I did my research project under Dr.Guo Junyao of Ecosystems Studies and Aquaculture Laboratory, School of Biological Sciences at the National University of Singapore.

Dr.Guo is a research scientist and he is interested in all aspects of the Eriocheir sinensis crab, also known as the Hairy Crab. Currently, research on the reproduction, rearing techniques, feed and the physiology of the crab are extensively studied.

The Chinese euryhaline water crab Eriocheir sinensis is of ecological importance and enormous aquacultural potential. It is of high demand due to its unique taste. However, due to environmental changes and high demand, the wild stock has declined rapidly over the last 15 years.

The hairy crab grow up in freshwater inland and migrate to estuaries to spawn. The hatching process usually require more than 70 days to spawn. In open space breeding grounds, there are temperature and salinity fluctuations.

Currently, the technology of in vitro artificial incubation and hatching of the hairy crab is not available. This technology would be of high commercial value because it will provide a tool for controlling the environment and make the study of embryonic development more feasible. Many eggs could be incubated in a smaller volume of water at controlled environmental conditions. Thus, we can maximize the yield of the crabs.

Previous artificial incubations conducted showed that the crab embryos were very prone to fungi infections. In natural conditions, the female crab preens and aerate her embryos to protect fungi from settling on them. Thus, a good substitute for the mother crab must be able to provide sufficient aeration for the embryos yet protect them from fungi infections.

The main objectives of this experiment are :

1. To determine a suitable anti-fungi agent which will curb fungi infection

2. To devise an incubation system which will substitute the mother crab

Results :

The best anti-fungi agent which could curb fungi infection is methylene blue used at a concentration range varying from 20 ppm to 80 ppm. 20 ppm methylene blue concentration is more suitable as a higher range is feared to exceed the embryos' toxicity limit.

The incubation system should provide sufficient aeration and proper water circulation to prevent fungi infection.

Conclusions

The crab embryos are best incubated at 20 ppt salinity and temperature of 19 to 20 degrees celsius.

Crab embryos are best to be obtained when they are late gastrula stages for the incubation process.