マベ貝鰓の繊毛運動に及ぼす水温の影響

Abstract

The present paper aims to make a few contributions to actual culture of black banded wings pearl oyster, Pteria penguin (RODING), which is known for producing extra-fine pearls, describing a phase of life of this shell-fish reflected in the. ciliary motion of gill at different temperatures. The method adopted in this experiment was analogous to that of YUKI7), the arrangement of the apparatus being outlined in Fig. 1. The filtered sea water used was of pH=8.3 with a salinity of 25.2. The results say, as indicated by Table 1 and Fig. 2, the ciliary movement is quite insignificant at temperatures below 19°C. but grows rather vigorous as the water warms up to 21°C. The motion becomes very sprightly between 23°C. and 33°C., attaining to an optimum at 25°C. Though the motion slows down rapidly at temperatures beyond 33°C., it does not cease even at 35°C. Generally speaking, physiological activity of the oyster hesitates to be restored during the period of temperature rise and hastens to draw back with temperature fall of the surrounding water. The implied characteristics of slow awaking in spring and rapid sleeping in autumn call upon the usual method of culturing the oyster to be looked at once more. Since the present experiment shows a sudden rise in ciliary movement occurring between 21°C. and 23°C., the latter temperature may be expected in various points to serve as an indicator of a critical condition in the culture of this shell-fish.