Hello Paul,
I don't know for sure what they use in Isla Morada for bones but there are some flies which are generally used and those would be: shrimp and crab imitations like Crazy Charlies and Gotchas and Del Brown's Yarn Merkin. When I planned our trip to Florida a couple of months aga, I tied some of the foam crab imitations and the yarn crab imitations(Del Brown's merkin), and a few the shrimp patterns. When I stopped at the local fly shop, I found that the guides often rely on their own patterns. If you arrange for a guide through a fly shop, the guide will usually provide the flies or have them available for purchase as will the flyshop. Anyway, I used Mustad hooks # 34011 & #34007 stainaless steel in sizes #2, 4, 6,and 8 for both the shrimp and crab patterns.

I found my patterns at:

http://www.branhamssaltwaterflytying.co ... /page1.asp

There is lots of good stuff there so have fun!