Ice fishing the Gem State
by Charlie Powell

Soon it will be ice fishing time, and understanding how small lakes freeze and what happens under the ice can help Idaho's ice fishing anglers be more successful.

As water in a small lake cools, to near 39.2 degrees Fahrenheit, it becomes more dense and settles to the bottom. But we all know that ice floats and is less dense than water, even though it is at 32 degrees. So imagine a layer cake of sorts, ice at the top at 32 degrees with water immediately underneath at about the same temperature. As we progress down, the water is warmer, up to 39 degrees, but heavier.

Water also has a high heat capacity. For 32 degree water to become 32 degree ice, it must give off about 59 times as much heat as an equal quantity of water would by just losing one degree. Consequently, it is easy to understand why only the shallowest lakes ever freeze solid except in the Arctic regions.

What exists then under the ice is a unique, seasonal environment. Unless there is a heavy snow cover over the ice, photosynthesis still continues, producing oxygen.

Oxygen dissolves in water to a certain extent. Differences in pressure, temperature, and concentration all affect the rate at which oxygen, or any other gas, dissolves in water.

Trout need about 10 parts per million, oxygen to water, to live in cold water. Most warmwater species can get down to about 5 parts per million comfortably. Some species like carp, goldfish, and catfish can survive even greater oxygen starvation for varying periods of time.

When a lake freezes over, atmospheric oxygen cannot be mixed into the water by wind action. Oxygen produced in the lake from photosynthesis is limited to certain areas only. In the unlighted depths of a lake, natural decay going on in the bottom layer can use up more oxygen than is produced. Fish will stay out of that zone and so will successful anglers.

So what happens if there is a lot of organic matter decaying rapidly on the bottom? The oxygen-poor layer begins to thicken toward the surface. The shallower the lake, the more organic matter there is to decay usually. The deeper the snow cover on the ice, the more severe this can become. With sufficient oxygen depletion, winterkill of up to the entire fish population can occur unless the ice melts off or humans intervene. Some may recall the extraordinary winterkill experienced at Henry's Lake in eastern Idaho in 1990.

Trout under ice are somewhat easy to catch on many different kinds of bait. Cheap favorites include corn, cheese, and worms. Dried or pickled maggots work well, too. Some ice anglers will stoop to chumming a hole to attract more fish, rather than moving and drilling another. It's easy, cut the top off a can of niblets or dice a brick of processed cheese, center it over the hole, and bombs away. It's also illegal and about the stupidest thing you can do. You're just adding to the organic load to decay on the bottom using up more oxygen. With the right conditions, you can be responsible for a massive winterkill.

Tiny spoons or jigs available in bait shops throughout the state tipped with a bit of the favorite baits and jigged slowly will usually do the trick for hooking most trout and yellow perch through the ice. In some lakes, white crappie can be found. The nice thing about crappies is that once you locate them, it's not uncommon to catch a limit without drilling another hole.

In Southwestern Idaho there are many opportunities for ice fishing. One of the all time favorites is Cascade Lake. Both rainbow and yellow perch are targeted here, and anglers often come home with limits of both speicies. Another Southcentral favorite is Magic Reservoir, where you can also catch a multitude of species including rainbow trout, perch and brown trout. For the most up to date information on fishing these and other local impoundments, give the folks at Howard's Tackle Shoppe in Nampa a call at (208) 465-0946.

In Coeur d'Alene Lake and the chain lakes nearby, double digit Northern pike are taken each winter using whole dead fish. For the most up to date information on catching pike in northern Idaho, give the folks at the Fins & Feathers Tackle Shop in Coeur d'Alene a call at (208) 667-9304.

The new generation of ice fishing rods are certainly nice, but the tip section of a slow to moderate action spinning rod pushed into a homemade dowel handle and a taped on ultralight spinning reel works just as good. Monofilaments of four to six pound test formulated to remain limp in icy conditions are ideal for everything but the pike.

To get on the ice safely, remember four inches is a minimum. Hand ice drills are better than axes, spuds, tire irons, screwdrivers, or any other device for making holes that are not only safe but effective. Afterall, when you leave, someone else should have to worry about stepping in your ineptitude. For the technically inclined, a portable fish finder used right on the ice can prevent drilling too many holes.

For yourself, consider synthetic long underwear to wick away bone-chilling moisture. Layer over your longjohns with wool or another layer of synthetics, like polypropylene garments. On top, wear a knit hat with ear protection. On your feet, insulated pac boots are the norm. Finally, a good pair of insulated bib overalls or coveralls will go a long way here because ice houses are not commonly used in the West.

A child's sled to haul out the gear, a length of rope, a 5-gallon pickle bucket to sit on, an ice strainer for the hole, and some food and a warm beverage can round out a great low cost way to stave off another bout of cabin fever in the Gem State.

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Copyright 2005 by Spring Creek Communications