Wecome to the board. I used to be stationed in Jax but don't remember that river. If it is stained (cypruss trees) like ours is up here, you will catch very few crappie with just a jig.
Try different colors with a minnow until you find what they want. And even then, that can change with passing clouds. Check with the people at the Fla forum. I'm sure they would be glad to help. Catch a bunch!