Growth of the Bryozoan Bugula neritina in the Sea at Various Water Temperatures

Abstract

The response of Bugula neritina in the early growth stage of a colony to the environmental water temperature was studied.
The larvae attached on slide glasses were immersed 1 m below the surface in the sea at five experimental sites. In the colonial growth, the increase of the zooid number had a parallel relation with the increase of branch number and of the dry and wet weights. The growth speed of a colony could be expressed as the function of the number of zooid (N):dN/dt=rN(t, day: r, intrinsic rate of natural increase of zooid).
The experiment on colonial growth conducted in four seasons at various temperatures revealed that the lowest temperature for survival was about 9°C, the lower limit of temperature for the exponential growth was about 13°C. The relation between the intrinsic rate (r) and water temperature (T) for a temperature range from 13 to 28°C could be represented by the following equation: logr=0.04T-1.3. B. neritina was supposed to tolerate without any abnormal symptom even a high temperature of 30°C.