Crabs grow by shedding their old shell, a process called molting. During their first two years, crabs molt several times. Just after molting, crabs are very watery and soft and their shell is easily punctured. They dig into the sand and stay there for several days while their shell starts to harden. Approximately two to three months are required for an adult crab to completely harden and fill with meat.
Most males molt during the summer and fall months, but the time can vary greatly by year and area.
They will mate with several females. Mating takes place between a hard male and a soft, smaller female immediately after the female molts. A female produces up to 2.5 million eggs. Most crabs caught in the fishery are four years of age and have been sexually mature for one to two years. They range from central California to the Gulf of Alaska, and have long been part of the Northwest's seafood heritage.