In The Mountain in the Sea by Ray Nayler there are fleets of fishing boats that are all controlled by AI to maximize the catch. Each boat also has it's own AI that can act somewhat independently, but they all communicate with the main corporate AI as well as with other boats in the vicinity. Initially the boats are all fully automated and have robots doing all the work, but in the ocean environment the robots tend to break down a lot due to corrosion. At some point the AI in charge of the fleet figures out that it can use kidnapped humans in place of the robots. The humans are kidnapped and drugged so that they don't wake up until the ship is well out at sea. Even after that they're kept drugged to some extent so that they aren't inclined to escape. They're given just enough food to enable them to do their work and no more. When they become sick they're thrown overboard and new kidnappees replace them.

This is just one of the side plots of the book, I think it could've been the whole plot of a book.