ONDO, Yoshinori Biological Laboratory, Faculty of Liberal Arts, Tottori University
OHKI, Mitsuru Biological Laboratory, Faculty of Liberal Arts, Tottori University
FUKUDA, Keiko Biological Laboratory, Faculty of Liberal Arts, Tottori University
1. Hydrobiological studies have been carried out on the Rotifera populations of Koyama River, from October, 1962 to November, 1963.
2. Throughout the year, 22 species of Rotifera are recorded and among them, Keratella valga and Keratella cruciformis war eichwaldi are usually inhabited the Koyama River, either abundantly or scantly.
3. The number of species appeared in a year tends to show its maximum abundance at Station 3 (Karo-bashi) on one hand, and on the other hand, the total of individual numbers of rotifers in the most prevalent at Station 1 (Ido-bashi). Distinct differences with regard to the appearance of rotifers can be observed. In general, the number of individuals in each Rotifera population decreases towards downstream.
4. In Koyama River, Keratella crucifoemis var. eichwaldi and Notholuca acuminata as a brackish species and those of freshwater, e.g. , Diaphanosoma brachyurum, Trinchocerca longiseta, Keratella cochlearis or Pedalia mira are also found out at the same time.
5. In each season, the following species are dominant over all species. They are as follows : Polyarthra vulgaris, Trichocerca sp. and Pedalia mira in a prevernal period, P. vulgaris in a vernal period, but P. vulgaris and Keratella valga appeared abundantly in an autumnal period. Even, in a himal period, P. vulgaris and K. valga tend to show the appearance of considerable frequency. However, Keratella cruciformis var. eichwaldi is the dominant over all rotifers in an estival period, being appeared throughout the year.
鳥取大学学芸学部研究報告. 自然科学. 1954, 15, 121-132