The snow expected later today could doom fish on some northwestern Iowa lakes where water levels are extremely low. Don Herrig, a fisheries technician at the Iowa Department of Natural Resources, says lakes that are iced-over could be covered by snow, which will keep out the sun.When the sun can’t get through the ice to underwater plants, the plants can’t produce their own oxygen and use up the oxygen in the water, which the fish need to survive.Herrig works out of the D-N-R’s regional office in the town of Lake View beside Black Hawk Lake in Sac County. He says the water levels at Black Hawk and North Twin Lakes are 25 inches below normal.Other lakes have still-lower water levels, like Storm Lake, which is 45 inches lower than normal. Herrig blames the lack of rain during the summer and fall in western Iowa. He hopes the winter ahead will not bring a lot of snow cover or there will be far fewer fish in the spring.