I use the food saver vacuum packer that I use on my deer and wild turkey. Before that I used ziploc backs and just got as much air out as possible.

By the way, I like to use a hack saw to cut across the back of the head where the gill plate starts and cut half way down or so to get a good spot to start the cut with the tin snips. EMT shears work pretty good too. The hack saw really is a time saver there. A few guys had a shoot last year at Glen Elder lake in Western KS and thought they would try some cordless reciprocating saws and cut off saws; guess one of them was a contractor or something. Anyhow...guess it didn't work out as well as they thought and slung stuff every which way!