Here's what the DFO site has to say about that:
"What I get from that is the fish counts towards your possession limit up until it has been consumed. Once it has been consumed, it not longer counts as it's no longer in your possession. (At least until you hit the bathroom the next morning

)
Like FD said, I doubt you'd be cooking up a 20lb spring unless you have a large group. If it's a pink or coho or sockeye then go for it I say.