Bridge question

I've been on a good bite from daylight til 10 ish for the last couple of weeks. I have gone a couple of times a couple hrs before daylight and put the green lights on a haven't gotten a bite yet. As soon as it gets light enough to see they start bitin. I just can't figure why they won't hit at while it's dark?

They will hit when it's dark out, but I find them more aggressive once it gets light too.

try fishing 3 ft deep if your jigging. lots of nights they aren't deep at all regardless of how deep the water is.