How many shine sprites do you need to get to bowser on Mario sunshine

You do not need a certain number of Shine Sprites before you get to Bowser. Instead, you need to beat every Mission 7 (the Shadow Mario mission) in each of the seven worlds to be able to access the area where Bowser hides. So, without getting any Shines from Delphino Plaza, Blue Coins or the Hidden Shines in worlds, the bare minimum number of shines you can get before taking on Bowser is 49.