Bay Bulls VS. Beach Bulls

As I have looked through numerous fishing reports on this site, I have noticed a trend in the differences in the physical appearance of bull sharks caught in bays, and those caught oceanside. Several very large bay-caught specimens I have seen here (like the large one caught behind the seaquarium) seem to have a more deeply curved dorsal. That is, they seem to have a severe crescent shape. The same also goes for the tail (caudal) fins; they both have a fatter and deeply curved shape, whereas beach-caught bulls seem to have smoother, straighter fins. Their dorsals are much more triangular, and the tails point upward as opposed to curving back and pointing on a parallel plane with the shark's body as in the bay specimens. Look at the two photos of large, mature bulls below:

Bay-caught fish. Notice all of the fins seem to have the deep, exaggerated curve to them; the dorsal, second dorsal, anal, and the bottom of the tail.

Beach-caught fish. Seems to have straighter, "typical" fins.

This is just speculation, but I believe this difference in curvature comes from certain bulls becoming residential bay fish. Certain individuals rarely leave the bays, and so they develop this new fin structure as a result, maybe to decrease how much their fins stick out and make them more compact for shallow water, I don't know. The ocean-going fish then are more filled out and developed for maximum control in an environment where they can freely move and need the control that normal fins give. I'm sure all bulls venture into the bays at some point, so there are some "ocean finned" specimens caught in the bay, but it never seems to happen the other way around. What do you guys think? Has anyone else noticed this difference?