Aspects of the behavior of ovigerous Dungeness crabs (Cancer magister) were studied in Fritz Cove, Alaska. To test fidelity and homing ability of crabs to their brooding site, we ultrasonically tagged eight ovigerous crabs and transplanted them 1.4 km from their brooding site. Eight ultrasonically tagged control crabs were returned to the brooding site. Crab movements were subsequently monitored weekly from late February to October to determine activity patterns and seasonal shifts in depth distribution and habitat use. Seven females transplanted away from the brooding site homed back to that site within 13 to 20 d. Ovigerous female crabs showed fidelity to the head of the cove and ranged a maximum of 3.4 km. Crabs had distinct seasonal patterns of depth distribution, habitat use, and activity which were related to reproductive status. The general pattern for female crabs was: (1) a relatively inactive period during winter and early spring at depths greater than −16 m; ovigerous crabs were typically buried during this period in a dense aggregation; (2) an abrupt movement into shallow water (less than −10 m) during mid-April and residence there until late June; this movement was coincident with the spring phytoplankton bloom and initiation of larval hatching; and (3) increased activity beginning in July with movement back to deeper water presumably to forage. Females that molted prior to oviposition did so between late May and September. Females occupied depths between 1.6 and −107.3 m. Home ranges were small (< 4% of the total cove habitat) and varied with crab size; smaller crabs had larger home ranges. Ovigerous females brooded embryos in a small, discrete area of unconsolidated, homogeneous, fine sand. These sediments were also highly permeable. Annual use of the main brooding area was documented for a 12-year period and emphasizes the importance of this essential habitat.