Baked Galway Codling with Mussels or Cockles

The Irish are discriminating in their purchases of cod and are partial to the smaller cod which are often taken by Galway boats. This dish combines codling with mussels (or cockles) in an agreeable way. It may be made with either a whole codling or fillets. Cooking time will be longer if you use a whole fish; and the parboiling of the vegetables should then be briefer.