Sir Intimidator is correct; about 3/4th of our cover is mostly for use as nursery purposes but the logic still stands that #1: ANY cover beats none and #2: if it allows juvenile fish to get bigger it`s still going to attract some predators occasionally... a gentleman named Saugeye Marc posted when we were 1st starting the projects saying that while 1st ice fishing each season that he tries to find the sets of cover that still are covered by the moss and algae and will patiently await a school of shad to arrive and start devouring it, pooping and shedding their scales inside the sets. In the mean while he would watch on his Aqua-View camera with low light capability as the predators would start to gather just outside...soon the school of shad would almost completely strip all the algae off the cover. They are then faced with a choice: run for it or stay and starve...he says he has done VERY well under such circumstances and is bummed out because by mid winter all the sets have already been stripped of their algae...