Typically for steelhead, monofilament and fluorocarbon line are used, regardless of the region you are fishing. Braided line is not as popular for steelhead fishing unless you are throwing spoons or spinners.
For most anglers, monofilament is the popular choice for a main line year-round. A lot of anglers will choose a brightly colored monofilament and attach a fluorocarbon leader. Fluorocarbon can be used as a main line in warmer temperatures, but it does not have a lot of stretch to it, which can cause the line to bunch up and bind. Braided line can also be utilized in warmer weather and water, but is not ideally used as a main line. Fluorocarbon tends to become brittle and frail as temperatures decrease and braided line starts to stiffen when it gets cold. Both of these reactions are less than ideal when targeting steelhead.
Selecting the correct type of line is extremely important. If you have a strong, fighting fish on a line with little-to-no stretch, hooks can be straightened or knots can break. If the line is too light for the fish, the line will snap and a trophy fish could be lost. This doesn’t mean you should pick a heavier line to be safe. Using a line that is too heavy can allow the fish to see the line and your productivity can drop drastically. Using the wrong line can throw off a whole day of fishing.
The most critical part of choosing line for steelhead, especially in the Great Lakes region, is making sure you are using the lightest leader possible. This will allow for a more subtle presentation in the water, creating less of an opportunity to spook the steelhead (or any other fish). The color of the line is also extremely important. Matching your monofilament leader to the water color will allow for an almost invisible line. In the Great Lakes region, a clear monofilament is typical for leader material, but don’t hesitate to fish with brown monofilament if the water is looking muddy and dirty. Green monofilament can also work well in green tinted waters. If you’re using a fluorocarbon leader, the color doesn’t matter as much, but most anglers tend to go for a natural or clear color.