on yellowfin, dont count on them being in less than 200 ft of water, Blackfin will be in closer around the Shrimp Boats, whith an occasional yellow in the mix, once yellowfin mature, they generally go off on their own to hunt then return to school during the night..
Some YT's see at night at floaters on flying fish and bonita. No many YT's around right now. Big strong gulf currents and large fresh water flows have changed patterns. Look for weedlines and fish for dolphin, kings and wahoo. If you find some shrimp boats - you will find a few blackfin.
BFT anywhere in 200ft of water behind shimp boats. I have not heard any reports with the exception of several excursions out of Port A and Freeport. You might look for the track that gives you access to deepwater quick out of GYB.