Abstract
A model that helps explain the mysterious long-distance migration of the Japanese eel (Anguilla japonica) is presented, based on oceanographic observations, satellite buoy drift experiments, and samplings of eel larvae taken in 1991. The trajectory of a 150 m depth buoy relased in the spawning area strongly suggests that A. japonica larvae spawned just south of the salinity front are transported westward by the North Equatorial Current (NEC). The larvae are then thought to be entrained into the Mindanao Current flowing southward along the Philippine Islands where A. japonica juveniles are scarcely distributed. These controversial results lead to the assumption that eel larvae are transferred from the NEC to the northward flowing Kuroshio, which distributes the eel larvae to the growth habitats of eastern Asia. In this eel larvae transfer model, a northward Ekman transport caused by trade winds plays an important role in explaining the wind-induced northward shift of the larvae together with the onset of diel vertical migration. Assuming that leptocephali greater than 20 mm initiate the vertical migration, a westward wind velocity greater than 5 to 10 m s-1 should be high enough to diminish the southward current velocity. When the physical and geophysical conditions — such as the salinity front for spawning activity, the water tunnel for westward larval transport, the Ekman transport by the trade wind for transfer of the larvae from the NEC to the Kuroshio, and the strong velocity of the Kuroshio for rapid transport to growth habitats — are well matched with the timing of the onset of vertical migration, large-scale eel migration could result.
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References
Castonguay M, McCleave JD (1987) Vertical distribution, diel and ontogenetic vertical migrations and net avoidance of leptocephali of Anguilla and other common species in the Sargasso Sea. J Plankton Res 9:195–214
De Szoeke RA (1980) On the effects of horizontal variability of wind stress on the dynamics of the ocean mixed layer. J phys Oceanogr 10: 1439–1454
Hasunuma K, Yoshida K (1978) Splitting of the subtropical gyre in the western north Pacific. J Oceanogr Soc Japan 34: 160–172
Japan Meteorological Agency (1987) The results of marine meteorological and oceanographical observations 79. Japan Meteorological Agency, Tokyo
Japan Meteorological Agency (1988) The results of oceanographical observations 80. Japan Meteorological Agency, Tokyo
Japan Meteorological Agency (1989) The results of oceanographical observations 81. Japan Meteorological Agency, Tokyo
Japan Meteorological Agency (1990) The results of oceanographical observations 82. Japan Meteorological Agency, Tokyo
Kajihara T (1988) Distribution of Anguilla japonica leptocephali in the Western Pacific during September 1986. Nippon Suisan Gakk 54:929–933
Kajihara T, Tsukamoto K, Otake T, Mochioka N, Hasumoto H, Oya M (1988) Sampling leptocephali with reference to the diel vertical migration and the gears. Nippon Suisan Gakk 54:941–946
Kleckner RC, McCleave JD (1982) Entry of migrating American eel leptocephali into the Gulf Stream system. Helgoländer Meeresunters 35:329–339
Kleckner RC, McCleave JD (1988) The northern limit of spawning by Atlantic eels (Anguilla spp.) in the Sargasso Sea in relation to thermal fronts and surface water masses. J mar Res 46:647–667
Kutsuwada K (1987) Monthly maps of surface wind stress fields over the north Pacific during 1961–1984. Bull Ocean Res Inst Univ Tokyo 24:1–100
Maritime Safety Agency of Japan (1986) Data report of hydrographic observations: series of Westpac 1. Maritime Safety Agency of Japan, Tokyo
Maritime Safety Agency of Japan (1988) Data report of hydrographic observations: series of Westpac 2. Maritime Safety Agency of Japan, Tokyo
Maritime Safety Agency of Japan (1988) Data report of hydrographic observations: series of Westpac 3. Maritime Safety Agency of Japan, Tokyo
Matsui I (1955) On the species and distribution of Japanese eels collected in the Pacific region and its adjacent waters. Bull biogeographical Soc Japan 16–19:282–292
Ozawa T, Kakizoe F, Tabeta O, Maeda T, Yuwaki Y (1991) Japanese eel leptocephali from three cruises in the Western North Pacific. Nippon Suisan Gakk 57:1877–1881
Ozawa T, Tabeta O, Mochioka N (1989) Anguillid leptocephali from the western North Pacific east of Luzon, in 1988. Nippon Suisan Gakk 55:627–632
Pickard GL, Emery WJ (1982) Descriptive physical oceanography. Pergamon Press, Oxford
Roden GI, Paskausky DF (1978) Estimation of rates of frontogenesis and frontolysis in the North Pacific Ocean using satellite and surface meteorological data from January 1977. J geophys Res 83:4545–4550
Schmidt J (1925) The breeding places of the eel. A Rep Smithsonian Inst 1924:279–316
Schoth M, Tesch FW (1982) Spatial distribution of 0-group eel larvae (Anguilla sp.) in the Sargasso Sea. Helgoländer Meeresunters 35:309–320
Schoth M, Tesch FW (1984) The vertical distribution of small 0-group Anguilla larvae in the Sargasso Sea with reference to other Anguilliform leptocephali. Meeresforschung 30:188–195
Tabeta O (1981) On the early life history of Japanese eel with reference to the spawning ground. Aquabiology, Tokyo 3:412–417 (in Japanese with English abstract)
Tabeta O, Konishi Y (1986) An anguillid leptocephalus Anguilla japonica from the waters south of Miyako Island, Okinawa, Japan. Bull Japan Soc Sci Fish 52:1935–1937
Tabeta O, Mochioka N (1988) Anguillid leptocephali from the waters south of Okinawa and east of Taiwan and Luzon, Western North Pacific, in 1986. Nippon Suisan Gakk 54:935–940
Tabeta O, Takai T (1975) Leptocephalus of Anguilla japonica found in the waters south of Taiwan, Japan J Ichthyol 22:100–103
Tabeta O, Takai T (1975) Record of the Japanese eel from the Philippines. Bull Japan Soc Sci Fish 41:641–644
Takai T, Tabeta O (1976) Anguillid leptocephali. In: Ishi T (ed) Preliminary report of the Hakuho-Maru Cruise KH-75-1 (Ocean Research Institute, University of Tokyo, 1976). University of Tokyo, Tokyo, pp 12–13
Tanaka S (1975) Collection of leptocephali of the Japanese eel in waters south of the Okinawa Island. Bull Japan Soc Sci Fish 41:129–136
Tsukamoto K (1992) Discovery of the spawning area for Japanese eel. Nature, Lond 356:789–791
Tsukamoto K, Umezawa A, Tabeta O, Mochioka N, Kajihara T (1989) Age and birth date of Anguilla japonica leptocephali collected in western North Pacific in September 1986. Nippon Suisan Gakk 55:1023–1028
Welander P (1981) Mixed layers and fronts in simple ocean circulation models. J phys Oceanogr 11:148–152
Wyrtki K, Meyers G (1975a) The trade wind field over the Pacific Ocean, Part 1. Hawaii Institute of Geophysics, University of Hawaii, HIG-75-1
Wyrtki K, Meyers G (1975b) The trade wind field over the Pacific Ocean, Part 2. Hawaii Institute of Geophysics, University of Hawaii, HIG-75-2
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Communicated by T. Ikeda, Nagasaki
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Kimura, S., Tsukamoto, K. & Sugimoto, T. A model for the larval migration of the Japanese eel: roles of the trade winds and salinity front. Marine Biology 119, 185–190 (1994). https://doi.org/10.1007/BF00349555
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DOI: https://doi.org/10.1007/BF00349555