I can't answer for the SE US, but Venice isn't that different from other parts of Florida. There are fossils (and fossil clubs finding fossils) all over the state. People find fossils in quarries, in construction sites, in rivers and streams, etc. All you have to do to find fossils in Florida is dig and look or look where someone (or something) else is digging. Rivers and streams dig all the time.
Sea level has been much higher and much lower than it is today. There were times when Florida was completely underwater. There were other times when Florida was much larger than it is today extending much farther out into the Gulf. If we find an area, like off shore Venice, that was the site of an ancient river, we are likely to find fossils while diving.