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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Fisheries Sciences / Faculty of Fisheries Sciences >
北海道大学水産科学研究彙報 = Bulletin of Fisheries Sciences, Hokkaido University >
第64巻 第3号 >
Short-term changes in the population structure of hydromedusa Aglantha digitale during the spring phytoplankton bloom in the Oyashio region
| Title: | Short-term changes in the population structure of hydromedusa Aglantha digitale during the spring phytoplankton bloom in the Oyashio region |
| Authors: | Abe, Yoshiyuki Browse this author | | Yamaguchi, Atsushi Browse this author →KAKEN DB | | Matsuno, Kohei Browse this author →KAKEN DB | | Kono, Tokihiro Browse this author | | Imai, Ichiro Browse this author →KAKEN DB |
| Keywords: | spring bloom | | hydromedusae | | water mass | | growth rate |
| Issue Date: | 15-Dec-2014 |
| Publisher: | 北海道大学大学院水産科学研究院 |
| Journal Title: | 北海道大学水産科学研究彙報 |
| Journal Title(alt): | Bulletin of Fisheries Sciences, Hokkaido University |
| Volume: | 64 |
| Issue: | 3 |
| Start Page: | 71 |
| End Page: | 81 |
| Abstract: | To evaluate the effects of water mass changes and the spring phytoplankton bloom, we analysed short-term changes in the population structure of the dominant hydromedusa Aglantha digitale in the Oyashio region during March-April 2007. Samples were collected with Bongo nets at night via oblique towing from a depth of 200 m to the surface on eight occasions in March and April of 2007. The abundance, biomass and mature individual compositions of A. digitale rapidly increased from April onward. During April, the reproduction and growth of A. digitale is achieved due to the initiation of the spring phytoplankton bloom and the increase in small copepods. Based on dry mass, the growth rate of A. digitale (1.3% day-1) was lower than the reported maximum value (4.9% day-1) for this species. The rapid exchange of the dominant water masses was also observed during spring in the Oyashio region. Significant effects of water mass exchange were detected in the abundance, biomass and body sizes of A. digitale. Thus, the abundance, biomass and population structure of A. digitale in the Oyashio region may be altered during spring by two factors : internal growth and external water mass exchange. |
| Type: | bulletin (article) |
| URI: | http://hdl.handle.net/2115/57517 |
| Appears in Collections: | 北海道大学水産科学研究彙報 = Bulletin of Fisheries Sciences, Hokkaido University > 第64巻 第3号
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