Bull. Natn. Sci. Mus., Tokyo, Ser. A, 31(4), pp. 151–156, December 22, 2005 Record of a Whale Louse, Cyamus scammoni Dall (Crustacea: Amphipoda: Cyamidae), from the Gray Whale Strayed into Tokyo Bay, the Pacific Coast of Japan Masatsune Takeda1and Michiru Ogino2 1Department of Zoology, National Science Museum, Tokyo, 3–23–1 Hyakunincho, Shinjuku-ku, Tokyo, 169–0073 Japan e-mail: [email protected] 2Marine Mammal Center, Japan, 30 Yokoderamachi, Shinjuku-ku, Tokyo, 162–0831 Japan e-mail: [email protected] Abstract A whale louse species referable to Cyamus(Apocyamus) scammoniDall, 1872, a crus- tacean ectoparasite of the gray whale, Eschrichtius robustus(Lilljeborg), was found in great num- bers on the body surface of a young individual that strayed into Tokyo Bay in mid-April, 2005, and was found dead in a fixed net on 11 May, 2005. In the northwestern Pacific populations of E. ro- bustus, the whale louse has been known only from Korean and southern Kamtchakan waters, and therefore the present record is the first from Japanese waters. The known species of the whale lice from Japanese waters are listed, with the host whale species. Key words: Whale louse, Cyamus, Apocyamus, Cyamusscammoni, gray whale, Eschrichtius ro- bustus, Tokyo Bay, northwestern Pacific. In mid-April, 2005, a young gray whale of the National Research Institute of Far Seas strayed into Tokyo Bay and had a high popularity Fisheries, the Institute of Cetacean Research, and among the people in the metropolitan area with the National Science Museum, Tokyo. The whale enthusiastic reports by the mass communications. was infested with numerous whale lice of vari- This whale was reported to be the gray whale, able sizes aggregating as several big patches. A Eschrichtius robustus (Lilljeborg) that is distrib- mass of the specimens collected from the inferior uted in the northern North Pacific. The north- surface of left lobe of the flukes were kept by M. western populations of this species are at present Ogino, one of the authors, and then, about half of in an endangered state with the individuals less them were transferred to the National Science than 100. Some attempts to expel the whale from Museum, Tokyo, for the taxonomic study. The re- Tokyo Bay to the open sea came to nothing, and sults of the examination will be presented herein. thus some researchers including one (M.O.) of the authors were afraid that the whale would Class CRUSTACEA Order AMPHIPODA starve to death because of lack of plankton to sustain nature. The whale went missing for a Family Cyamidae time, but later, on 11 May, 2005, was found dead Genus CyamusLatreille, 1796 in the fixed net laid 1 km off Tomiyama-machi, Subgenus ApocyamusMargolis, McDonald Chiba Prefecture. It is quite unfortunate that the et Bousfield, 2000 whale was drowned in the fixed net probably on Cyamus(Apocyamus) scammoniDall, 1872 the way to the open sea. [New Japanese name: Koku-kujirajirami] On examination of the carcass, the whale was (Figs. 1, 2) young, with 7.9m in length, being definitely identified with E. robustus by the research group Cyamus scammoni Dall, 1872: 281.—Lütken, 1887: 152 Masatsune Takeda and Michiru Ogino 318.—Margolis, 1954: 319.—Margolis, 1955: slightly narrower, with pair of weak adhesion 129.—Hurley & Mohr, 1957: 353.—Leung, 1965: spines each on the peraeon segments 6 and 7. In 135.—Leung, 1967: 282 (in key), 287 (in list), fig. 3a. the female the coxal gills are distinctly coiled as Cyamus (Apocyamus) scammoni, Margolis et al., 2000: in the male and different from those of the other 68 (in key), 90, figs. 13, 14. species, without accessory gills contrary to the Material examined. A total of 1,290 speci- turgid unequally paired gills in male. mens ranging from minute juveniles (0.5–1.0mm In the mature specimens the outline of the in length from the first to last segment) to mature body is typically ovate, but it is apparent that the individuals (about 10mm on average, the juvenile and young specimens vary in their body biggest, 16.4mm)—830 exs (NSMT-Cr 16473), shape, gradually widening with the advanced de- 300 exs (NSMT-Cr 16474), 140 exs (NSMT-Cr velopmental stages; in the minute specimens 16475), 20 exs (NSMT-Cr 16476)—From infe- each segment is rather trapezoid and separated rior surface of left fluke of Eschrichtius robustus from each other; in the juvenile smaller than ca. (Lilljeborg), Tomiyamamachi, Chiba Prefecture, 1.5mm in body length, the gills are elliptic just Tokyo Bay, 11 May, 2005. like those of typical caprellids, and in the speci- Remarks. According to Margolis et al. mens slightly larger than this size, the gills be- (2000), this species is referred to the subgenus come thick and club-shaped. Afterward, the gills Apocyamus established by them based on the elongate and become spiral. The body color be- combination of such characters as the outer plate comes darker from translucent white in the juve- of the maxilla 1 having 7 apical spines, with its niles to purplish dark brown in the adults. In the inner distal margin strongly setose, the epistome photographs reproduced herein (Fig. 1), the gre- of the upper lip weakly or not developed apically, garious masses of the adults and the juveniles the head short, little (or not) longer than basal and young on the inferior surface of the flukes width, the propodi and dactyli of the peraeopods are distinguished by dark and flesh tint, respec- 5–7 relatively short and weak, and the propodus tively. of the gnathopod 2 short and deep, with conical The strongly adaptive life cycle of C. scam- palmar and hinge teeth on the palmar margin. moni was elaborately studied and described by This species is the largest and quite unique in Leung (1976), together with two associated the Cyamidae due to having the very broad, ovate species, C. ceti (Linnaeus) and C. kessleri body, especially in male, and the spirally coiled Brandt. coxal gills. The peraeon segments 3 and 4 are the The specimens at hand were not compared di- broadest, with the weakly convex lateral margins, rectly with the specimens from the northeastern being followed by the succeeding segments Pacific, but so far as we compared them with the weakly narrowing posteriorly. The head is short, photographs and consulted the literature for their but broad posteriorly at the fused peraeon seg- definite identity, any differences between the two ment 1. The eyes are small, rounded and weakly populations were not found for the intraspecific pigmented. The gnathopod 1 is 6-segmented and differentiation except for the remarkable varia- not so heavy as usual, with the talon-like dacty- tion according to developmental stages. Andrews lus. The gnathopod 2 is stout and strong, and its (1914: 260) mentioned that the specimens from hinge tooth is acute and larger than the proximal Korea were certainly identifiable with C. scam- palmar tooth, with the gently curved talon-like monifrom California. dactylus. The peraeopods 5–7 are not very robust Distribution. This species is specific to gray as a whole, and their propodi are relatively short whale, Eschrichtius robustus in the North Pacific and subovate, with the short and curved dactyli. from Korea (Andrews, 1914) and Japan (present The female is not much different from the study) through the vicinity of the Kamchatka male in the general body form, the body being (Zenkovitch, 1934 and 1937, without definite Whale Louse on Gray Whale from Tokyo Bay 153 Fig. 1. A, a young gray whale, under dissection, showing inferior surface of the fluke; B, a mass of whale lice on left lobe of the fluke; C, a mass of whale lice around eye. 154 Masatsune Takeda and Michiru Ogino Fig. 2. Whale lice, CyamusscammoniDall, parasitic on the gray whale. A, a mass in close-up; B, a young indi- vidual in dorsal view; C, D, a medium-sized individual in dorsal (C) and ventral (D) views. (Scales in mm) identification to the species), the Bering Sea fifth of the family Cyamidae. Ishii (1915) exam- (Margolis et al., 2000), Alaska (Hurley & Mohr, ined many specimens obtained from the Baird’s 1957; Leung, 1965), and British Columbia (Mar- beaked whale, Berardius bairdiiStejneger caught golis, 1954, 1955; Margolis et al., 2000) to Cali- in the sea off Tateyama, Awa ((cid:1)Chiba Prefec- fornia (Dall, 1872; Leung, 1965, 1976; Margolis ture), and mentioned that they are close to Para- et al., 2000). cyamus boopis(Lütken) and remarkably different from Cyamus ceti(Linnaeus). Paracyamus boop- is is currently known as Cyamus (Paracyamus) Whale lice (Crustacea, Amphipoda, boopis after Margolis et al. (2000). Later, Iwasa Cyamidae) from Japanese waters (1934) recorded C. ovalis Roussell de Vauzème In Japanese waters, the present species is the and C. erraticus Roussell de Vauzème obtained Whale Louse on Gray Whale from Tokyo Bay 155 from the North Pacific right whale, Eubalaena beaked whale [Tsuchi-kujira]; Megaptera no- japonica Lacépède (recorded as Balaena vaeangliae, Humpback whale [Zatou-kujira] glacialis Bonnaterre) captured in the North Pa- Cyamus (Apocyamus) scammoni Dall 1872 cific, both of which are referred to the subgenus [Koku-kujirajirami]—Eschrichtius robustus, Cyamuss.s. by Margolis et al.(2000). Gray whale [Koku-kujira] Hiro (1938) described a new species, Cyamus Isocyamus globicipitis (Lütken, 1873)—Globi- elongatus, based on the specimens obtained from cephala macrorhynchus, Short-finned pilot the humpback whale, Megaptera novaeangliae whale [Kobire-gondou] (Borowski) from Japan. It was, however, reduced Cyamus (Paracyamus) balaenopterae Barnard, to a synonym of C. (P.) boopis by Margolis 1931—Balaenoptera acutorostrata Lacépède (1955) who definitely said that C. elongatus rep- [Minku-kujira] resents the juvenile stages of C. boopis. Hiro (1938) also mentioned, incidentally, that he ex- Acknowledgments amined the whale lice attached to the short- finned pilot whale, Globicephala macrorhynchius The authors wish to thank Dr. Hidehiro Kato Gray caught off Taiji, the Kumano-Nada Sea, and of the National Research Institute of Far Seas that the species identified with C. globicipitis Fisheries, Fisheries Research Agency, and Dr. Lütken has never been recorded from Japanese Hajime Ishikawa of the Institute of Cetacean Re- waters. Cyamus globicipitis was listed in the search for their support and help in collecting the synonymy of Isocyamus delphinii (Guérin- whale lice specimens from the gray whale Méneville, 1836) by Leung (1967), but was re- strayed into Tokyo Bay. Dr. Toshiaki Kuramochi tained in the genus Isocyamus as distinct from I. kindly provided the authors with the information delphiniiby Margolis et al.(2000). and literature of whale lice from the North Pacif- While studying the parasite fauna of the minke ic. whale, Balaenoptera acutorostrata Lacépède from the northwestern Pacific far off Hokkaido References (40–52°N, 157–170°E, excluding the Russian and US 200 miles EEZ), Kuramochi et al.(1996) Andrews, R. C., 1914. Monographs of the Pacific Cetacea. I.—The California gray whale (Rhachi- and Araki et al. (1997) recorded only the occur- anectes glaucus Cope). Mem. Amer. Mus. Nat. Hist., rence of Cyamus balaenopterae Barnard as one (n.s.), 1: 229-287, pls. 19–27. of the ectoparasites. Although the sea in question Araki, J., T. Kuramochi, M. Machida, K. Nagasawa & A. is administratively outside the territory of Japan- Uchida, 1997. A note on the parasite fauna of the west- ese waters, the addition to the carcinological ern North Pacific minke whale (Balaenoptera acutoros- trata). Rep. Int. Whal. Commn., (47): 565–567. fauna may be reasonable. Barnard, K. H., 1931. Diagnoses of new genera and The following is a list of the whale lice from species of amphipod Crustacea collected during the Japanese waters in chronological order, with the ‘Discovery’ investigations, 1925–1927. Ann. Mag. Nat. host whale species. Hist., (10), 7: 425–430. Cyamus (Cyamus) ovalis Roussell de Vauzème Dall, W. H., 1872. Descriptions of three new species of 1834 [Maru-kujirajirami]—Eubalaena japon- crustacean from Cetacea. Proc. Calif. Acad. Sci., 4: 281–283. ica, North Pacific right whale [Semi-kujira] Hiro, F., 1938. Cyamus elongatusn. sp., a new whale-lice Cyamus (Cyamus) erraticus Roussell de Vau- from Japan. Annot. Zool. Japon., 17: 71–77. zème 1834 [Hime-kujirajirami]—Eubalaena Hurley, D. E. & J. L. Mohr, 1957. On whale-lice (Am- japonica, North Pacific right whale [Semi- phipoda: Cyamidae) from the California gray whale, kujira] Eschrichtius glaucus. J. Parasitol., 43: 352–357. Ishii, H., 1915. [A cyamid obtained in the Province Awa.], Cyamus(Paracyamus) boopisLütken, 1870 [Ho- Dobutsugaku Zasshi ((cid:1)Zool. Mag.), Tokyo, 27: 157– so-kujirajirami]—Berardius bairdii, Baird’s 159. (In Japanese.) 156 Masatsune Takeda and Michiru Ogino Iwasa, M., 1934. Two species of whale-lice (Amphipoda: Skr., (5), 10:229–284 , pls. 1–4. (In Danish.) Cyamidae) parasitic on a right-whale. J. Fac. Sci. Lütken, C. F., 1887. Tillaeg til “Bidrag til Kundskab om Hokkaido Imp. Univ., (6), 3: 33–39, pls. 4–7. Arterne af Slaegten Cyamus Latr. eller Havallusene”. Kuramochi, T., M. Machida, J. Araki, A. Uchida T. Kishi- Vidensk. Selsk. Skr., (6), 4: 316–322, 1pl. ro & K. Nagasawa, 1996. Minke whales (Balaenoptera Margolis, K., 1954. Three kinds of whale lice (Cyamidae: acutorostrata) are one of the major final hosts of Amphipoda) from the Pacific coast of Canada, includ- Anisakis simplex(Nematoda: Anisakidae) in the north- ing a new species. J. Fish. Res. Bd. Canada, 11: 319– western North Pacific Ocean. Rep. Int. Whal. Commn., 325. (46): 415–419. Margolis, L., 1955. Notes on the morphology, taxonomy Leung, Y. M., 1965. A collection of whale-lice (Cyami- and synonymy of several species of whale lice (Cyami- dae: Amphipoda). Bull. S. Calif. Acad. Sci., 64: 132– dae: Amphipoda). J. Fish. Res. Bd. Canada, 12: 121– 143. 133. Leung, Y. M., 1967. An illustrated key to the species of Margolis, L., T. E. McDonald & E. L. Bousfield, 2000. whale lice (Amphipoda, Cyamidae), ectoparasaites of The whale lice (Amphipoda: Cyamidae) of the north- Cetadcea, with a guide to the literature. Crustaceana, eastern Pacific region. Amphipacifica, 2: 63–117. 12: 279–291. Roussel de Vauzème, A., 1834. Memoire sur le Cyamus Leung, Y. M., 1976. Life cycle of Cyamus scammoni ceti(Latr.) de la classed des Crustaces. Ann. Sci. Nat., (Amphipoda: Cyamidae), ectoparasite of gray whale, Zool., (2), 1: 239–255, 257–265. with a remark on the associated species. Sci. Rep. Zenkovitch, B. A. 1934. Materialy k poznaniyu kitoo- Whale Res. Inst., (28): 153–160. braznikh db morey (Seryy kaliforniyskiy kit-Rhachi- Lütken, C. F., 1870. Conspectus Cyamidarum borealium anectes glaucus Cope). Vest. Akad. Nauk SSSR, (10): hujusaue cognitarum. Vidensk. Selsk. Forhandl. Chris- 9–25. (In Russian.) tiania, 13: 279–280. (In Danish.) Zenkovitch, B. A., 1937. Yeshche o serom kaliforniyskom Lütken, C. F., 1873. Bidrag til Kundskab om Arterne af kite (Rhachianectes glaucus Cope, 1864). Vest. Akad. Slaegten CyamusLatr. eller Hvallusene. Vidensk. Selsk. Nauk SSSR, (23): 91–103. (In Russian.)