CUT THE FISH IN 3 cm PIECES. Place all ingredients except casings in a food processor and pulse until coarsely chopped. Or, pass all the ingredients through a meat grinder fitted with medium holes. Stuff the mixture into sausage casings or form 2 long sausages in plastic wrap. Poach the sausages in gently simmering water for 5 minutes, drain and let cool. If you have used plastic wrap to form the sausages, remove it when sausages are cool. Cut sausages into 15 cm lengths. To serve, grill the sausages or place under a preheated broiler. Since the sausages are already cooked, we want only to reheat them and crisp their skins. Makes 8 Sausages, or 4 Servings