抄録
The response of Bugula neritina in the colonial growth of the early stage to the water temperature was examined by culturing colonies in one-liter beakers at various water temperatures of 5, 10, 13, 15, 19, 22, 25, 28, 30 and 32°C. Colonies consisting of one zooid attached to slide glasses were placed in the beaker with 800ml of food plankton suspension adjusted at the density of 10, 000cells/ml. Food suspension was made by diluting the dense stock suspension with the filtered sea water. We renewed food suspension every day, and counted the zooid number of each colony every few days to estimate the intrinsic rate of the increase of zooids number which numbered between 3-200.
Although the colonies cultured at lower than 10°C did not increase their zooid number, they were able to stay alive for more than one week. They grew in the laboratory as fast as in the natural sea where the water temperature was between 13°C and 22°C, but the growth speed in the laboratory was low at greater than 25°C compared with that in the natural sea. At 30 and 32°C, they could grow well for only a few days from the start of the culture. If the culture continued without the food suspension becoming highly contaminated by bacteria, they might be able to grow well even at 32°C.
