"Cape Cod Turkey" means a codfish dish. Cape Cod friends of mine always make cod for Thanksgiving, figuring that that is most of what the Pilgrims had for dinner.
They make baked stuffed cod, which is a delicious thing as long as you do not overcook the fish. Let's face it - Thanksgiving is about stuffing, gravy, cranberry sauce, and punkin pie anyway and not so much about the turkey. Well, Mrs. BD makes Butternut Squash pies but it's the same difference.
There is a specific New England dish called Cape Cod Turkey. Cod and potatoes.