Sea run cutthroat are not endangered.
Bull trout and dolly varden are definitely not endangered, and I believe they even had their threatened rating removed recently.
Steelhead are only threatened or endangered in certain systems - and those would be minimally present right now, and are rarely targeted by anglers.
Go ahead and fish for those 3 if you want. If you're tossing a large glob of roe on a chinook sized bar rod - I would ticket you as a CO or DFO officer, because it is not justifiable. If you have a 4-8 pound rod in the holder and 6 pound test on for the bulls and cutthroat, then fine. Chucking spoons and flies is the most selective way to fish for those fish anyway. I agree with Ralph that if you are really concerned about the well being of the trout and dollies, you wouldn't bottom fish bait.
Sturgeon are listed as threatened, but the fishery that takes place has been shown to not cause a negative impact on the population. The population of sturgeon in the lower fraser has increased in the last few years, and are doing quite well. The tagging program that guides carry out is also a bonus and helps research take place on these fish. Boycotting that fishery is useless. I don't necessarily agree with catching the same old fish over and over, but it obviously hasn't caused significant damage and has led to positive things.
In the end... leave all the freaking fish alone right now. The water is hot, and numbers of particular fish are low. It's about time people understand that we don't need to be the ones to kill that last fish. Stop looking for loopholes and go do some different fisheries - it's a good way to expand your horizons. No one NEEDS to fish, and if we truly care, then everyone would stop their whining and would hang up the salmon rods for 1/3 of the poor return years (this year), and wait for the fall rains and plentiful hatchery runs to show up! It's really not a big deal in the end (and you'll forget about it soon enough), and maybe, just maybe, the fish will come back to fish-able numbers in the future rather than going extinct and you NEVER having that opportunity again.
This has probably been the most frustrating year I've ever witnessed on multiple forums and social media. Everyone wants their right to kill, even though there is nothing left. Everyone is arguing about that last slice of the pie that has disappeared from under their noses while they b**ched and moaned to each other about how it's theirs and how they have rights to it. People are willingly saying they will fish anyway and break the law because it's their right - with no regard to that one doe/fish they might accidentally catch, stress out and kill - which could produce 10's or hundreds of offspring. Every single fish does matter at this point - whether you believe that or not is your personal problem. Time to stop all this useless banter. It only gives all sport fisherman a bad name in the eyes of the general public (it's even giving me a bad taste in my mouth towards "rec" anglers). Stop killing the fish and go volunteer your fishing time to do some restoration work, stream fertilizations, brood capture, tagging programs, stream surveys in the fall.