The only thing for sure is that it will be different. Hard to say if better or worse.
I will miss the old structure regardless. Even as it was it required annual study to have it in the hip pocket for guiding. Yet much of it retained the same character year to year as I am sure others will agree.
With a cut midway on Chatham Bar (the official name of south beach or so I read) several annual routines that I rely will change dramatically:
1) migratory paths - no details available
2) flood tide response - many changes there for sure, the fish will be in different places and move to different places on tidal changes
3) summer behavior - cool ocean infusion almost 1 hour earlier - more like bayside behavior around that zone I would wager. As Keith mentioned, probably would get visits from the oceanside hordes as well. I just hope the boats aren't overwhelming if it really opens up.
4) fall bunker behavior - more likely to stream through the refuge than go around, which bodes very well for our fall fishing
5) hardtail behavior - likely to have them more prevalent inside and up to Chatham light than usual, maybe thick in PB like years past. This depends on how the west side is affected from all this, and if JimS theory is correct, etc.
At least in this zone there will undoubtedly be a more prevalent mixing of sound / ocean conditions where this peninsula has formed a distinct boundary for many species and their habitats. The behavior of fish inside has been distinctly different than on the outside. Despite being so close together, they were separated by two diverse environments.
If the southway closes it will create a massive expanse of flats to the other side of the break; K & J bouy flats, reaching down to join with the north end South Monomoy flats, then out to the west side.
Who knows what it will do to North Monomoy but my guess is a deepening of the crib. In fact the middle crib's depths seem to be formed by a more violent past.
In any case, it will be a lot of fun to explore and nature will level the playing field for most of us. We will all need to re-learn everything if these things go down.