Fishery Biology ofCharybdis natator Among the total number of 473C. natator , the biggest carapace width of female is 10.9cm, while male is 13.3cm. The monthly sex ratio is between 0.18-0.67, with an annual average of 0.41. Ovigerous crabs were unfound only in November and December; moreover, February to May and July are the peak periods. The average of batch fecundity is between 385,000-950,000.Fishery Biology ofPortunus sanguinolentus Among the total number of 989P. sanguinolentus , the biggest carapace width of female is 18.2cm, while male is 18.7cm. The monthly sex ratio is between 0.46-0.81, with an annual average of 0.67. Productive activity happens all year round; moreover, February to April and July to August are the peak periods. The average of batch fecundity is between 760,160±520,085.Fishery Biology ofPortunus pelagicus Among the total number of 242P. pelagicus , the monthly sex ratio is between 0.31-0.80, with an annual average of 0.58.Productive activity happens in every season; moreover, February to April and July to September are the peak periods. The smallest carapace width of mature females with GSI over two is 11.3cm. The average of batch fecundity is between 1,112,455±529,925. The current crab catching regulation forbid to catch ovigerous crabs during August 16 thto November 15 thevery year; however, it’s not enough to protect the ovigerous crabs of these three kinds of commercial crab. We suggest that the prohibition against catching ovigerous crabs should be extended towhole year round. Furthermore, theprohibition size ofC.natatorshould be extended to 8cm,P. sanguinolentusshould be extended to 10cm, andP. pelagicus s hould be extended to 12cm at least.