Studies on the Aquiculture of Sulculus diversicolor diversicolor-I

Development and Growth

Abstract

The writers succeded to get the fertilized eggs “fuku-tokobushi” Sulculus diversicolor diversicolor (REEVE) in August, 1967 and investigated their development and growth for 365 days after fertilization.
The results obtained are summarized as follows:
1) Spawning was artificially induced by the stimulation of fluctuations of water temperature, within the range 21.8-28.0°C and the fertilized eggs are taken at the time of lower temperature.
2) The eggs are spherical in shape and the average diameter is 0.197mm (0.1846-0.2154) including egg membrane, and that of yolk is 0.168mm (0.1539-0.1846) in fertilized condition.
3) There observed some differences in the development between Sulculus diversicolor diversicolor and S. diversicolor agvatilis as shown in Table 1.
4) The veliger larvae settle to the bottom from 66 hours to 170 hours after fertilization.
5) The growth curve of young shell during 330 days is shown in Fig. 3.
6) It is presumed that Sulculus will reach the legal size (shell length 45mm) at 18 months after fertilization.