In Newfoundland, the ice fishing season ends on April 15th. If you are reading this, there is a 50% chance that you still have time to get-in-on-the-action before summer comes back and you’ll have to fish from dry-land again like a mere mortal.
Ice fishing is, legally speaking, the exact same as trout-angling in the summer: you may catch 12 trout per day, each of which must be longer than 8 inches in order to be kept. Holes are drilled into the frozen surface of the lake/pond with a large drill called an Auger.
Ice Fishing rods are about 2.5-4 feet long and don’t have a release so you cannot cast them – you simply drop a line with whatever bait you want and wait – jigging occasionally. You may have up to three rods on the go simultaneously. I recommend attaching a bell to each rod so you can tell if you get a nibble.
It is generally only safe to walk on ice after it is 4-inches thick, ~7 inches for snowmobiles. When in doubt, look online: the red cross has a great procedure to determine the safety of pond ice.
Fish blood (in northern species) contains a protein that acts like an antifreeze – it actually works much better than commercial antifreeze, as is does not bond with the water itself, rather its presence breaks up the water’s flow pattern, so that it becomes unable to crystallize properly. This has lead Volkswagen to study several arctic species, looking to develop more cold-resistant engine fluids.
Further, fish are cold-blooded. This means not only that they don’t produce their own body heat, but it also means their internal processes do not require a steady temperature to sustain themselves like mammals’ bodies do. However, due to this drop, their bodies become literally slower. This slower metabolism is key: fish must conserve not only calories but also oxygen levels over the course of the winter.
The ‘lid’ formed by the lake reduces aquatic algae’s ability to photosynthesize, causing much to die off. This creates both a decrease food supply and blooms of decomposing activity (which takes up even more oxygen and can effectively cause fish to “drown”).
Any major disturbance in this balance can really mess up a lake and create “dead-zones” where nothing lives, as is the case in portions of the Great Lakes.
Seasonally, air temperatures drop much quicker than water or land temperatures. Colder air withdraws energy from the water at its point of contact, the surface, which causes the first layer of freezing. Because of water’s (literally life-enabling) chemical structure, instead of thickening when cooled, water will freeze into a crystal structure (ice, duh) which makes it less dense than water. This causes ice not to sink to the bottom of water.
This lid of floating ice acts as an insulating barrier against the winter air and in most cases stops the top ice from forming its way down to the bottom of deeper bodies. Were this not the case, the fish would be killed, and ice-fishing subsequently impossible, so, hurray for that!