It's been a while and due to one reason or another I haven't been out much.
I went for a quick paddle a month or so ago with my daughter under the walk bridge and out past the board walking area, super clear and I noticed a couple of big holes (is this where the hole you mentioned is?). Even spotted a large flathead, unfortunately no fishing gear. I though I might try it out with my daughter as it's pretty quiet, she is only 4 so is small enough to fit on the kayak with me.