Fisheries Science 60(5), 515-518 (1994)

Distribution of White Shark in Japanese Waters

Kazuhiro Nakaya

Laboratory of Marine Zoology, Faculty of Fisheries, University, Minato, Hakodate, Hokkaido 041,

(Received December 14, 1993)

The white shark was thought to be rare in Japanese waters except Okinawa, but the author doubted its rarity because of its coastal and temperate habitat and eurythermal nature. Therefore, records of large sharks were collected since 1992 and closely examined. Nineteen of sharks were the white shark Carcharodon carcharias, and such a high incidence in catches or sightings in only 18 months is surprising , because previous published records indicate for fewer numbers. Since many of the larger sharks are not landed because of their low commercial value, and since smaller specimens were not included in this survey, the white shark is not a rare species in Japan. The white shark is known to exist in waters of 7 to 27•Ž (mainly 15 to 22•Ž), and its eurythermal

nature suggests that the species can remain all year round in the southern and middle parts of Japan.

However, the white shark seems to be a seasonal visitor to the waters of northern and Hokkaido.

Key words: white shark, Carcharodon carcharias, occurrence, migration, shark attack, catch records, Japanese waters

The white shark Carcharodon carcharias is primarily a fishermen's cooperatives, and news of large sharks reported in by the coastal and temperate water species, and grows to more media. Whenever the capture of a large shark was reported, materials were than 6 meters in total length. The white shark is generally gathered in order to identify the species such as by examining the specimen, teeth, and photographs. Two cases were identified by Senzo Uchida of the considered to be rather rare in Japanese waters because of Okinawa Expo Memorial Aquarium. Body sizes of the shark were their scarcity in capture records. Nakano and Nakaya1) measured or estimated by non-specialists in most cases, and body weight found very few published records of white shark in Japan. was roughly estimated by fishermen. On March 8, 1992, a professional shell diver was attacked by a large shark at , Ehime Prefecture, and the Results and Discussion shark was later identified to be a white shark (Nakaya2)). However, this fatal shark attack at Matsuyama caused Nineteen captures or sightings of white sharks occurred widespread public concern, and the TV, newspaper, and during the period of this survey from March, 1992 through other mass media became interested in reporting captures August, 1993. The localities and catch data are summarized and discoveries of large sharks. Since then, they have begun in Table I and Fig. 1. Ten came from the Pacific side of to report news of large sharks from various parts of Japan, the Japanese archipelago, four from the , including that of the white shark. There have apparently and five from the Japan Sea side. As shown in Table 1, been other attacks by very large sharks or underwater most of the individuals were caught by set nets, but the encounters with large sharks in the Seto Inland region, and fishermen who work the set net fisheries report that large most of these appear to have been the white shark based individuals are often released from the net or discarded on the water temperature at the time of the incidents and offshore because of the shark's low commercial value and the victim's verbal accounts of the attacker shark. These the danger of handling. Smaller individuals were also not facts indicate that the white shark is much more common included in this survey because they tend to be overlooked in Japanese waters than has been previously supposed. or go unreported. The actual number of white sharks An extensive survey of the white shark in the Japanese captured is thus likely to be higher than the data given here. waters was thus conducted, while the mass media were in Although Nakano and Nakaya2) reported 12 previous terested in the capture of large sharks. Scientifically, it is published records of the white shark in Japanese and its worthwhile summarizing recent captures of the white shark adjacent waters, these represent only a fraction of actual because of the complete lack of biological knowledge about white shark captures. the white shark in Japanese waters. Socially, the white shark Present records show that white shark were caught or poses a great danger to divers and fishermen of southern observed from March to July and in December in 1992, Japan, and gathering data on its occurrence may reveal its and in January, March, April, and August in 1993, in distribution and seasonal migration in Japanese waters which dicating that white shark are captured in spring, summer, should be useful for dealing with the white shark threat. and winter. It is difficult to discuss their seasonal move ments in Japanese waters because of the limited amount of Methods data available. However, as they migrate seasonally (Casey and Pratt,4) Klimley,5) Bruce,6)), and their seasonal

Information on the capture of large sharks was collected from various migration is at least partly influencedby surface temperature universities, fisheries laboratories, local fisheries experimental stations, (Casey and Pratt4), it is possible to predict their occurrence 516 Nakaya

Table 1. Occurrence of white shark from March, 1992 to August, 1993 in Japanese waters

*1: See Nakaya2) for details . *2: Figure 2 . *3: Data taken by shark specialists, *4: See Shimamoto et al .1) for details.

Fig. 1. N Capture or sighting of the white shark in Japanese waters from March , 1992 to August, 1993. umerals (1 to 19) show the localities and numbers referenced in the text and Table 1. Distribution of White Shark in Japan 517

Fie. 2. White sharks captured during the present survey. Above: Sata specimen (No. 2), Below: Ishinomaki specimen (No. 9).

and migration in relation to the surface water temperature. 68 years at Shiokubi-misaki on the south western coast of

Casey and Pratt4l reported that the white shark is found in Hokkaido is below 7•Ž from January to April, 8.0•Ž in waters from 11ß to 24•Ž with 75% occurring when the May, goes up above 11 •Ž from June to November, and

surface temperature is between 15ß and 22•Ž. Nakano and falls to 9.5•Ž again in December. If 7•Ž is the lowest Nakayatl reported a white shark in waters of 7.2•Ž, which temperature for the white shark, then considering water is the lowest record for the species. temperature only, the species may remain in the coastal According to Tomosada,7) the average surface water waters of the south and middle Japan regions south of temperature never falls below 11 •Ž south of Katsuura, Shioya-saki and Nyudo-zaki (Fig. 1) throughout the year. on the Pacific, and Jizo-misaki, Shimane According to S. Uchida, 13 individuals were caught in Prefecture in the Japan Sea (Fig. 1; south Japan). It falls the waters of Okinawa from 1975 to 1990, two in January below 11 •Ž but not below 7•Ž from Choshi, Chiba and February, one in March and June, three in August, Prefecture to Shioya-saki, on the and four in November. These records from Okinawa suggest

Pacific coast and from Kyou-ga-misaki, that the white shark is present all year round in these waters. to Nyudo-zaki, on the Japan Sea coast The water temperature at the time of capture of the Okinawa (middle Japan). The water temperature falls below 7•Ž in specimens ranged between 21.1•Ž and 27.4•Ž. Sixteen of the more northern parts of Honshu and Hokkaido (north the 19 records in this paper came from south Japan, Japan). For example, the average surface temperature over where the average water temperature is always higher than 518 Nakaya

11•Ž. Together with other records from south Japan in S. Kuwabara (Ehime Prefecture), Messers N. Tanaka and H. Semura Uyeno and Matsushima,8) Mochizuki and Nose,9) Nakano (Shimane Prefectural Fisheries Experimental Station), Drs. K. Tabata and and Nakaya,1) Teshima, * 1 and two specimens caught at N. Shimamoto (Hyogo Prefectural Fisheries Experimental Station), Mr. K. Hojo in July, 1982 (unpublished data), white shark have Maruyama (), Mr. S. Hagiwara (Shimoda Floating Aquarium), Drs. K. Mochizuki and M. Miya (Chiba Central Museum), been captured in all months except September and October, Messers T. Chiba and S. Yamaoka (), Dr. Kunio Amaoka suggesting that the species is present throughout the year (Hokkaido University), Takano Reizo Co. (Yoichi, Hokkaido), Ehime in this region. The remaining three records, and the two Shimbun (Matsuyama), Minami-Nihon Shimbun (Kagoshima), Bohnichi individuals reported by Nakano and Nakaya2) in north Shimbun (Tateyama, Chiba), Hokkaido Shimbun (Hakodate), Hokkai Japan were captured in April, May, and June, and no Times (Sapporo). specimen has been reported in the colder months when the References water temperature stays below 7•Ž. Judging from the temperature preference, the white shark is thought to leave 1) H. Nakano and K. Nakaya: Records of the white shark Carcharodon north Japan in the colder months. carcharias from Hokkaido, Japan. Japan. J. Ichthyol., 33, 414-016 Of present 19 individuals, nine were males, five were (1987). females, and five were unknown. At least six males (Nos. 2) K. Nakaya: A fatal attack by a white shark in Japan and a review 2, 7, 9, 13, 15, and 19) had fully developed claspers. Three of shark attacks in Japanese waters. Japan. J. Ichthyol., 40, 35-42 females (Nos. 5, 6, and 8) were mature, and two of them (1993). caught at Kagoshima (No. 5) and Kochi (No. 6) in May 3) N. Shimamoto, M. Tanda, Y. Nakamura, T. Otani, T. Nishikawa, were pregnant, with five embryos of about 1.3m in total K. Tabata, K. Tange, T. Mori, and K. Hatooka: Record of the white shark Carcharodon carcharias caught in Sea of Harima in May, length (TL) and ten embryos of 1.35 to 1.51 m TL, 1992. Hyogo Suishi Kenpo, 31, 79-84 (1994). respectively. Cailliet et a1.10)estimated the size of the white 4) J. G. Casey and H. L. Pratt, Jr: Distribution of the white shark, shark at birth to be approximately 1,25m TL, and these Carcharodon carcharias, in the western North Atlantic. Mem. South embryos in the Nos. 5 and 6 specimens were a little larger Calif. Acad. Sci., 9, 2-14 (1985). than this estimated birth size. Therefore, these pregnant 5) A. P. Klimley: The areal distribution and autoecology of the white females are considered to have been almost at the stage of shark, Carcharodon carcharias, off the west coast of North America, Mem. South Calif. Acad. Sci., 9, 15-40 (1985). parturition. Uchida et al. *2 reported one pregnant white 6) B. D. Bruce: Preliminary observations on the biology of the white shark with seven near-term embryos of 1.0 to 1.1 m TL shark, Carcharodon carcharias, in South Australian waters. Aust. J from Taiji, Wakayama Prefecture on April 2, 1986. These Mar. Freshwater Res., 43. 1-11 (1992). pregnant females were alll caught along the Pacific coast of 7) A. Tomosada: Monthly mean data of air and sea surface temperatures south Japan in April and May, and these may support measured at the coast since 1910 by assigning to light houses and the spring-summer parturition of the species suggested by fisheries experimental stations. Datum Coll. Tokai Reg. Fish . Res. Bruce,6) Further, the occurrence of the near-term females Inst., 10, 1-36 (1982). 8) T. Uyeno and Y. Matsushima: Comparative study of teeth from in these geographically close places suggest the location of Naganuma Formation of Middle Pleistocene and recent specimens parturition in Japanese waters. The other mature female of the great white shark, Carcharodon carcharias from Japan . Bull. from Furubira, Hokkaido (No. 8) carried no embryos, but Kanagawa Pref. Mus. (Nat. Sci.), 11, 11-30 (1979). had many bleeding mating scars on the body, suggesting 9) K. Mochizuki and Y. Nose: Catalogue of the Pisces specimens the time of copulation in this species. preserved in the Department of Fisheries, the University Museum, the University of (1). University Museum, University of Tokyo Material Rep., 14, 1-123 (1986). Acknowledgements The author wishes to thank the following persons and 10) G. M. Cailliet, L. J. Natanson, B. A. Welden companies for their advice, information on captures of white shark and , and D. A. Ebert: Preliminary studies on the age and growth of the white shark, photographs of specimens: Dr. S. Uchida and Mr. M. Toda (Okinawa Carcharodon carcharias, using vertebral bands Expo Memorial Aquarium), Dr. A. Shinomiya (Kagoshima University), . Mem. South Calif. Acad. Sci., 9, 49-60 (1985). Dr. T. Kanda (Miyazaki University), Messers Y. Akazaki, K. Shiota and

*1 K . Teshima: Classification and ecology of sharks. Record of Forum "Sharks , its ecology and ethology." Seto Inland Sea Fish. Dev . Congr., 1992 , pp. 9-34 (in Japanese). *2 S. Uchida, F. Azumi, M. Toda, and N. Ookura: Reproduction of white shark and mako shark . Abstract of Symposium on systematics ecology and physiology of Elasmobranchs , . Ocean Research Institute, University of Tokyo, 1987 , pp. 3-4.