Ice Fishing walleye……Nighttime,,,,,

I have a question on ice fishing river walleye……..The river I fish has a pretty good current to it and is fairly murky water……..I’ve never tried night ice fishing there yet but the locals tell me they don’t hit at night………I’m usually there a hour before sunrise and have never marked a fish in the dark………The area I fish is a big 13.5′ flat which makes up most of the river……..The shoreline of the river drops off pretty fast to that 13.5’depth……Would those walleye be tight to the shoreline at night there’s no real shelves for them to sit on it’s 0′ to 13.5’about 25′ off shore………I hope this makes sense……JHM