Development of Mass Seed Production Techniques for Green Snail, Turbo marmoratus in Okinawan Water

Abstract

The green snail, Turbo marmoratus is the largest species of the turbinid gastropods and is found in the coral reef areas. In recent years, stocks of this species have substantially been declining in the Ryukyu Islands. The method for multiplication of the present species i. e., development of mass seed production techniques, was considered for artificial enhancement of its resources. Egg collection of the green snail was possible between mid-June and early September in Okinawa Island, southern Japan. Exposing the animals to ultraviolet treated seawater after packing the individuals in small tanks was effective for spawning induction. Veliger larvae were kept without food in the incubators with running seawater until they developed into the early creeping stage in 2 to 3 days. By using sessile diatom as food, the juveniles were reared from the early creeping stage to the young juveniles of ca. 3-4 mm in mean shell diameter. Annual production of the seed shells numbered 390 and 880 × 10³ individuals in 1989 and 1990, respectively. The mass seed production techniques for commercial trochus, Trochus niloticus and silver mouth turban, Turbo argyrostoma can be applied to green snail with little modification.