Burying a fish as a Christmas tradition? To me this almost sounds like a joke, and I want to know if this is really a tradition...

I was at a dinner tonight with some vendors, one of whom was from New England.  He was telling the group about a catholic tradition of burying a dead fish in the back yard on Christmas.  He wasn't Catholic himself, and couldn't elaborate, but swore his friend's family did this as a tradition, and that it was a "Catholic thing".

Google is coming up blank, so I'm asking our Catholicism experts here:  Is this truly a tradition, and if so, what can you tell me about it? Origins, meanings, etc.
Rakfisk is a traditional Norwegian dish, which is made by burying trout or char in the ground for several months, and then eaten without cooking. It is traditionally eaten around Christmas, but it is not a specifically Christian tradition (any more than turkey or mince pies). Since it is eaten at Christmas, the burying would have to have happened several months before, unless the fish is buried for an entire year. Norway is not a particularly Catholic country, so it is unlikely to have been a Catholic tradition.