Way back when...
When I first started fishing the POC area, the "major deep" part of Pass Cavallo was from the gulf to the inside of what is now Sunday beach. The land to the left was actually an island called "Middle Ground". It was that way for many, many years.
I have always felt that if even a tiny opening was made, the Gulf herself would keep it open and widen/deepen it. Perhaps if we all got some shovels...LOL!
Some of the most awesome surf fishing I ever did was wading off Middle Ground. We would park the boat on the "back" side and throw Bingos off the "front" and "side" into the pass.
I can remember - before conservation and knowing what we know now - filling 15' stringers from hook to float with 2-4 lb. trout. 100-trout per man (boy) days. Tarpon were common on these outings (at least hooking 'em) and I've seen kingfish, huge sharks, monster jacks, sawfish, ling and even a huge grouper (might have been a jewfish) caught while wading off Middle Ground. Once we had a 14-15' sawfish swim right past us in about 2' of water. This was in the late sixties.
Fish Pond was a major staging area for trout moving in/out of the surf and the tarpon used to make regular visits in their and most late summer mornings you would see some rollers along the front beach from the pass as the tarpon moved towards Saluria.
Ahhhh...the good ol' days..