Opening the freezer would have substantially decreased the frozen time, with each opening. Specifically as OP seemed to specify an upright freezer.

Chest freezer would have had less of an impact, but still noticeable.

I guess having a good stock of malt vinegar and plenty of jars around would be helpful so you can make a lot of pickled fish.

You want to be very careful about pickling food of unknown freshness - if the meat had turned pickling will do nothing except provide a wonderful breeding ground for a lot of really fun bacteria.