Cipriano,
Here is the latest Bag and Size Limit info:
http://www.tpwd.state.tx.us/publications/annual/fish/limits_saltwater/Sharks : Atlantic sharpnose, Blacktip, Bonnethead Daily Bag limit is 1 fish.
Length Limits are: 24" Minimum — No limit on Maximum Size.
All other allowable species Length Limits are: 64" Minimum — No limit on Maximum size.
Special Regulation: the daily bag limit is 1 fish for all allowable shark species INCLUDING Atlantic sharpnose, blacktip, and bonnethead
Prohibited shark species: Atlantic angel, Basking Bigeye sand tiger, Bigeye sixgill, Bigeye thresher, Bignose, Caribbean reef, Caribbean sharpnose, Dusky, Galapagos, Longfin mako, Narrowtooth, Night, Sandbar, Sand tiger, Sevengill, Silky, Sixgill, Smalltail, Whale, and White.
I would just stick with Black Tip as a keeper.
They are good size and good eating.
You won't even see most of the prohibited sharks...
-gus