. thynnoides. undulating, without any pronounced arch. "Body markings consist of 14-16 dark, nearly vertical bars over bluish background above lateraf line.Bars often broken into spots.Dark continuous band over top of head and along dorsal margin of body.The band more or less uniform in width to end of second dorsal, whence it narrows posteriorly to base of caudal fin.Body below lateral line silvery white and free of markings or spots". Fig. 3 shows a sketch of the corselet formation found In the two types of Auxis (from Matsumoto, 1959: Figure 18). In discussing the difference in number of scale-rows between the smaller long- corseletted frigate mackerel of the Philippines and the larger specimens taken in Hawaiian waters, Matsumoto (1960) concluded from an analysis of the regression of number of scale rows on fish length that the number of scale- rows increases as the body length increases (Fig. 4).Thus, the variation in corselet width between the Philippine and Hawaiian specimens represents growth rather than a species difference. 1,2 3 Standard common names, vernacular names The common names most closely associ- ated with A. thazard in the Pacific are given 247 1:7

Fig. 3Sketch of Auxis showing corselet formation (from Matsumoto, 1959)

Io o 8 PHILIPPINE SPECIMENS 6 £ HAWAIIAN SPECIMENS

90 200 210 220 230 240 250 260 270 280 290 TOTAL BODY LENGTH IN MM. Fig. 4Regression of the number of scale-rows on total body length of Auxis thynnoides (from Matsurnoto, 1960)

28 1:8 FIb/S51 Frigate Mackerel

Country Common names Australia FRIGATE MACKEREL, Leadenall

Canada FRIGATE MACKEREL Hawaiian Islands FRIGATE MACKEREL, Keokeo, Mexican skipjack Japan Auxis sp. SDAGATSUWO A. thazard = A, hira RIRA SEDA, Hirasdakatsuo, Hiramejika, Obosogatsuwo, Shibuwa, Soma, Suma, Oboso (Hirasohda, Hiragatuo, and Hiramedika are variations in spelling of some of the above names) A, thyrmoides = A. mai-u MARUSDA, Marusdakatsuo, Marugatsuwo, Marumejika, Magatsuwo, Manba, Mandara, Chiboh, Dainalpo, Nodoiro, Rolisoku, Subota, Uzawa, Mejika, Soku, Soda, Subo (Marumedika, Marugatsuo, Magatsuo and Dainanbo are variations in spelling of some of the above names) Other nanie mentioned by Rosa (1950) are Kogatsuo, Fukarai, Kobukura

Mexico BONITO

New Guinea (Netherlands) Deho

Philippine Islands FRIGATE MACKEREL, Manko, Mangko (Mai-mao, Samal, Visayan, and Tao Sug) Note: The Philippine dialects are shown in parentheses

United States FRIGATE MACKEREL In respect to the origin of the common name in the United States, Goode in 1884 (p. 306) wrote,"The Frigaté Mackerel has been observed in the West Indies, and other parts of the tropical Atlaritie, as well as on the coast of Europe.In Great Britain it is called the 'Plain Bonito,'It is not unusual in the Bermudas, where it is called the 'Frigate Mackerel,' a name not inappropriate for adoption in this country, since its general appearance is more like that of the Mackerel than the bonito, while in swiftness and strength it is more like the larger members of this family,"

2L9 FIb/S51 Frigate Mackerel 1:9

Table I Comparison of meristic counts of Auxis thazard

Anatomical fe atures Hawaii Japan So. Calif. Philippines Hawaii (Jordan and (Kishìnouye,(Barnhart, (Wade, 1949) (Matsumoto Evermann, 1923) 1936) 1960) 1903) A. hira

First dorsal fin X X-XI X X-XII XI Second dorsal fin 12 12 12 10-12 10 -.12 Dorsal finlets 8 8 8 8 8

Anal fin 13 13 13 - LI,8-11 13 Anal finlets 7 7 7 7 7 Gill rakers 30+10 9+30 9-10+1+27-32= 37-439-10+1+28-31=39-42 Vertebrae 7.0+19 20+19 Branchiostegais 7 7

Table II Comparison of meristic counts of Auxis maru, A. tapeinosoma, and A. thynnoides Anatomica1 features A. maru A. tapeinosoma A. thynnoides Japan Philippines Hawaii (Kishinouye, (Wade, 1949) (Matsumoto, 1923) 1960)

First dorsal fin IX-X X-XI X-XI. Second dorsal fin 11-12 10-12 10-11 Dorsal firilets 8 7 8 Anal fin 13 II, 10-12 12 -13 Anal finlets 7 7 7 Gill rakers 10+36 10-12+1+31-35= 44-.48 10-11+1+32-36= 43-48 Vertebrae 2 0+19 Z 0+19

250 FIb/S51 Frigate Mackerel 2:1

2 DISTRII3UTION in 1931 from Job, Sulu Province. Recent records made by biologists of the Philippine ¿.1 Delimitation of total area of distribution Fishery Program include, in addition to the and ecological characterization of this above localities: Maya, Danao, and Cebu City, area Cebu Island; Bohol Iland; Zamboanga City, Davao, and Margosatubig, Mindanao; and In the compilation by Rosa (1950)the Iloilo City, Panay Island. Previously Auxis geographic distribution of A. thazard is given tapeinosoma has never been recorded from the as follows: Philippines, but during the past year specimens In the Nort1 Pacific Ocean; 'Coast of the have been collected at Siocon Bay and United States as far north as San Pedro on the Zamboanga City, Mindanao, and Batangas Bay, coast of California, Hawaiian Islands, coast of Luzon." Mexico around Cape Corrientes, coast of Costa Rica, Panama, Philippines, Formosa Islands, 2.2 Differential distribution coast of China around Ningpo and southern Manchuria, Ryukyu and Bonin Islands, coast 2.2.1 Areas occupied by eggs, larvae, of Japan as far north as Hokkaido in the Pacific and other junior stages; annu- Ocean and Sea of Japan, coast of Korea, rather al variations in these patterns uncommon in U.S.S.R. waters around and seasonal variations for Vladivostok." stages persisting over two or more seasons. Areas occu- In the South Pacific Ocean, Rosa lists A. pied by adult stages: seasonal thazard as distributed around the coast of the and annual variations of these Territory of Papua, New Guinea, and along the eastern coast of Australia as far south as Wade (1951) pointed out in his workon the Tasmania. Philippine tuna and tuna-like larvae that the- greatest catch of larvae of Auxis sp.was made Kishinouye (1923) states that Auxis has a during the months of January, February, and wide distribution in temperate and tropical March. During the remainder of theyear, the waters. collection was meager. Matsumoto (1960) noted a new distribution Wade also mentioned that small juvenile record for the long-corseletted A. thynnoides Auxis begin to appear on the nia rket in late from Hawaiian waters. He stated that 21 of November and are found in increasing numbers these long -corseletted Auxis were taken from until January and February. They decreasein the same school together with five short- quantity thereafter and are not found after May. corseletted frigate mackerel (A. thazard). The marketed juvenileswere taken in both The catch was made from the research vessel Batangas and Balayan Bays, whichare well "John R. Manning" of the Pacific Oceanic protected. Fishery Investigations (POFI)1Jby pole- and-li ne fishing7 one mile offshore, two Strasburg (1960) reported thàt the larvae miles northwest of Cape Kaea, Lanai, of frigate mackerel were infrequentlycaptured Hawaii.Mat surnoto remarked that at the surface during the day, butwere often although the long- and short -corseletted taken there in numbers at night. Furthermore, Auxis are known from both sides of the the captures of frigate mackerel larvaewere Pacific, only the short -corseletted form much greater in the 0-60 m plankton tows than has been reported previ ousl y from the in the surface tows. central Pacific Ocean. The distribution of Auxis sp. in Philippine From studying a large number of recently waters is given by Wade (1949).11e stated hatched larvae of Euthynnus and Auxismeasur- "In Philippine waters Dr. Herre (1940) has ing 3 mm to 4 mm in total length,Matsumoto recorded Auxis thazard from Nasugbu, and (1959) hypothesized that localities where larvae Balayan Bay, Batangas Province, Luzon, and of this size occurred represented the actual spawning sites.He deduced that larvae of 1/ Now the U.S. Bureau of Commercial Fisheries Biological Laboratory,Honolulu, Hawaii

251 2:2 FIb S51 Frigate Mackerel about 3 mm like the eggs which precede 2. 3 Behavioristic and ecological determi- them, are planktonic and that their dis - nants of theeneral limits of distri- placement from the spawning site was due bution and of the variations of these to ocean currents. Thus with the exception limits and of differential distribution of a few areas where ocean currents are Okachi (1958) studied the frigate mackerel strong, the displacement of tuna larvae taken in the Japan Sea.His results indicated from their actual spawning sites is rela- that the lower limit of water temperature for tively insignificant.Of the Auxis, occurrence of Auxi may be about 12 C Matsumoto concluded that the spawning (53. 6 F), He found that there is a slight sites may be near land masses, but its increase in the catch in summer after the water spawning sites also include oceanic temperature has risen above20°C (68. 0°F), situations, as indicated by larval cap- but during the period of southward movement, tures as much as 900 miles from land when peak catches occur, the water tempera- in the Pacific Ocean, Part of Matsu- ture has dropped to about16°-l9°C (60.8° to moto's (1959) figure 31 (Dana Report 66.2 F). No. 50) is shown in Fig. 5 and gives the localities of capture of Auxis larvae by According to the table constructed by the 'Dana" and a research vessel of the Kishinouye (1923) showing the water tempera- Pacific Oceanic Fishery Investigations ture in which scombroid fishes are found, A. in the Pacific, hiraandA. maru occupy temperatures ran%ing from about l4Tabout 25°C (57.2° to 77. 0 F).

252 FIb/S51 Frigate Mackerel 3:1 3 BIONOMICS AND LIFE HISTORY 3.1. 4 Fertilization (internal, external) 3.1 Reproduction Fertilization is external.It is presently believed that scombroid fishes expel their 3.1.1 Sexuality (hermaphroditism, reproductive elements into the water when heterosexuality, intersexuality) mating. The frigate mackerel is heterosexual, as 3.1.6 Spawning is true with all the other scoxnbroicls. However, there are published reports of hermaphroditism - Spawning seasons (beginning, occurring among scombroid fishes. Nakamura end, peak) (1935) recorded and described a hermaphroditic skipjack, while Uchida (1961) reported on two Schaefer arid Marr (1948) state that the separate instances of hermaphroditism in skip- capture of juveniles indicates that A. thazard jack taken in Hawaiian waters. Thus, it is not spawns in Central American Pacific waters unreasonable to expect herrnaphroditisrn to during the early spring. occur in Auxis. The earliest record of the spawning habits There are no externally visible reproductive of the Auxis sp. in the Pacific is given in an organs which distinguish the male from the fe- account by Kishinouye (1923). He states that male of the epecice. the species called A. hira seems to spawn in ,the summer and that nearly ripe reproductive In general, the scombroid fishes have repro-elements are found in the adults in August. ductive organs that are paired and eloügated on the roof of the abdominal cavity. These organs Of the Auxis occurring in Philippine waters, are suspended in a fold of the peritoneum and Wade (1951) concluded that the principal spawn- extend along almost the entire length of the body ing activities occur during the winter and that cavity. The organs on both sides are nearly scattered spawning takes place the remainder symmetrical. Kishinouye (1923) states that the of the year. reproductive o1gans of the Auxis, both male and female, extend posteriorly along the side of the On spawning of the A. maru, Kishinouye anal fin.This posterior extension, he states, (1915) remarked that this species spawns is caused by the narrowness of the abdominal during the summer months. cavity. Presumably, Auxis alsospawn in Hawaiian 3.1.2 Maturity (age and size) waters.In his report citing an instance of natural mass mortality of larval frigate mack- Tester and Nakamura (1957) noted that the erel in the Hawaiian Islands, Strasburg (1959: frigate mackerel taken off Kaneohe Bay, Oahu, Fig. 4) showed the length frequency distribu- Hawaii, which averaged about 1-WZ pounds in tion of 2, 561 specimens. These ranged in weight, had gonade that were mostly in the size from about 2.2 mm to about 8.3 mm in maturing stage or nearly mature stage of de- total length.In section 2.2.1, Matumoto velopme nt.Included in their catch was one (1959) hypothesized that localities where larvae male which weighed 2.-1/2 pounds with gonads of about 3 mm to 4 mm in total length oc- which they 4assed as being in the "mature" curred could possibly be the actual spawning stage of development. siteoi the adult.Although Strasburg noted 3.1. 3 Mating (rnonojaiicui, polyga - that all his specimen s were past the critical mous, promiscuous) yolk-sac stage, it argues by Matsumoto's hypothesis that the smaller frigate mackerel No information is available on the mating larvae perhaps averaging about 3-4 mm are habits of the frigate mackerel, but in general recently hatched fish.Strasburg gives the it is believed that sbombroid fishes release dates of capture cL these larval frigate mack- their sexual products directly into the water erels as between July 11-13, 1957.Thus, it without pairing of the male and female as such. can be concluded that some spawning occurs The mechanism which triggers the reproductive during June or July in Hawaiian waters. activity, that is spawning and fertilization, is still unknown. Wade (1951) found that in the Philippines the greatest catch of Auxis larvae occurred 253 32 FIb/S51 Frigate Maçker

90° 120° 50° 180° 150° 20° 90° 60°

60° 60°

300 30°

0° £ 0°

300 30°

£ CAPTURES BY POF1 VESSEL CAPTURES BY DANA B OTHER DANISH VESSELS (NO.) SURFACE WATER TEMPERATURE °C

600 60° 900 120° 1500 ¡80° 150° 120° 90° 60°

Fig05 Localities of capture of Auxis larvae in the Pacific Ocean by the "Dana and POFI vessel (from Matstimoto, 1959)

25'4 FIb/S51 Frigate Mackerel 3:3 during the months of January through March. 3.2 Larval history The catch during the rest of the year was very meager. He states that small juvenile Auxis 3.2.1 Account of embryonic and begin to appear on the market in late November juvenile life (prelarva, and become more abundant until January and larva, postlarva, juvenile) February, after which time they begin to de- crease in quantity.After May, the juveniles According to Matsurnoto (1959) the Auxis are not found on the market. From the timeof larvae with which he worked exhibited some occurrence of larvae and juveniles, it may be variation in pigmentation and since there is a possible to conclude that spawning occurs possibility that this variation may be due to during the fall and winter months in Philippine the presence of two species of Auxis, he waters. described two separate series of larvae. These were designated as types land II, and 3.1.7 Spawning grounds the validity of this separation was discussed in his report. - Oceanic (surface,bottom) The descriptions of the type I and type II Juvenile s of Auxis are taken in fish traps larvae are quoted from Matsumoto (1959), and and several types of local nets close to the his figures, from 19 to 29, are reproduced shore and in open waters of well-sheltered here in Figs. 6 to 16. Batangas and Balayan Bays (Wade, 1951). From these findings, Wade concluded that the Auxis type I. adults of Auxis spawn in protected, more or less shallow areas, fairly close to land. 11(l) Two or more rows of chromatophores in the region of the caudal peduncle. In this In his Dana Report of 1959, Matsumoto particular series, even the smallest specimen, discussed the spawning areas of the Euthynnus 4.5mm ('ig. 6), has 3 distinct rows of and Awds as indicated by larval catches. He close-set chromatophores along the middorsal, pointed out that the genus Euthynnus spawns in midlateral, and midventral lines of the caudal the vicinity of land masses judging from the peduncle. The chromatophores increase in localities in which the adults and larvae were number with growth of the fish, and by the captured, and this may be said also for the time the species has attained 11.2 mm (Fig. Auxis.However, because spawninsites of 10), 1 or 2 rows of chromatophores are pre- the Auxis also include oceanic situations, as sent along the dorsal midline of the body from deduced from- larval captures as much as 900 the origin of the drsa1 fn to the caudal miles from land, the genus Auxis -may be peduncle.The number of chromatophores considered a more pelagic spawner than the along the midlateral line also increases, and Euthynnus. in a 13.2 mm spectn (Fig. li) the chromatophores have moved internally toward the verte - 3.1.8 Egg: Structure, size, hatching brai column. At about 14. 0 mm a single row type, parasites and predators of dermal chromatophorea is seèn along the

midlateral i - e1tht1y posterior to the tip of Matsumoto (1958) discussed the observa- the pectoral fin.Thio row gradually increases tions made by Sanzo (1932, 1933), on the devel- in width and length until it appears as a wide, opment of the embryo in the eggs of Orcyus dark band, which is distinctly noticeable In the thynnus and Orcynus germo.(Matsumoto 25 mm specimen (Fig. 12). believes that the formercould be the bluefin (2) Pigment spot at the symphysis of the tuna and the latter could be either yellowfin pectoral gird1. This spot, common to both or albacore.)Undoubtedly, the eggs, after. Auxis and Euthynnus, is present in nearly all they are expelled and fertilized, remain of the specimens examined.It usually consists planktonic and float with the current. of a single large chromatophore in specimens Matsumoto deduced from other studies on below 20 mm. In larger specimens, however, eggs of pelagi c species of fish that the eggs this spot may be represented by 2 to 4 small, of tunas probably have an incubational period closely grouped chromatophores. of not more than four days.

255 3:4 Ftb/S51 Frigate Mackerel

! iIRfIIt(ittitt(if(i.iirnx

I MM, Fig. 6Auxis type I, 4. 5 mm (from Mats umoto, 1959)

I MM. Fig. 7Auxis type I,5. 5 mm (from Matsu.moto, 1959)

256 PÏb/S51 Frigate Mackerel

IMIt Fig 8Auxis type I, 7.O5im. (fróm. tßumoto, 1959)

74_ *4 ,' * ,' (X

(MM.

Fig. 9Auxis type I, 97thr: (fro L motp,1959)

257. 3:6 FIb/S51 Frigate Mackerel

1MM. Fig. loAuxis type I, ll.Z mm (from Matsuxnoto, 1959)

FIg, 11Auxis type I, 13.Z mm (from Matsumoto, 1959)

258 FIb/S51 Fri ate Macker

Fig. 12Auxis type I, 25 0 mm (from Mats umoto, 1959)

Fig. 13Auxis type II, 3. 5 mm (fom Matsumoto, 1959)

I MM. Fig. 14Auxis type II, 3. 7 mm (from Matsumoto, 1959) 259 3:8 FIb/S51 Frigate Mackerel

I MM. Fig. 15Auxis type II, 5.Z mm. (from Matsumoto, 1959)

I MM. Fig. 16Auxis type II, 7.2 mm (from Matsuxnoto, 1959)

260 FIb/S51 Frigate Mackerel 3:9

Number of spines (less than 9 or 10) myomere count is identical with that found in in the first dorsal fin. The first dorsal spines type I. are insufficiently developed for comparative purposes in specimens below 7 or 8 mm. The "The 3.7-mm specimen (Fig. 14), which 9.7 mm specimen (Fig. 9), however, pos- was earlier identified as A. thazard (Matsurnoto, sesses a first dorsal fin composed of 9 well- 1958), appears similar to the 3.5-mm specimen developed spines which closely resemble that and has therefore been placed in this series. of the adult.The first and second dorsal fins are widely spaced, and the initial development "A slightly larger specimen, 5.2mm of 7 additional small spines are noticed between (Fig. 15), also has the same characteristics the end of the first and origin of the second as the 3. 5-mm specimen, except for the dorsal fins.These spines do not develop to pigmentation on the posterior part of the body. any great length, as noticed in the 25-mm There are 3 very closely spaced chromatophores specimens, but are still distinctly noticeable on the midventral line of the caudal peduncle on larger juveniles up to about 50 mm. Except region, and 4 more widely spaced chromato- for the anterior 2 or 3 spines, which later de- phores farther forward. velop as part of the first dorsal fin of the adult, these interdorsal spines ultimately become "Several changes occur in the 7.2-mm imbedded beneath the outer layer of skin. specimen (Fig. 16).The first dorsal fin consists of 5 spines, and the second dorsal fin Number of chromatophores in the first is represented by about 11 rays.The anal fin dorsal fin.Generally, the first dorsal fin of also shows signs of development, and about 7 juvenile Auxis is very lightly pigmented and is rays can be distinguished.The anal finlets, almost colorless. The first signs of pigmenta- like their dorsal counterparts, are hardly tion on this fin appear rather late, at: about noticeable. The caudal fin is quite advanced 11.0mm and the 11.2-mm specimen illus- in development, and its posterior margin is trated here has only 3 large chromatophores. beginning to fork. The ventrals are present, The 13.2-mm specimen also shows few but they are still very small. chromatophores. Beyond this size the number of chromatophores seems to increase with "In general only minor changes in pigmen- growth, but at no stage is this pigmentation tation are evident. Two very close-set chroma- conspicuous. The chromatophores themselves tophores are present on the dorsal edge of the are scattered almost evenly throughout the fin caudal peduncle, and 2 more similar ones are membrane, as shown in the 25. 0-mm specimen noticeable opposite them on the ventral edge. (Fig. 12). Anteriorly, 3 more well-spaced chromatophores are present along the bases of the anal finlets. Auxis type II. series stops at about8 mmand all "Type II refers to a series of larvae, specimens above this size are referable to measuring from 3.5 mm to 7.2 mm which type I." lack chromatophores along the roidlateral line in the caudal peduncle region.This lack, Matsumoto points out one Important however, is not always consistent, and on some observation in discussing the species difference specimens chromatophores are missing on one of the type I and type II larvae of Auxis.This side only.The smallest specimen (Fig. 13) is the extreme inconsistency of pigmentati9n on has a single darkly pigmented spot at the the midlateral line.In many of the specimens symphysis of the pectoral girdle and chrornato- he examined, there were from 1 to 5 chroma- phores on both the dorsal and ventral edges of tophores on one side of the body, but none on the body in the caudal peduncle region.Unlike the other side. He states that such a wide the type I specimens, only one chromatophore variation in pigmentation between the two sides is present on the dorsal midline of the caudal of the same fish renders the separation of peduncle region. A long series of 9 well- Auxis into types I and II rather doubtful. He spaced chrornatophores is present along the states that on the basis of this variation and entire ventral margin of the body.The mid- also on the fact that the type II series stopped brain is'spanjely pigmented and the midsection at about 8 mm., one may conclude that the two of the lower jaw has no pigmentation. The types are merely variants of a single species. 261 3:10 FIb/S51 Frigate Mackerel

In the Indo -Pacific region, Auxis larvae The vertebral count of the specimens have been captured in waters with temperatures examined by Schaefer and Marr agrees with that ranged from ¿2.5° C(72.5° F) to 29° C Kishinouye (1923) and Frade and deßuen (1932) (84.2° F).The coldest water in which Auxis but disagrees with Starks (1910).They found larvae were taken occurred off the eastern that in a 72 mm specimen the haemal arch coast of Australia (Matsumoto, 1959). was first noted to close on the 18th vertebra. This is in disagreement with the report by According to Clemens (1956), larval Kishinouye, who states that the first closed scombrids most frequently captured under a haemal arch occurs on the first caudal vertebra night light in the tropical eastern Pacific are (21st vertebra). Because of this discrepancy, the frigate mackerel. He states that these Schaefer and Marr concluded that the specimens larvae are more numerous and widely distri- with which they worked may, therefore, be buted than the Euthynnus larvae. The larval juveniles of an undescribed species. frigate rrckerel outnumber the larval ELhynnus by about 300 to 1 in night light Schaefer and Marr concluded from the samples collected in areas where larvae of vertebral count, the great length of the right both of these scombrids occurred. lobe of the liver, the presence of a caudal keel, and the absence of an air bladder that the Descriptions and comparisons of morpho- juvenile scornbrids they examined belong to the logical features of the juveniles of A. thazard family Katsuwonidae. Because of the large are given by Schaefer and Marr (1948).In interspace between the dorsal fins and low ray their work, they recognized that different count of the first dorsal, as well as the absence species of Auxis may occur in different parts of the elaborate "trellis" of the vertebrae, they of the world, but since the solution to the deduced that the specimens belonged to the problem of specifically identifying the species genus Auxis rather than Euthynnus or with which they worked was beyond the scope Kats uwonus.Thus, specific identification must of their investigation, they referred to the await examination of adult specimens from the juveniles as A. thazard. area. The juveniles were captured in Central Herald (1951) reported on the presence of American Pacific waters off Costa Rica and pseudofins on the caudal peduncle of juvenile northern Panama. These fish were taken Auxis. He found that "two of the three solid with dip nets at night under flood lights.The ridges which; are conspicuous along the side of locations and dates of capture 'are given in the tail of adult Auxis actually develop as small, Table III. unstriated, fin-like structures." He counted usually 11 soft rays in each Auxis pseudofin and Five additional specimens examined by as many as 14 rays were present. He says that these investigators were supplied by Dr. J. T. these structures have no outstanding anatomical Nichols, arid these were taken under night significance.The lengthsthich frigate mack- light on March 24, 1941, at 04°01' N,8O°26' W. erel attain before the replacement of these The description of these representative pseudofins by solid ridges takes place is not juveniles is quoted from their work (p. 266). definitely known. Table III Localities of capture of A. thazard in 1947

Date Position of station Number caughtTotal length of specimens (mm.)

March 1808°20' N.,, 84°lO' W. ¿ 67, 68 March 1909°43' N., 85°54'W. 52 ¿1 to 53 May 7 08°7' 30" N., 83°8' 30" W. 3 23 to 41 May 17 09043c N., 85°54' W. i 42

262 FIb/S51 Frigate Mackerel 3:11 "In the smaller specimens the prominent mackerel refused food until the second day, areas of pigmentation are on the upper and at which time they started to compete for lower jaws, above the snout, around the food with the other fishes such as dolphinfish postero -ventral margin of the orbit, on the (Coryphaena), jacks (Caranx), pompano upper opercu.lum, between the orbits, along (Trachinotus), threadfins (Polydactylus), and the midline of the body, along the bases of pomacentrids (Chromis).Clemens believes the dorsal and anal fins including the finlets, this behavior of the frigate mackerel suggests and around the posterior end of the urostyle. that they had learned to eat the unnatural food Large chromatophores in the peritoneum that was being offered by watching the other show through the body wall along the upper species feeding on it.The food offered half of the body cavity. None of the fins or included living planktonic organisms, ground finlets bears pigment spots, with the exception fie sh of anchovetas (Centengroulis mysticetus), of the first dorsal.The first dorsal bears a yellowfin tuna (Neothunnus macropterus), few scattered chromatophores, largely distri- oceanic skipjack (Katsuwonus pelamis), and buted along the spines. However, the first dolphiníish (Coryphaena hippurus), particles dorsal in general appearance is virtually of coagulated fish blood, and doiphinfish eggs. colorless... Clemens adds that competition for food Schaefer and Marr found that with increas- appears to be of fundamental importance. He ing size, the local areas of pigmentation noticed that in a tank with a large number of expand. They state (p. 267), '11n our largest fish that splashed and moved about the tank at specimens the head is well pigmented. The a high rate of speed, voraciously striking at dorsal hai f of the body is uniformly dark. everything in sight, the frigate mackerel soon This dark area extends below the midline on commenced feeding. the caudal peduncle. The chromatophores in the peritoneu.m are no longer visible through - Rates of: development and the thickened body WaU, and the ventral sur- survival face is unpigmented. Even in our largest specimens none of the fins is heavily pigmented; In reference to growth of postlarval Auxis, the caudal is mor e pigmented than the others. Clemens (1956) noted that the Auxis had a more rapid rate of growth than the Euthynnus.Of An interesting discussion on gill raker five postlarval Auxis placed in an aquarium for counts in the juvenile A. thazard is also given observation, he stated that three died several by Schaefer and Marr, They state that the gill hours later from injuries received in handling. rakers on the most anterior gill arch of their The remaining two measured 20 and 30 mm in smallest specimens are very tiny projections total length, and these survived for six days. and are first apparent near the angle of the The smaller frigate mackerel grew about 40 mm. arch. As the fish increase in size, the rakers during its six days in captivity while the larger near the angle of the arch increase In length fish grew an estimated 46 mm in six days. and new rakers are added distally on each arm. They further state that the full complement of - Periods of: development and rakers is apparently attained at about 50 min survival total 1 ength. - Feeding Strasburg (1959) reported on an instance of natural mass mortality of larval frigate mackerel in the Hawaiian Islands. He noted that By examining the stomachs of juvenile there were two distinct types of larval frigate A. rnaru, which were recovered from the mackerel in the preserved plankton collection stomachs of yeliowfin and skipjack, made in the vicinity of Lanai Island, which is Kishinouye (1924) foiuxl that like the juveniles one of the smaller members of the Hawaiian of skipjack, the food of juvenile A. maru con- chain. One type was clean cut and of normal sists of larval copepods and decapods. appearance, while the other type was imperfect with signs of physical deterioration. He hypo- Clemens (1956) observed the feeding thesized that these types represented fish behavior of larval sconibrids reared in ship- which were alive and dead, respectively, just board aquaria, He stated that the frigate prior to capture,In a simple experiment, he

263 3:12 FIb/S51 Frigate Mackerel allowed several fresh, dead specimens to mers, are feeding on the juveniles of other decompose in dishes of sea watery while sev- kinds of fish, it is not unusual to find as many eral other fresh, dead specimens were pre- as twenty or thirty individuals in the stomach served in formalin,By comparing the of one fish. However, when the Plecostean appearance of the two types of larvae he found fishes are feeding on the juveniles of their in his plankton collection with the preserved own kind, only a few specimens at most are and decomposed specimens, he concluded that found in any one stomach. large numbers of the larval frigate mackerel he had collected were dead before capture. 3.3 Adult history The definitive cause of death could not be determined. He noted that there were no signs 3.3.2 Hardiness of predation, disease, or parasitism, and starvation could not be definitely excluded as a Kishinouye (1923) pointed Out that the salinity factor. He tentatively hypothesized that the of the water most suitable for scombroid fishes mass mortality was due to the passage of the differs very greatly for different species. For larvae through an area having marked dis con- the fishes of the family Scombridae and tinuities in its surface water temperature. Cybiidae, he gave a density range of 1,022- 1.025, while for the Plecostean fishes, which - Parental care he claims prefer water of a higher density, he gave a density range of 1.025-1.027. How- The eggs, larvae, and juvenile stages of ever, he added that Auxis are sometimes the frigate mackerel are, like the adults, found in littoral waters of low density. completely pelagic.There is at present no evidence that the adult of the species carfor 3.3. 3 Competitors the eggs or young. In general, the frigate mackeiel live in -Parasites and predators competition with other tunas,mackerel, and bonitos during all stages of their life.In Mead (1951), working with pos tlarval tuna section 3.42 are listed some of the organ- from the Pacific Coast of Central America, isms found in the stomach of frigate mackerel. found two juvenile Auxis, 79 and 117 mm. in Examination of reports on food studies of big- fork length, in the stomach of a large yellowfin eye, yellowfin, and albacore indicates that caught on May 6, 1949, at 11°40' N. latitude, most of the organisms Auxis feed on are also 91°O0 W. longitude. He tentatively identified a part of the ciet of these tunas (King and these two specimens as A. thazard on the basis Ikehara, 1956; Iversen, 1961). of gill raker count. It may be concluded that most pelagic Kishiriouye (1923) reported that he received fishes are potential competitors of Auxis. several immature specimens of A. nia ru which were obtained from the stomach of striped 3.3.4 Predators bonitos, caught off Awakunijima, Okinawa-ken (Ryukyu). They ranged in size from 11 to 17 cm. In his study of the spearfishes of the in length. The largest specimen resembled the central Pacific, Royce (1957) found that adult form, but of the smaller specimens, several tunalike fishes, some identifiable as ranging from 11 to 13 cm. in length, he stated Auxis, were present in the stomachs of that they were remarkably slender,In the striped marliñ (Makaira audax) taken in equa- small specimens, the skin wasmore or less torial waters. Nakamura (1942), in examining damaged by the gastric juice and the markings the food contents of 163 stomachs of black were not seen, but on the largest specimen, he marlin (Makaira ampla) taken in the east noted that there seem to be some transverse bands. Philippine Sea, found that 53 stomachs con- One interesting observation about the tained squid, li contained Leiognathus, 12 predator-prey relationship among the scorn- contained Balistes, 11 contained Auxis, and broids is given in a work by Kishinouye (1926). lesser amounts of some 9 other genera of fish. He states that when the mature fish of the In a report published in 1936 dealing with Plecostei, which are among the fastest swim- thefood habits of yellowfin tuna (Neothurtnus

26L FIb/S51 Frigate Mackerel 3:13 macropterus) taken in the Gelebes Sea, not numerous, although sometimes they occur Nakamura comrr nted that it is not known in large batches. whether there is a point of satiation in the feeding of the yellowfin, but in the stomach of Kishinouye also discusses internal para- a yellowfin 137 cm in length, he found three sites of the scombroid fishes and he says that specimens of Auxis sp. which averaged about these are chiefly trematodes and nematodes, 30 cm in length along with various other living in the alimentary canal, the circulatory items. system, muscles, and tissues of the viscera. He noted that species of Distoma use From the examination of the stomach con- Acanthocybium, tunnies, and bonitos as hosts. tents of yellowf in (Neothunnus macropterus), skipjack (Katsuwonus pelamis),oceanic 3.3.6 Greatest size bonito (Euthynnus yaito), and dolphin (Coryphaena hippurus), Ronquillo (1953) con- Tinker (1944) states that the frigate mack- cluded that tunas apparently do not choose erel in Hawaiian waters is smaller than the their food, but eat any swimming animal skipjack and may reach a weight of about 10 available.Fish evidently is the chief food pounds. However, in schools, they seldom item of the tuna. Among larvae and juvenile exceed 5 pounds in weight.Gosline and fishes frequently appearing in the stomachs of Brock (1960) state that the Hawaiian frigate the tunas and dolphins he examined were mackerel is generally less than 10 pounds in Acr onurus, Caranx, Holocentrus, Gempylus weight. Fish (1948) is of the opinion that the Auxis, Dactyloptena, Trichiurus, balistids, frigate mackerel does not get over 5 pounds. monacanthids, tetraodontida, triacanthids, Kishinouye (1923) states that the A. hira chaetodontids, and bramids. The specimens grows to a weight of about 1. 5 kg(about 3. 3 of Auxis were among the larger fish included pounds), while of the A. ma ru, he says that in the food item. Ronquillo stated that a few this fish is the smallest species in his order specimens of Auxis about ¿50 mm in fork Plecostei and grows to a weight of about 640 g length were found in the stomachs of yellowfins (about 1. 4 pounds). 674 mm in fork length. 3.4 Nutrition and rowth From his study on the food of the tunas, Kishinouye (1917b) f oxnd that many juveniles 3.4.1 Feeding (time, place, manner, of tunas can be collected.In the stomach of season) one yellowfin, he found a juvenile bigeye swallowed together with flying fish and several In discussing the habits of the scombroids specimens of A. maru.Another yellowf in In general, Kishinouye (1923) stated that they stomach had a juvenile albacore about 10.8 generally swim to the shallower strata of inches long along with some A. rnaru. water at night and return to the deeper layer in the daytime. He believes that they are In a comparative study of food of bigeye probably following the movement of the and yellowfin tuna in the central Pacific, plankton and also the movement of those King and Ikehara (l956:table 11) list A. thazard fishes that feed on the plankton. occurring in 2.7 percent of the yellowfin stomachs examined and in 1.2 percent of the Imamura (1949) discussed the manner in bigeye stomachs examined. which A. maru andA, lira feed. He main- tains that these fishes use their caudal fins 3.3.5 Parasites and diseases to hold their position in the swift currents and in this way capture their food, which drifts Of the scombroid fishes in general, down to them. In the morning and evening Kishinouye (1923) stated that external para- and also during perIods of cloudy weather, sites are mostly copepods and trematodes. they sometimes migrate away from the swift He found that these are usually attached to currents in search of food and school near the upper surface of the pectoral fin, to the the surface. inner side of the opercie, to the gilllamellae, in the nasal cavity, and in the mouth cavity. From his study on the ecology of teleosts He stated that, in general, these parasites are in Japanese waters In relation to brain

265 3:14 FIb/S51 Frigate Mackerel morphology, Uchihashi (1953) concluded that Imamura discusses the migration of the A. tapeinosorna seeks food by sight and can two species of sdagatsuo, the marusdakatsuo 1so detect prey by their lateral line senses. (A. maru) and the hiras6dakatsuo (A. hira). He states that both species prefer high temper- 3 4. Z Food (type, volume) atures and live in the Kuroshio.Of the marusdakatsuo (A. maru), Imamura says Tester and Nakamura (1957) examined the that it is a coastal fish that prefers the swift stomach contents of two frigate mackerel currents around promnontories and enters the taken off Kaneohe Bay, Oahu, Hawaii, and bays i found that one c-ontained numerous crab schools. On the Pacific coast of The other Japan, they migrate as far north as Shiriya megalops and stornatopod larvae. Misaki in Aomori P'efecture (about 41° N.) stomach examined contained 8 crab megalops, and also enter the Japan Sea. numerous stornatopod larvae, 2 anomuran larvae, and a small octopus. These fish were Imamura states that the hiras5dakatsuo 33.2 and 36.6cm in length. (A. hira) has a body which is more flattened laterally than the marusdakatsuo and is more Kishinouye (1923) stated that Auxis sp. pelagic in nature.It livesaround islands and generally feeds on small plankton and small promontories and its habits are much like that fishes, such as Atherina, Sto1ephorus of the sumagatsuo (E. yaito).The hirasdakatsuo Spratelloides, and immature forms of do not form large schools and are sometimes Engraulis. seen mingled with the true skipjack. About the time of the autumn equinox (September 22 Okada (1955:137) states that the marusda, in the Northern Hemisphere), the schools which he calls A. tapeinosoma, "always lives which have been migrating northward turn far off the coast, in shoals, and feeds on south and begin their southward migration. small pelagic organisms anchovies, silvery anchovies, silversides and other small fishes." Kishiriouye (1923) reported that the Auxis approach close to shore during the warn-i 3.4:3 Relative and absolute growth seasons, often in very large schools. During patterns and rates the colder winter months, the fish swim in the deeper strata of water. No information is available on the relative and absolute growth pattern and rates of the Uchihashi (1953) made án ecological study adult frigate mackerel. What little Informa- of the Japanese teleosts in relation to the brain tion is available on the absolute growth rate morphology. He noted that the marusda (A. of juvenile frigate mackerel has been dis- tapeinosoma) is a type of fish that swims in cussed in section 3.2.1, Rates of: develop- groups during the night as well as during the ment and survival. day. 3.5Behavior Okachi (1958) found from his studies of the catch statistics of frigate mackerel taken in 3.5,1 Migration and local movements the Japan Sea that along the coast of the Japan Sea, west of Ishikawa Prefecture and on the Imamura (1949) states that in Japan the west coast of Kyushu, there are a number of general term skipjack (katsuo) includes four months when no catch is recorded, but he species. These are the magatsuo states that in general small quantities are (Katsuwonus pelamis), the sumagatsuo taken throughout the year. He assumes that (Euthynnus yaito), the hagatsuo (Sarda there are some schools which pass the winter orientalis), and the sdagatsuo (Auxis sp.). in these regions.While he was not able to He Bays that thesefish live in tr[1 areas detect a clear trend of northward migration which have, high water temperatureSand by examining the peak in the catch, he found migrate into Japanese waters with the an extremely clear trend of southward move- Kuroshio in the summer. ment of the frigate mackerel apparent in

266 Flb/S51 Frigate Mackerel 3:15

Aomori, Akita, and Yamagata Prefectures in southward movement, the schooling charac- October, west of Niigata to Yamaguchi and in teristics of the fish, differences in swimming Fukuoka, Saga, and Nagasaki Prefectures in depth, and whether or not their migration November, and in Kagoshima Prefecture in routes approach the coast. December whiçh produces the bulk of the annual catch (Lble IV: table 5 of Okachi,1958) In an analysis of the behavior of some marine teleosts, Uchihashi (1953) concluded Okachi further states that he is uncertain that A. tapeinosoma is a type of fish that is as to the reason for the small catch of frigate very quick in behavior and also noted that mackerel in the Japan Sea while the fish are the fish has phototaxis response. on their northward journey. He finds that the northward movement begins aroundJune and 3.5.2 Schooling is more active around July and August. At about this time, the force of the Tsushlma It is apparent from the reports contained Current flowing into the Japan Sea is also at in the literature that the schooling instinct its height, and he deduced that thé frigate of the frigate mackerel is very strong. mackerel move north in off-shore waters to- Nakamura (1937) reported that dense schools gether with the main stream of that current. of Auxis sp. migrate into the coastal waters From October, however, the schools that of Taiwan during certain times of the year. moved north come close to the coast because Shapiro (1948) reported that A. hira is abun- of the wind-driven currents headed toward dant in the Ryukyu Islands in mid-summer. Japan under the influence of the northerly to Shoals of hundreds of individuals were northwesterly seasonal winds which begin to reported to appear in the southwestern part predominate at about this time. Thus, he of Australia by Serventy (1941). concluded that the opportunities to enter the trap nets are increased. He does not dis- In Hawaiian waters, frigate mackerel are count the fact that there may be other differ- occasionally found mixed with schools of ences, such as in the ecology of the frigate Euthynnus yalto (Gosline and Brock, 1960). mackerel during the periods of northward and Mats umoto (19 60) has reported. capturing Table IV Mean catch of frigate mackerel by month and prefecture (from January 1952 to July 1957) Unit of catch: i,oqo kan(= 3.75 metric tons) Month Prefecture 2 3 5 6 7 8 9 10 11 12 Aomori 0.1 0.9 1.7 0.7 3.1 0.6 Akita - - - 0.1 0.6 1.1 1.3 1.7 0.4 Yarnagata -- -- - 0.1 0.1 0.5 0.1 - Ni igata 0.20.1 0.1 - 3.53.1 4.57.717.9 0.7 Toyarna 2.00.2 --- 0.1 0.40.4 0.536.9 100.560.3 I shikawa 0.3 - 0.10.1 - - 2.5l:.Z 4.15.510.5 5.7 Fukui 0.30.30.20.2 0.4 0.4 3.5 17.5 4.95.56.7 1.9 Kyoto 0.3 - 0.10.2 - 0.3 0.30. 0.55.110.9 7.7 Hyogo 0.1 - - 0.2 0.1 - 0.1 0.3 F0,30.7 0.5 Tottori 0.20.2 - - 0.1 0.1 0.6 2.35.11.3 0.3 Shi mane 0.30.10.202 0.3 0.3 0.30.8 1.52.97.5 0.5 Yamaguchi1.9 0.80.50.3 0.2 0.3 1.8 7.18.021.112.7 Fukuoka 0.1 - -- - 0.1 0.1 0.1 1.50.3 1.30.2 Saga 0.60.10.1 -- - - 0.1 - 0.1 0.80,5 Nagasaki 6.90.70.70.2 0.3 0.5 1.5 2.3 5.117.129.3Z7.7 Kurnamoto - 1.20.1 2.4 1.1 0.1 0.30.40.30.6 0.20.2 Kagoshi ma .34.25.517.019.2 24.238.217.311.312.114.114.9

267 3:16 FIb/S51 Frigate Mackerel both A. thazard and A thynnoides from the same school (see section 2.1). Matsumoto (1959:20) wrote, 'tIt is interesting to note that both long- and short-corseletted forms taken in Hawaiian waters were from the same school.Through correspondence with Dr S, Jones, Chief Research Officer at the Central Marine Fisheries Station, Maudapar Camp, South India, it was learned that two types of Auxis also occur in the Indian Ocean, and that they are frequently found together in the same school. Similar observations were also reported by Kishinouye (1915). Imamura (1959) states that A. lira found in Japanese waters do not form large schools. They are occasionally found mingled with skipjack. 3.5.3 Reproductive habits See sections 3.1.1, 3.1.3, and 3.1.6.

26g 4:1 FIb/S51 Frigate Mackerel

reported by Strasburg (1959). A summaryof 4 POPULATION (STOCK) his findings is given in section 3.2.1 under Periods of: development and survival. 4.1 Structure 4. 6 Relation of population to community 4.1.1 Sex ratio and ecosystem, biological production, etc. No information is available on the structure of the population in relation to sex ratio. How- As the Auxis is an open water form and ever, an account of changing sex ratio on the lives in an environment where many carni'ores fishing ground throughout the season is men- are present, it is most likely predation rather tioned in the work by Kishinouye (1923). He than competition for food that limits its abun- states that generally, among the scombroids, dance. Evidence of predation is apparent in the male fish arrive first on the fishing ground. many food studies made on tunas and spear- By the middle of the season, the sex ratio is fishes, and both juveniles and adult frigate nearly equal.The end of the fishing season mackerels fall prey to large predators. finds female fish predominating on the fishing ground. It has been hypothesized that marked dis- continuities in surface water temperature 4.1.3 Size composition may be responsible for mass mortality of larval frigate mackerel (Strasburg, 1959). In he summary of catches off Kauéohe Bay, (See section 3.2.1, Periods of: development Oahu, iawaii, Tester and Nakamura (1957) and survival). listed a total of 23 frigate mackerel taken between the period May 1951 to October 1954. Although the number of fish taken was small, this is perhaps indicative of the size composition of the population of frigate mackerel from this area.Tester and Nakarnura noted that the 23 frigate maëkerel averaged l-1/2 pounds and ranged from 1 to 2-1/2 pounds.

Warfe]. (1958) reported that the average weight of A. thazard and A. tapeinosOxfla taken from Philippine waters Is about 12 ounces. Of the frigate mackerels found in Australian waters, Roughley (1951) stated,"With the possible exception of the leaping bonito, the frigate mackerel is the smallest of the Australian tunas, its weight rarely exceeding 3 pounds." 4.4 Mortality, morbidity 4.4.2 Factàrs or conditions affecting mortality An instance of naturalrnass mortalityof frigate mackerel larvae in Hawaiian waters was

269 FIb S51 Frigate Mackre1 5:1

In a publication giving the morphometric 5 EXPLOITATION measurements of Pacific scombroids, Dung and Royce (1953) recorded that the frigate 5.1 Fishing equipment mackerels from the Hawaiian Islands were taken by pole-and-line and trolling gear, while 5,1,1 Fishing gear frigate mackerel from Japan were recorded as being taker by pole-and-line fishing. The A. maru is caught in pound nets, set nets, drift netsand by rod and line In TaiwanD large numbers of set nets are (Kishinouye, 1923). Serventy (1941) states: placed everywhere along the eastern coast to "Shoals of hundreds of individuals appear capture the s&dagatsuwo (Auxis sp.) during the summer months at coastal fishing (Nakamura, 1937). resorts in southwestern Australia and in the region of Sydney, and numbers may be cap- Okachi (1958) states that in the Japan Sea tured by beach seining.It is not usually and East China Sea regions, the main iti of taken bV ordinary trolling gear like the other gear used in the frigate mackerel fishe is tunas.1' trap nets, which produce most of the catch in both of these regions. Consequently, the Tester (1952), an the other hand, in trying catches are highest in the Prefectures of to establish tuna and other pelagic fishes in Niigata, Toyama, Ishikawa, Fukui, Kyoto, and ponds and tanks, reportedly took most of his Yamaguchi, where trap net fishing is active. fish by trolling. Fishing took piace in an area In the East China Sea region, Nagasaki and off Mokumañu (Bird Island), near Kaneohe Bay, Kagoshima Prefectures produce the bulk of the Oabu, Hawaii. He used a variety of relatively catch, with only small quantities being taken small lures, suc1 as greenish or brownish elsewhere. pliable-rubber imitation squid, gray or red metal-headed imttation squid with white rubber The trap net or fixed net fishing as prac- arms, and red or white metal-headed jigs. ticed in Japan consists of a leading net that may Between the period from January 18 to be as deep as 100 meters and stretch out as far October 18, 1951, 381 fish were taken, of as 4,000 meters offshore (Anonymous, 1957). which 280 were tuna (Thunnidae). Twenty- The cube-shaped bag or pound net is set near two of the tunas aken were frigate mackerel the coast and i-nay be 5 meters deep. Fisher- (A. thazard) rangIng L.'om i to 2-1/2 pounds men tending these trap nets wait for migration (32 to 37 crin .nngth).Teßter stated that of a school of fish that are moving c1oe to Lrigate mackerel, tunny, and yellowfin were shore. Nets with larger meshes are used caught sradical1y frai-n May orJune to mainly for the capture of large species of fish September or October. such as mackerel, yellowtail, and tuna, while nets with smaller meshes are usedfor the Warfel (1952) says that of the twospecies of capture of small species like the sardine. frigate mackerels known inPhilippine waters, namely A. thazard and A.apeinosoma the These fined nets are generally drawn up formereïnates iiÇthe commercial catch. twice a day, once in the morning and once in In addition to purse seines,the frigate mack- the evening. However, the time varies with erels are also taken by fish corrals. the quantity of fish captured in the net. The pole-and-lineslivebait method of 5.1.2 Fishing boats fishing is also used in takingfrigate mackerels. One incident of frigate mackerelsbeing taken Although much of the commercial fishing by this method in Hawaiian waterswas dis - for the Auxis is done with trap or set ne,ts, cussed in section 2.1,

2 70 5:2 Flb/S51 Frigate Mackerel there are occasional catches made by pole- 5.3 Fishing seasons and-line fishing.In Japan and Hawaii, the pole-and-line, livebait method of fishing is 5.3.1 General pattern of fishingseason primarily for skipjack. Seeection 3.5.1, Migration and local The present day Japanese skipjack movements boats are either of wood or steel construc- tion.Wooden vessels range from 60 to 5.3.2 Duration of fishing season 135 tons and average about 80 to 90tons. Steel vessels are generally much larger, See section 3.5.1, Migration and local ranging from about 100 tons to about 300 moveme nts tons with the majority in the 120-180 ton class (Imamura, 1949). 5.3.3 Dates of beginning, peak, and end of season The Hawaiian skipjack boats are much smaller than the Japanese vessels, and Shapiro (1948) states that A. lira appears although these boats evolved from the in abundance in the Ryukyu Islands during July. Japanese sampan-type tuna boats, modifi- This is somewhat later than the time that the cations in design have made the Hawaiian migrating schools of skipjack pass through the boat of today a distinct type of vessel adapted Ryukyu waters on their annual movement into to local needs and conditions.The boat Size Japanese waters, ranges from 29 to 92 feet in overall length with the majority about 70 to 88 feet in In the Taiwan trap-net fishery, large length (June 1951) numbers of set nets are placed along the coast to capture the very dense schools of Skipjack boats are equipped to carry s6dagatsuwo (Auxis sp.) which migrate into the live bait and scout the offshore waters in coastal water from April to the first part of search of fish schools, July (Nakamura, 1937). 5.2 Fishing areas 5.4 Fishing operations and results 5.2.1 General geographic distribution 5.4.2 Selectivity In a discussion of the principal marine The set-net fishery for Auxis as it is fisheries of the Philippine Islands, Manacop carried on in Taiwan is not very seltctive (1952) listed the fishing areas for the frigate according to Nakamura (1937). He states that mackerel (A. thazard) in Philippine waters. besides the Auxis, other miscellaneous species These areas are the northern and north- including cybiide and spearfishes are caught in western Zambales coast, Manila Bay, these set nets. Batangas and Balayan Bays, Rahay Gull and Dunas Pass, San Miguel Bay, southern 5.4,3 Catches Zamboanga, and the Sulu Archipelago. In Hawaii,he commercial importance of See also sections 3,5.1, Migration and the Zrigate mackerel is very slight.Gosline local movements and 5.4. 3, Catches, ad :ock (1960)'eport thtIc £Lgae mack.- ere t.l;JL1 cy Licide11y tu Liuhing 5.2.2 Geographical ranges (latitudes, opera1one. Occaona1 catcheri or this species distances from coast, etc.) ar made rihiic fishing schooJs of .uthyunus yaico. See sections 3.5.1 and 5.1. F'igexe mackerel taken in Australia are 5.2.3 Depth ranges also of very little commercial value (Serventy, 1 941) .JJthough it has been reported that Kishinouye (1923) gave the range of the 1age scIcol s of this species appear during vertical distribution of A. lira as being from the sumnr months in southwest erù the surface to about 45 meters. Australia, specimens that appear on the

271 FIb/51 Frigate Mackerel 5:3 markets are usually disposed of for bait. tween 1952 and 1956, the largest catch of frig- Roughley (1951) added that in Australia the ate mackerel was in the year 1954, when economic feasibility of commerci al approximately 570, 000 kan (1 kan8.27 exploitationf this species has yet to be pounds) was landed.It can be seen from the demonstrated table that the middle and south Pacific regions had the highest production of frigate mackerels. Japan lands far more f ri gate mackerel than any other country, and is in fact the 5. 6 Fi ah farming, transplanting, and only country which fishes the species in other intervention commercial quantities. Between the years 1952 to 1959, the average catch of this The only information available under the species amounted to 21 800 metric tons heading of transplanting of frigate mackerel (1 metric ton1.102 short tons) with a may be found in the work by Tester (1952) low of l56 metric tons in 1953 and a high During 1951, Tester attempted to catch various of 25,9 metric tons in 1956 (FAO, 1954.-55, species of tuna, transport them in a ship s 1959) livewell, and estabi ish them in ponds and tanks at the Coconut Island branch of the Okachi (1958) studied the distribution Hawaii Marine Laboratory. The purpose was of the Auxis in the Japan Sea by examining to provide specimens for a study of the the catch statistics.In his report, he reaction of tuna to various types of stimuli. states that al most all of the Auxis in the Japan Sea are marus6da (A. maru) while Tester caught 22 frigate mackerel be- hirasda (A. hira) are taken only rarely. tween January18 and October 18, 1951. 0f Looki ng at the catch by regi ons in Japan, these, six were successfully transported to he found that the Pacific southern region shore. He noted that their behavior on deck has more than 60 percent and the Pacific and in the livewell of the vessel was very central regi on has about 20 percent, while similar to that of the skipjack in that when the Japan Sea and East China Sea regi ons landed, the fish gave convulsive shudders. He produce only about 10.-15 percent of the stated,however, thatthe frigate mackerel did catch.Furthermore, he found that the not bleed profusely at the gills like the skipjack. catches from the Japan Sea northern region He was more successful in transporting frigate and the East China Sea region are about mackerel back to the ponds as compared with equal, while the catch of the Japan Sea ski pjack, and thi s was attributed to the western region, whi ch lies between these greater swimming room in the 1 ivewell t, is small er than either of them. resulting from the frigate mackerel' s smaller size.Those that survived the trip back to The annual catch of frigate mackerel s in the ponds were, however, frequently bruised Japan is shown by regi ons for the years from and battered. 1952 to 1956 in Table V. (Okachi, 1958: table 6) .Okachi states that for the Japan Sea be- Table V Yearly catch of frigate mackerel by region

Region Year 1954 Grand total 6,418 5,494 6, 913

Hokkaido li 9 10 10 North Pacific 153 199 92 454 Middle Pacific 1, 523 784 945 2,021 South Pacific 4, 335 2, 537 3, 574 3, 757 East China Sea 1 47 256 287 272 Wèst Japan Sea 108 1 88 407 222 North Japan Sea 119 164 1 62 168

272 5:4 FIb/S51 Frigate Mackerel During May and June of 1951, Tester intro- duced three frigate mackerel, one little tunny, and six yellowfin into one of the two ponds at Coconut Island,The frigate mackerel dashed wildly across and around the pond. One battered itself on the coral sides of the pond and died within a few minutes, The remaining two swam rapidly for a short time, then dis- appeared in deep waters of the pond and were not seen again. He presumed that they died within a short time.

273