@article{oai:nipr.repo.nii.ac.jp:00010227,
 author = {Ono, Atsushi and Moteki, Masato and Amakasu, Kazuo and Toda, Ryoji and Horimoto, Naho and Hirano, Daisuke and Ishimaru, Takashi and Hosie, Graham W. and Ono, Atsushi and Moteki, Masato and Amakasu, Kazuo and Toda, Ryoji and Horimoto, Naho and Hirano, Daisuke and Ishimaru, Takashi and Hosie, Graham W.},
 issue = {2},
 journal = {Polar science, Polar science},
 month = {Aug},
 note = {The distribution and community structure of euphausiids and the population structure of Euphausia superba were investigated mainly along 140°E off Adelie Land in the Indian Ocean sector of the Southern Ocean during the austral summers of 2003, 2005 and 2008. Euphausiids were collected from six discrete depth layers, primarily between 0 and 2000 m, using an RMT 8 net. Euphausia frigida and Euphausia triacantha mainly occurred north of the Southern Boundary of the Antarctic Circumpolar Current (SB) whereas E. superba was distributed south of the SB, and occurred abundantly in the continental slope area where Antarctic Winter Water was observed. E. frigida and E. triacantha occurred in the upper 200 m during the night whereas they were mainly found below 200 m during the daytime. Cluster analysis on stations suggested that the SB is an important biological boundary for euphausiid communities. The population structure of E. superba in 2003 was different from that of 2005 and 2008. While large mature individuals dominated in 2003, small immature krill (juveniles and subadult males) were more abundant in 2005 and 2008. Further sea-ice extension in the preceding winter in 2005 and 2008 likely provided favourable conditions for spawning and survival. A cluster analysis based on similarity of the maturity stages of E. superba revealed that mature males and gravid females (stage IIIC–E) were mainly distributed in the offshore area and mesopelagic zone, while juveniles and subadult males were found in the epipelagic zone of the continental slope area. Therefore, it is considered that E. superba migrates to the offshore area and mesopelagic zone as it grows., 2003, 2005および2008年夏季の南大洋インド洋セクターアデリーランド沖におけるオキアミ類の群集構造とEuphausia superbaの個体群構造を明らかにした。E. frigidaとE. triacanthaは主に南極周極流の南縁 (Southern Boundary of the Antarctic Circumpolar Current: SB) の北側で優占したのに対し，E. superbaはSBの南側，特にAntarctic Winter Waterの見られた陸棚斜面域で卓越した。2003年におけるE. superbaの個体群構造は，2005年および2008年とは異なった。これは観測前年度冬季の海氷張り出しが影響したと考えられる。クラスター解析の結果，adult maleとgravid female (IIIC–E) が主に沖合域や中・深層に分布するのに対し，juvenileとsubadult maleは陸棚斜面域の表層に分布することが明らかになった。以上のことから，E. superbaは成熟するに従い，沖合域や中・深層へ移動することが示唆された。},
 pages = {146--165},
 title = {Euphausiid community structure and population structure of Euphausia superba off Adelie Land in the Southern Ocean during austral summer 2003, 2005 and 2008},
 volume = {5},
 year = {2011}
}