抄録
Chlorinities limiting the living of Styela were examined by culturing them in various stages in sea waters. From its results and data of oceanographical observations, some influences of the rainfall on Styela in Sakibe Inlet at Sasebo Bay were discussed.
1) Their larvae and attached ones are caused to death within 48 hours in the sea waters less than about 15‰, and 14‰ in chlorinity at 20°C, respectively. Therefore, their penetrations are probably checked in waters which chlorinity concentration frequently decrease below 16‰ during the period from spring to autumn.
2) In Sakibe Inlet, the rainfall usually lowers the chlorinity of sea water of 0-2m layers. In the continuous heavy rainfalls (over 100mm/day) wnich occur generally between July to September, the chlorinity of surface water decrease lower than 14‰.
3) Styela attached on the immersed substrata in the surface layer were suffered from the critical limiting effects of the low chlorinity caused by heavy rains, but in deeper layers than 2 meters there were little influence.
