As waters warm in the summer months, a northward migration extends into the Gulf of Alaska, reversing southward during winter. The migrations may be reproductive in nature and follow the advance and retreat of a transition zone between major ocean currents. As blue sharks mature, there is considerable sexual segregation in populations, with females more abundant at higher latitudes than males. Unisexual schools form in the summer and autumn, and assembly of mixed schools takes place in the winter. Most blue sharks that migrate to Monterey Bay, CA during the late summer and early fall are immature females.
Mature adults are uncommon in coastal waters.
There are no local or Pacific-wide estimates of stocks or abundance. In California, blue sharks were captured during the development of the drift gill net fishery for swordfish and thresher shark. However, blue shark must be bled, dressed, and cooled down quickly, otherwise the urea within the tissue begins to change to ammonia rendering the meat unpalatable. Therefore, the meat quality of blue shark harvested by gill nets was poor. Meat quality of catches by longline gear has been high enough where some markets have been developed.