Inducement of shell opening of Amusium japonicum by MgCl2 injection into the adductor muscle

The objective of this study is the establishment of a method for inducing t he shell opening of Amusium japonicum by injecting a MgCl2 solution into th e adductor muscle. The solutions used were made with natural seawater and 0 .2 M, 0.4 M, and 0.6 M MgCl2 solutions in the following quantities, 1 mi, 3 mi, and 5 mi, were used, respectively. After the injection, their adductor muscle relaxed and opened. The opening angle of the shells varied from nin e to 12 degrees. The molluscs stayed opened even after mechanical stimulati on with the following MgCl2 solutions only: 0.4 M (5 mi), 0.6 M (3 ml), and 0.6 M (5 mi). The molluscs required 26 min 49 s, 40 min 29 s, and 39 min 3 0 a, respectively, to recover from the effects of the injections. The exper imental molluscs showed the same conditions as a control individual 24 hour s after the injections. In this study, we obtained the result that the most effective method was to inject 5 ml of the 0.4 M MgCl2 solution into the a dductor muscle, because it was necessary for us to resume fast shell moveme nt. The injection of MgCl2 solution into the adductor muscle has proved to be a good method to induce the shell opening of a bivalve species like Amus ium japonicum.