I am using nibbles and that does make sense. However, I don't sense that that's what's happening. The bites around pilings are usually pretty quick, sometimes on the fall but usually when the jig gets to their preferred depth for the day. Some days I do catch them in that calm water down current but I'd say they're upcurrent 7 out of 10 times.
I used to do a lot of tuna fishing and the same thing usually occurs around oil rigs. Upcurrent was always the ticket.