1- Yeah, the pirates just collect into large groups and don't start as such. They seem to collect in little inlet sea areas where they get stuck. They may be weakened in the future.

2- There is a whole thread going on this right now. Basically, each EB 'ship' equals a fleet. The number in the corner is the number of ships, not people. And whereas there might be ships on the Caspian, it would be inappropriate to have large fleets there.