Fecundity: A female may have 750,000 to 8 million eggs per spawn, and can spawn two to three times in a year.

Longevity: Typical lifespan is about 3 years. Maximum life span may be 5 to 8 years.

Spawning season: May through September

Spawning area: Spawning rarely occurs in Maryland waters and is limited between the mouth of the Potomac River and Wolf Trap Light where salinities are 15-20 parts per thousand. Most spawning takes place in the lower Bay and the mouths of the Bay's southern rivers.

Transport: Larvae are transported from the lower Bay to the continental shelf, site of most larval development.

Zoeal Development: Development of zoeae generally occurs from the southern end of the Bay to 40 miles out in the coastal ocean. The highest rate of growth and survival occur at salinities of 26 to 33 parts per thousand and temperatures of 66 to 84 degrees. Larvae remain on the continental shelf for 30-45 days, going through seven or eight developmental stages. Once transformed into the post larval, or megalopa, stage, they reinvade the Bay aided primarily by wind and tides. During transport into the Bay, megalopae undergo physiological changes which prepare them for the metamorphic molt into the first juvenile stage. Settlement in the Bay usually occurs between July and mid-November.

Early juvenile stages: Post larvae crabs settle in the lower Bay and use beds of submerged aquatic vegetation. Large juveniles migrate out of the grassbeds and are found in greatest abundance upriver, in lower Bay tributaries. Eventually, they begin appearing in Maryland waters. Migration to the upper Bay and tributaries may begin as early as September through November; late migration begins the next spring. Large males generally occupy the upper reaches of tributaries and the Bay while females remain in higher salinity regions of the lower Bay and its tributaries.

Adults and Reproduction: Blue crabs mature at about 12 to 18 months of age. Mating occurs from May through September in lower and mid-Bay habitats where salinity preferences for males and females overlap. Females migrate to the higher salinities of the lower Bay where they develop an orange, external egg mass.

Chesapeake Bay Blue Crab
Fishery Management Plan