| Abstrakt: |
Eodiaptomus japonicus was collected in the north basin of Lake Biwa, Japan, on six dates from 11 to 25 June 1987. Temporal changes in its vertical distribution and reproduction indices were small, but those in its abundance were large. Mortality was high in the naupliar stage I and from copepodid stage III to adult stage. The latter fact and low proportion of females in adulthood suggest heavy predation by fishes which prefer larger prey. Eodiaptomus japonicus showed ontogenetic vertical migration within the epilimnion. The direction of the migration was upward in the early naupliar stages and downward in the late naupliar and early copepodid stages. Both migrations resulted in raising mortality in the corresponding or succeeding stages, probably expressing the behavioral constraints of E. japonicus. [ABSTRACT FROM AUTHOR] |
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