Profitable pirate ventures need to be built on rich trade routes so they have big, fat, juicy merchant ships to plunder and pirate.
What competing powers does your pirate area sit between?
What are those powers doing to patrol the waters and stop their trade ships from being plundered?
Whose the most famous pirate hunter in the area? What's their methods and what're they doing right now?
Whats the latest 'big haul' the pirates have pulled in? What were they rumoured to have found? Similarly whose the last pirate to have been caught or killed? How?
This sounds like tonnes of fun, hope your players enjoy!