Diel vertical migration of Euphausia pacifica (crustacea, euphausiacea) in relation to molt and reproductive processes, and feeding activity |
| |
| Authors: | Yoshinari Endo Fuhito Yamano |
| |
| Institution: | (1) Laboratory of Aquatic Ecology, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan;(2) Present address: Environment and Quality Control Group, The Maruha Group Inc., 1-1-2, Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan |
| |
| Abstract: | We investigated the diel vertical migration of Euphausia pacifica in relation to molt and reproductive processes and feeding activity in April and September 2001 at fixed stations off northeastern
Japan. The vertical distribution of this species was shallower in April than in September during both day and night, which
was partly explained by a high surface temperature (19°C) and the existence of a subsurface chlorophyll maximum in September.
It has been demonstrated for the first time that diel vertical migration of this species is influenced by molt processes because
upward migration of molting individuals was restricted compared with non-molting ones. Feeding activity of molting individuals
was reduced throughout the day, being lower than or similar to the daytime feeding activity of non-molting ones. The percentage
of molting individuals was least (2–4%) among the gravid females, which suggests that gravid females molt less frequently
than other stages of females and males. Molt and reproductive processes therefore seemed to be coupled in this species. |
| |
| Keywords: | DVM molt cycle maturity feeding Euphausia pacifica |
| 本文献已被 SpringerLink 等数据库收录！ |
|
