The male carries the female around before her moult and may continue to protect her for several days after copulation. The male's behavior, as well as being of considerable survival value to the vulnerable female, serves to guard his genetic investment against the death of the female and displacement by other males. Subsequently, the female extrudes many thousands of fertilized eggs onto the swimmerets under her abdomen. The eggs usually hatch during the warmer months of the year and free-swimming larvae are released. The larvae may spend from one to several months in the plankton and moult through a number of stages before settling down on the sea bed and moulting to the first crab stage.
Ocean currents can transport larvae considerable distances from their hatching place.
The massive mortalities that occur during the larval stages tend to be compensated for by the vast numbers of larvae produced. Since the early 1960's, fisheries biologists from provincial and federal governments, as well as from universities, have been carrying out research into crab. The work has been conducted for a variety of purposes, to estimate stock abundance and size composition, growth rate, reproductive pattern, movement, and exploitation rate. However, all the work has a common aim in providing an accurate picture of the crab resources so that they can be properly managed. Traps, beam trawls and towed underwater camera sledges are used from government research vessels and commercial vessels under charter to assess crab densities on the bottom.