Life history ofEuphausia similis (crustacea,euphausiacea) in Sagami Bay,central Japan |
| |
| Authors: | Yuichi Hirota Takahisa Nemoto Ryuzo Marumo |
| |
| Institution: | (1) Japan Sea National Fisheries Research Institute, Suido-cho, 951 Niigata, Japan;(2) Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano-ku, 164 Tokyo, Japan;(3) Nodai Research Institute, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, 156 Tokyo, Japan |
| |
| Abstract: | The life history ofEuphausia similis G.O. Sars in Sagami Bay, central Japan, has been studied by examining the abundance, size distribution, and occurrence of each growing stage from egg to adult. Three cohorts were laid within the period from July 1979 to July 1980. Individuals of cohort I of 1980 were laid in November and December 1979, and matured and spawned in March and April of the following year. Those of cohort II of 1980 laid in January and February 1980 should mature in November and spawn after December, by analogy with cohort II of 1979. Cohort III of 1980 was laid in April 1980, but decreased in number in July. Cohort II was the dominant cohort in Sagami Bay throughout the period studied. From December 1979 to April 1980 when the mixing layer was present, many eggs ofE. similis were in the epipelagic zone. It is suggested that the spawning season ofE. similis roughly coincided with the season of active feeding, indicated by high fullness of stomachs in individuals. The production of juveniles and adults was about 1.33 mg C m–2 day–1, and the production to bio mass (P/B) ratio was estimated to be 4.78 between July 1979 and July 1980. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
