Charks at the jetties in summer?

[MathGeek]

My boys really got a thrill by catching a 30" shark at the jetties (Calcasieu Pass) on the last trip. Since we've fished that area a lot from Dec-Jun with only one shark, I've kinda figured that sharks tended to show up later in the summer and the early fall. Is this right? Is there a particular approach that one might use to get the kids on a shark or two more regularly at the jetties or nearby at the beach?

I suppose we could try chumming, but when there are other anglers around, they might not appreciate it. Is the area affected by chum big enough that the sharks would bother anglers in other boats, or would it more be attracting the sharks that would trouble them over to our boat?