Never caught a Steelhead. They are said to be the Holy Grail of fishing, the weight of salmon in some cases with the fight of a Rainbow trout. Here in the SF Bay Area, near a city named Walnut Creek, one can fish for salmon in that creek in January, as it is no doubt almost dry by now. Unbelievable, as it's muddy and has garbage and shopping carts in it. Salmon come up stream til stopped by a dam/spillway. The fish are either all beat up with flesh hanging off or brilliant in color or somewhere in between. I hooked a big one that I never saw, even when it was near my feet. He ran and broke the line. Saw a kid walking away holding one that reached his hip. Strange, beautiful phenomenon in the midst of a crowded urban area, though I haven't been back in a few years to see if it still happens.
Some fly rods do work on close-to-bottom fish. One uses a sinking or sink tip line, and flies that resemble early stage insects, and you watch for irregular movement of the line.
Just about every river fish in Alaska heads for the sea before the rivers freeze over. That includes the Arctic Char and Grayling. Steelheads remain out at sea for 2 or 3 years before returning to spawn. We had a number of years when it was only catch and release because some POS decided to illegally dump a bunch of northern pike into a lake and they got into the river and ate all the trout fry. Northern Pike is an invasive species in Alaska. Thankfully, things have returned back to normal and we can once again keep our Steelhead.
Salmon stop eating, begin to mutate, and start dying the instant they hit freshwater. I check the salmon I catch for sea lice. If the sea lice are still alive then it has not been in freshwater for more than three days. I try to fish close to estuaries to ensure my salmon are as fresh as possible. If they look all mutated and beat up, with flesh hanging off them, then they probably have been in freshwater for a week, maybe longer.
Since salmon stop eating when they hit freshwater, there is a trick to catching them. You bait them with salmon roe. They instinctively try to bury the floating blob of salmon roe into the mud or gravel on the river bottom. It is during that brief period when they suck the roe into their mouth, and before they spit it out again on the river bottom, that you have to set your hook. It takes a little practice to figure out the correct feel.
The Kenai River is the most popular river in Alaska for world class salmon. Five foot long 80-pound King salmon are not uncommon. Because it is so popular with the tourists, I fish the Ninilchik River closer to Homer. The Kings are only 20 to 30 pounds, but they are much easier to catch. Silvers are what I catch the most, but they don't start running until the end of June. Reds (Sockeye) are what I prefer because they are the best tasting, and they are the smallest of the five species of Pacific salmon weigh in between 6 and 8 pounds.
I'm planning on catching 250+ pounds of salmon by the end of July. Caribou season begins in August, so I want to have my salmon fishing finished and the salmon smoked by then.
Since halibut tend to be in 400+ foot deep waters, I seriously doubt even a weighted line would help. You need some serious weight to get it that deep rapidly.
