Food of Lancetfish, Alepisaums Ferox Lowe, Fished by Gill-Net in Suruga Bay, Japan*

J, Fac. Mar. Sci. Technol., Tokai Univ., No. 10, pp. 137—US (1977)

Food of Lancetfish, Alepisaums ferox L o w e, Fished by Gill-Net in Suruga Bay, Japan*

Tadashi K ubota

Abstract

Seventy-lhrt-e specimens a( Inncjetfislt, Alirfrisaiiru^ ferox Lowe, were collected by gill- ntt in the surroundinfi waters of Milio Key during the months from December to July in 196S-197.J. Slomach contents of these spcdmcni were analyzed. The reiuJts were compa red with the stomach analysis of lancetfish stranded ashore (Kubota & Uyeiio, 1970). 1. Tlie fond in the slomaclis is compohcd of six groups, i. e., polychaetes, crustaceans, mollusks, protochordates, fishes and non-living substances. Coclenteraies and echino- derms which were rcfiorted from the stomachs of [he Itinceifish stranded ashore are not found in the giU-nettet! lancetfish,

2. The dominant species of fishes m the stomachs arc Trkkiurus Upluru^, Harettgulu zunasi, Engmulij; japomca, Konvsirus jiiinclaUa iitid Kovodon modcstas in the order of dominoney. Decapodjn crustaceans, mainly micronektonic shrimp, Sergtstc^ liiccns, which were abundant in the stomachs of stranded ianccirish, are scarce in the stomachs of sill-netled lancetfish. Molluscan decapod, Todarades pacijicas, occurs in larger num ber than in stranded lancetfish. 3. In general, dominatit fishes found in the stomnchs (if gill-neited lancetfish belonR to the orders of Clupeiformes, Pcrciforme.i and Tetraodonlif irmes inhEhitinf; the upper-mid layer in the sea. On the other (land, dominant fishes from stranded lancetfisfi belong to the orders Berycitormes, Perciformcs and Lophiiformes inhabiting the mid-deeper layer- 4. Common specics of fishes found in both stranded and gill-netted lancetfish in Suruga Bay occupy 30% of totni number of species in all stomachs. 5. Plastic products from chemical synthetic resin were frequently found in the stomachs of lancetfish : of stomachs in stranded specimens, and 61.6?i in giil-netted specimens.

Introduction

A great number of lancetfish, Alepisaitrus ferox, are taken by gill-net, set-net, tow-net. and other gear in Suruga Bay. The samples can be also collected on the beach of Miho Key, the innermost portion of the bay where the fish are stranded. The stomach contents of lancetfish stranded on the beach of Miho Key have been studied by the author since 1964, and the feeding of this fish seems to be non-selective. There will be a competition of food among lancetfish, sharks, dolphins, and other large fishes in Suruga Bay. The

•Contrilwtior A No. 115 from the Foculty of Marine Science and Technology, Tokai University. Accepted November 30, 1976

TabJe 1 Number of lancetfish, Akpisaurus feroj:, examined in this study.

Month Dcc. Jan. Feb. Mar. Apr. May. Jun. Jul. Totol Year

1069 1 1970 2* t) 15 1971 12 17 33 1972 1 4 20 1973 'I 4

Total 19 26 73

* ; The stomuL-h of one of two lani-etfish was empty.

The number of specimens of lancetfish obtained is 73 in total (Table 1). The stomachs were removed after lancetfish specimens were fixed with 10—-20% formalin solution. The contents of the stomachs were usually in good condition. Among the con tents fish specimens were counted in number and body length (B, L.j or total length (T. L.) was mea.surcd. In ccphalopods the dorsal mantle length (D. M .L j was muasured. Jaws of cephalopods, pieces of woods, and plastic objects were counted in regardless of si^e, but were omitted from percentage calculation for each group of food in Table 2. To facilitate comparison, tht^ results were tabulated in the similar way to the previous report (Kubota & Uyeno, 1970).

Results of Observations

Food organisms in the stomachs w'ere classified into six groups, i.e. polychaetes, crusta ceans, mollnsks, protochordates, fishes, and non-living substances. The total number of organisms in the stomachs amounted to 1,048 in 72 stomachs. Of 73 stomachs only one was empty. Fishes constituted 35. 0% in number of total animals in the stomachs. The percentage representation of five dominant fishes was Trichiurus lepturus 14. 0% of total fishes, Harc- ngula zuttasi 13. 2^^, Eiigraulis japotiica 12. 9%, Kofw,urus pimctatus 9.9% and Navodon modestus 9 ,9%. Protochordates constituted 29.6% of total individuals of al! organisms eaten. Crustaceans consituted 22. 4% of total animals. An amphipod, Phronima sedcntaria, was eaten by 25 lancetfish throughout the period of the study. Fourteen individuals of Sergcstes luccns, 8. 0% of total crustaceans, occurred in the stomachs. Mollusks (heteropods, pteropods and cephalopods) occupied 12.6% of total animals In the stomachs. Sixty-five individuals of common squid, Todarodes pacificus, were, present in the stomachs (Table 2). Fishes occurring in the stomachs of the lancetfish belongs to the orders of Clupeiformes (36.3^ of total fishes), Perciformes (19.9^ ) and Tetraodontiformes (14.7% ) (Table 3). In addition to food organisms, plastic products of chemical synthetic resin, such as polye thylene and vinyle were frequently found in the stomachs, 2. 2 pieces per specimen on the average. Fourty-five of 73 specimens of lancetfish had taken peices of polyethylene or vinyle. The feeding ratio was 61. 6^1^ (Table 4). Table 2 Stoinach contents of lancelfish taken by gill-net in Suruga B»y.

No, of individuals Month D J F MAM J J Siie in mm Tola! no.

No, of specimens of A. ferox 3 19 26 6 7 4 1 7 73

Mollusks 9a PterotTachta coronata 1 1 '■,5 CavoUnia gibbosa 1 1 C. unicmata 1 1 Scpiolijia nipponensis 1 DML. 25 1 Loligo juponica 1 1 1 n 45- 100 3 L- sp. 1 // 32 ] Onytia japonica 1 /y 52 i 0. sp. 1 3 // 5 21 4 Histioteuthis inerTnis 1 f! r>4 1 H. sp. I (> IS 1 Tadarodes pacificas 1 28 29 2 3 1 1 // 12-24S 6r, Ckiraiesithis imperatar o 2 30 S4 4 Gottalus oayx 1 ff 17-25 4 Amt

N«. of individuals Month D J F MAM J J Size in mm Total no.

No. of specimens of A. /srox 3 19 26 6 7 4 1 7 73

Engraulis japonica 1 9 9 1 1 2 12 BL 40-1^7 35 Konosirui punclaius 6 20 1 // 115*234 27 Lestidium prolijmm 3 10 4 // 95-150 17 Lfpioilitmias multijilis 1 1 // 94-117 2 Myctaphum orientale 1 1 // 37 2 Dipltiphos orientalis 1 // 73 1 AUpisaurtti ftrax I // 980 1 Jiarpotion micrachir 1 2 // « 2 -6 a 0 3 Naloscopclns japnnicus 1 // 120 1 Floloms angttiltaris 1 // 210 1 Nfmichlhys scolvpdccui: 1 TL 200 1 Kchelus uroptcrus 1 ff 333 1 Xyrias rcvalsus I // :-20 1 Ccmger eel 1 ft 75 1

Macrorhtimpkasus jtiponicus 1 BL 57 1 Fistsilariii pciimha 1 1 // 287-430 2 Syngnathu^ schlcgeli 1 1 // 7 5 -U : 2 CephyrDheryx japvnicus 1 1 n 3G-71 2 Ztus jiipunicai 1 // 30 1 ZcJiopsis ncbulo^a 2 1 8 // 45-114 11 Trickiuras leptunii 2 J2 4 iS 2 5 TL 130-663 38 LdognaShus rivulatus 1 BL 42 1 L. nuchalis 1 2 1 /! 40-83 4 7'rachurus japanicus 1 // 31 1 Scomber japonicus 1 H S9 1 FrnmeMchlhys pramcthcus 1 1 ff 94-224 2 Chacturicfuhys hcxanema 1 tt 123 1 Acanlkogabius flavimanus I // 49 1 CalUonyrnus richardioni I H 117 1 Scombrop! hoops 1 II 178 1 Ocycrius japonieus 1 // 19 1 Therapon jarbua 1 n 5S 1 Apagon lineatus 1 n 37 1

Chelidanichthys kumu 1 N 160 1 Bregmaceros japonieus 1 n 42 1 Physicalm japotticas 1 // 159 1 Pseudorhombus cinMmoneas 1 n 150 1 Heterosomata 1 1 // 15-21 2 Navodon modtslus 5 B 2 5 1 6 // 17-195 27 Lagocepkalus lunaris 3 1 1 // 59-113 5 CajUhigasUr rivulatus 1 // 70 I Sphoeroidcs vermUularii 1 n 195 1 142 Tadashi K ubota

(Continued—2)

No. of individuals Month D J F M A M J J Size in mm Total no.

No. of specimens of A. Jerox 3 19 26 6 7 4 1 7 73

S. porphyreus 1 BL 315 1 Triacanthus brfvirostris 1 // 102 1 Liosaccus cutaneous 1 1 27-200 2 Slephanolepis cirrhifer 1 V 138 1 Puffer 1 // 32 1 Lophius litulon 1 1 6 1 " 32-44 9 Unidentified fish 1 5 ■5 1 2 17-2H0 14 P ans of fishes 4 1 4 9 1 19 Feather of birds 1 1 2 Beaks of cephalopods 1 1 3 1 6 Fragmetits of gladius 1 1 2 Pieties of polyethylene Si vinyle 6 38 49 22 19 15 3 5 157 Bottle o£ polyethylene 1 1 Rubber 1 1 Pieces of straws & leaves 1 4 1 2 3 8 7 26 Pieces of woods 4 7 10 1 1 5 1 29 Pieces of grass stems 1 3 3 1 2 10 Fragments of kelps 2 2 4 Fragments of orange 1 3 7 11 Fragments of vegetables 2 2 4 Others 1 3 2 6

Abbreviaticns ; BL, body length ; DML, dorsal mantle length ; TL, total length.

Table 3 The number of fish occurring in siotnachs of Alepisaurus in three sea areas,

_ Area N. w. Pacific gill-net stranded S. e. Pacific N. Atlsntic Fishes catch ashore

Clupeiformes 98(36. 0) 21C 8.7) 66(35. 5) 80(29. 9) Myctophi formes Aleptsaurus young —— 25(13. 4) 42(15, 2) Alepisaurits adult IC 0.4) --—— Other alepisauroids 17( 6. 3) 6( 2. 5) 49(26. 3) 70(26. 1) Myctophids 9( 3. 3) 12( 5. 0) 2( 1. 1) K 0. 4) Siiuriformes K 0. 4) IC 0.4) —— Miripinnatiformes ~ — 3( 1.6) — Anguilliformes 4( 1.5) K 0.4) 2( 1. 1) 5 ( 1. 9) Beioniformes - 1( 0. 4) —— Food of Lancetfish Fished by Gill-Net 143

(Continued)

Area N. w. Pacific gill-net stranded S. e. Pacific N. Atlantic Fishes .. catch ashore

Syngnathiformes 5( 1. 8) 3( 1.2) — 1( 0. 4) Bcryciformes 2( 0, 7) 97(40. 1) 6( 3. 2) 4( 1.5) Lampridiformes — 4( 1.7) 2( 1. 1) K 0.4)

Zeiformes I2( 4, 4) 4( 1.7) — — Perciformcp 54(19. 9) 44(18. 2) 23(12.4) 50(18. 7) Cottiformes K 0.4) 5( 2. 1) — 2( 0. 7) Tetraodontlformes 40(14. 7) 8( 3. 3) — K 0. 4) Pleuronectiformes 3( 1.1) — K 0. 4) Gfldiformes 2( 0. 7) — 8( 4.3) 6( 2,2) Lophiiformes fl( 3. 3) 26(10. 7) — 4( 1.5) Unidentified fish 14( 5. 1) 9( 3, 7) ——

Total 272 242 166 268

Numerals in psrentheses show ihe perccnuge in total number of all orders.

Table 4 Number of pieces of polyethylene or vinyle products occurring in the stomachs of lancetfish taken by Eill-net.

No. of Total no. Average no. No. of lancetfish with of pieces of of pieces of Year lancetfish pieces of polye polyethylene polyethylene or thylene or vinyle or vinyle vinlye per fish.

1 9 G 9 1 1 1 1. 0 1 9 7 0 15 7 17 1. 1 1 9 7 1 33 22 69 2. 1 1 9 7 2 20 12 62 3. 1 1 9 7 3 4 3 e 2.0

Total 73 45 157 2. 2

Discussion

Fig. 2 shows the comparison of food components between stranded (Kubota & Uyeno, 1970) and gill-netted lancetfish (present study). The group occurring most abundantly in the stomachs of lancetfish taken by gill-net is fish (35. Q% of total number), followed by protochordates (29.6%) and crustaceans (22.4%^. On the other hand, the major groups in the food from stranded lancetfish are crustaceans (46.0%), fishes (25.6%), and proto chordates (15. 3^^) (Kubota & Uyeno. 1970). The localties from where the lancetfish were obtained either on the shore or by gill-net are practically in the same area (Fig. 1). Not withstanding, there is a difference in food components in the stomachs between these two groups. When lancetfish seek prey near the bottom of mid-deeper layer, they are often stranded on shore. The gill-netted lancetfish apparently swam at the depth of mid-upper op«n sea. This will be merely due to the difference in fish fauna between Suruga Bay and open sea of Pacific and Atlantic. In the stomachs of gill-netted lancetfish as well as stranded lancetfish (Kubota & Uyeno, 1970), no small specimen of lancetfish is found, though a stomach from gill-netted lancet fish contained one adult lancetfish (Table 3). Absence of small specimens of lancetfish in Suruga Bay suggests that the spawning takes place somewhere outside of the bay. Occurrence of large number of plastic products indicates increasing pollution of water due to city wastes in Suruga Bay (Fig. 3),

References

FouKMANom, p. C196S) ! Contenus stomaoauK i'AUpisaurtts (Polssotis) dans le Sud-Ouest Pacifiiiue. Cah, O. R, S. T, O. M„ scr. O « a n 0Br„ 7 (^), 51-60. Haedkich, R. L. (1964) : Food habits and younf; stages of Norih Atlantic AUpisaurus (Pisces, Iniomi). Breviorn, (201;, 1-15. ------and J. G. Nielsen f I%6) : Fishes eaten by AUpisaarus ( Pisces, Iniomi) in the southeastern Pacific Ocean. Deep-Sea Res., i:i (13), D09-yi9. Kubota, T. (1971) : Food of nnglerfish, Lophius lilulon, obtained from stomnchs of lancetfish, Alepiiaurus fi'rox, in Suruga Boy. Bull. Plankton Soc. Japan, 18 (1), 28-31. (In Japanese). ------(1*373) : Four links of food chain from the lanoetfisii, Alepisauras fcrox, to zooplankton in Suruga Buy, Japan. J. Fac. Mar. Sci. Ttchnol., Tokai Univ., (7), 231-2^3. ------and T. Mori (1975) : Morphology of '* barrel ” of Phronima eaten by lancetfish, Alepisaurn^

fcrox L owe, in Suruga Bay, Japan. Ann. Rep. Mar. Sci. Mus., Tokai Univ., (2/3), 61-65. (In Japanese;, —^— and T. Uycno (1970) : Food habits of lancetfish Akpisaarus ferox (order My:tophiformes) in Suruga Bay, Japan. Japan. J. k-hthyol., 17 (1), 22-28.

OKtjTANi, T. and T. K ubota. (1976) : Cephalopods eaten by lancetfish, Alcpisaurui ferox L ow e, in Suruga

Bay, Japan. Bull. Tokai Reg. Fish. Rea. Lab., (S4), 1-9.

R ancurel, p. (1970; : Les contenus stomataux A'Altpis.aunis ferox dans les Sud-Ouest Paoifique (Cephalo- podes). Cah. O. R, S. T. O, M., ser. Oceanogr., 8 (4), 3-87.

ReniBrk r After the manuscript of this paper was submitted, Fujita and Hattori’s paper (1976, Japan. J. Ichlhyol. Vol. 23, No. 3, pp. 133— 142) dealing with stomach analysis of lancetfish from the eastern Indian Ocean and the Coral Sea, southwestern Pacific Ocean,was published. In their paper, it was suggested that stomach contents also reflected the composition of the fauna in the sea, similarly to the present studies. x m i i IE

^ &

Alepisattrus ferox OF?LT, mW. (Kubota & Uyeno, 1970) OfJ_t

m m , ^MW jH fc - f tf . 1, (order) SlJtrii, ^v>B, ^ B f^JS.-t ^<. (Kubota & Uyeno, 1970) -CSl, ff'( T v j S b!S.hhi>m ^i3'^^hhfz.

L ; i ' 30^ (4t^i5fftms':;f;‘ff¥) tc*.-