I just got a vaccuum sealer for Christmas, but before I had that I would fillet the panfish and freeze them in a tupper ware container in water, which would become a block of ice. The fillets keep for a very long time frozen this way. If you only have a few fillets, just cover what you have and freeze, leaving room in the container. When you get more fillets drop them on top of the previous ones and add more water.
If the pond you are on is smaller and has an abundant biomass of blue gills, their size may get stunted due to too much competiton. I would determine an average size for the impoundment based on summer catch and release fishing, and keep as many fish through the ice as legally allowable, below the average size, and return any fish at or exceeding the average size, basically returning the biggest breeders.
I'd do the same with the crappie.
If I was into a good bite and was going to be making a mess any way, I'd fillet 5" gills.
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