Honestly, this is a very small portion of the gulls that were on Pace Point, much less the general area. A young Bald Eagle was responsible for this mass flush.
I would put a pretty conservative estimate of 30,000-40,000 gulls in the general Paris Landing/Pace Point vicinity. I have seen some very impressive gull concentrations here before, as well as Reelfoot, etc; but I honestly believe today may be the most I've seen, period.