Unlike the Anhinga who spear their food with their sharp straight beak the Double-Crested Cormorant hooks it’s prey.
Juveniles have pale white/brown chests with patches of darker brown and the adults are dark brown/black. These birds are powerful swimmers.
By the sizes of these, I am assuming a couple of years old. I occasionally drive around Bayport, and I am surprised that I didn’t see them when they were younger, or maybe they were breed somewhere else and moved to this location.
Recently in Tampa, Lettuce Lake Park has a great boardwalk for nature photographers and while observing the Black-crowned Night Heron, I learned something.
This is just an observation guess… notice what the bird does while its beak is in the water. My guess is that by gently snapping into the water creates a vibration which will bring fish or other species from underwater to the surface.