Those flies are trolled behind a downrigger. I don't think anyone uses them in the spring when the browns and salmon are in close enough to fish from a kayak. Crankbaits in silver and green or silver and blue are common to represent smelt and alewives though other colors are sometimes better. I've had good luck with a 7" countdown Rapala in silver when wading. All of this is leading up to saying that you want to tie big streamers in white with some olive or blue topping. Tinsel probably helps. Think deep Clouser minnows, deceivers, grizzly hen matukas etc.
I can think of few acts more selfish than refusing a vaccination.