I too have noticed they like to hang out near the swallow poop. I think the poop attracts baitfish.
Dont tie up to the piling right off. get you each an 8 foot pole, and tie on a triple threat. )3 different jigs tipped with either crappie nibbles or minnows spaced abt 10 inches to a foot apart.(heaviest jig on the bottom). ease up to the piling, starting in around 8 foot of water, drop to the bottom, wait a few sec, reel two cranks, wait a fdew secs, if no bite, move to the next set of pilings down that are deeper. you can make quick work of locating the fish this way. If your buddy can fish one side of the piling while you fish the other, its more effective. dont tie up to a piling unless you establish a pattern .. around 5 fish. stick and move, until you find them. If its morning time or cloudy and overcast they may be up shallow. just cover the whole water column before you move.