The pilots don't depart until the ship is at the sea buoy, clear of the ship channel. Pilots are required in local waters where knowledge of wind and currents, depths, turns, hazards to navigation and etc. exist. Some ships, although it's rare, can forego pilots, but one of the officers on board must be certified to navigate the local waters.I thought that, by the time the ship reached the channel near the bridge, the Pilots would have already turned over to the crew, and departed.
The pilots unions are very insular, someone almost literally has to die before they admit a new member and often the new member is the son or grandson of the deceased member.
The senior pilots can make $300-$500,000 a year especially in the busy ports.
Towboat captains on the Mississippi can easily bring in $250,000, some of them more.