Artificial incubation of Japanese crayfish (Cambaroides japonicus) eggs by using a simple, easy method with a microplate

We developed a simple, easy method with a microplate to artificially incubate Japanese crayfish (Cambaroides japonicus) eggs for their cultivation. We prepared 6-, 12-, 24-, 48-, and 96-well microplates containing sterile water heated to 5, 10, 15, and 20°C. Fourteen experimental groups for each water temperature were prepared for each of different water volumes (0.125-10 ml) in each well. One embryonic egg was placed in each well. Experiments were also conducted with water collected from the lake where the eggs were harvested from and held at 15°C. In the microplates with sterile water, high proportions of eggs hatched (60-100%) at 15°C in all volumes of water, although the proportions of hatching were low (0-20%) at 5, 10, and 20°C. All eggs died in the experiments that used lake water. We conclude that the 96-well would be the most effective size to hatch crayfish eggs in, because of its convenience. This method using a microplate is simpler and easier compared with methods of previous studies to artificially incubate crayfish eggs, and therefore it might be useful to incubate eggs of other freshwater crayfish species.