Very few boats will be able to keep crustacions live for any length of time. Frozen prawns, and coons cure up better in my experience. Always start with frozen, or as close to frozen as you can manage after breaking up the coon bricks. Curing frozen vs. fresh... I doubt you'll notice a difference. The fish will once your fresh cured prawns rot after a week or so, but not if they've been cooked before hand. Try em frozen first. Easier to acquire, and highly effective at luring steelhead.

Crowes, D&G, and BC Angling Post have them frozen... Not sure about places up north, but crowes, and D&G ship. The good ol F/V Acadienne Gale 2 did some great processing this year! Too bad the springer season is a bit under par, because the prawns, and coons are stellar! Best prawns I've seen, perhaps ever!