Effect of El Niño on migration and transport of the Japanese eel, Anguilla japonica

Life History of A. japonica Leptocephalus Egg Yellow eel Elver Silver eel Grass eel 外洋域・産卵場 淡水域・成育場 Life History of A. japonica An object of study

뱀장어목(Anguilliformes), 뱀장어과(Anguillidae) Representative catadromous species Spawning site Around 14oN, 142oE, to the west of the Suruga Seamount in the southern part of the West Mariana Ridge (Tsukamoto, 2006) Migration & Transport Recruit to the coasts of East along the NEC and the Kuroshio (Kimura, 1994)

KH06-2 Eel Cruise During about 40 years from the first collection of A. japonica leptocephali 3 Sep. 2006

태평양과 대서양에서 뱀장어의 가입의 감소 Q) 지역상 다른 두 ocean basin에서 동시적인 가입감소의 원인은? European eel (FAO) 대서양(American eel & European eel)과 태평양(Japanese eel) 뱀장어의 가입은 지속적 감소경향 감소원인: pollution, habitat loss, climatic change, overexploitation Q) 지역상 다른 두 ocean basin에서 동시적인 가입감소의 원인은?

transport to the Kuroshio Salinity front Change of ocean systems in the NEC region 2Kim et al. (2004) Qu & Lukas (2003) 1Kimura et al.(2001) southernmost northernmost 15.5 ˚N transport to the Kuroshio NEC bifurcation2 16 ˚N spawning site Salinity front1 La Niña El Niño Normal Effect

Variation of Southern Oscillation Index (SOI) El Niño Purpose of Study Through understanding the effect of El Niño on a migration and transport of A. japonica larvae (leptocephali), it is discussed that the difference of recruitment to continental habitats in East Asia

Ocean model for the Earth Simulator (OFES) Based on the Modular Ocean Model (MOM3) Model domain : a near-global region extending 75 oS to 75 oN Horizontal grid spacing : 0.1 degree Applied flow fields for lagrangian trajectories: with a 3-day interval Referred from Masumoto et al. (2004), Sasaki et al. (2006) Definition of the location of the salinity front and the NEC bifurcation Salinity front: determined by 34.5 psu using salinity averaged within the mixed layer ranging from the surface to 30 m depth in a zonal range of 137-142oE The latitude of the NEC bifurcation: where 2o longitude averaged meridional velocity east of the Philippine coast is zero

Interannual variability of the NEC bifurcation El Niño Non-El Niño (12-month moving average)

엘니뇨 현상과의 time lag: Kimura et al. (2001), Kim et al 엘니뇨 현상과의 time lag: Kimura et al. (2001), Kim et al. (2004) 염분전선(5 months), 북적도 해류의 분지(1 month) Non-El Niño El Niño

Conditions for larval migration model 1Shinoda (2004), Tsukamoto et al. (2003); 2Kumura et al. (2001) 3Castonguary and McCleave (1997); Otake et al. (1998); Kajihara et al. (1988) 1spawning season : May to December (new moon) 2spawning site : change according to the climate change 3diel vertical migration : 150 (day)/50 (night)

Transport of A. japonica leptocephali

Catch of the glass eel in the Kagoshima Prefecture La Niña Non-El Niño El Niño

Recruitment to Japanese coasts Shinoda (2004)

Distribution of A. japonica leptocephali Photos of pre-leptocephali (Tsukamoto, 2005) Leptocephalus (a) (b) (c)

2004 2005

NEC bifurcation, 염분전선의 경년 변동 결론 A. Pacific scale: 기후변동(엘니뇨) NEC bifurcation, 염분전선의 경년 변동 동아시아에서의 뱀장어의 가입량의 변동 B. Meso-scale: Eddy의 형성 뱀장어 자어의 분산과 집적 회유, 수송시간의 지연 NEC