Life History of A. japonica

Presentation on theme: "Life History of A. japonica"— Presentation transcript:

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

2 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

3 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)

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

5 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?

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7 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

8 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

9 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 oE The latitude of the NEC bifurcation: where 2o longitude averaged meridional velocity east of the Philippine coast is zero

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

12 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

13 Conditions for larval migration model
1Shinoda (2004), Tsukamoto et al. (2003); Kumura et al. (2001) Castonguary 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)

14 Transport of A. japonica leptocephali

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

16 Recruitment to Japanese coasts
Shinoda (2004)

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

18 2004 2005

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20 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