Preheat the oven to 190°C (Gas Mark 5) for conventional oven or 170°C for fan assisted oven. Place the fish skin side down in a suitable dish or in a pouch made up from a square of aluminium foil, lined with parchment if you prefer (remember to leave a little head room for steam). You can place it on slices of lemon and finish with a knob of butter and seasoning to give an even better taste experience.
These times are all approximate guidelines as wild, world class NI seafood comes in all shapes and sizes! To test if your fish is cooked, open the foil pouch and insert a thin table knife or a fork down through one of the ‘seams’ in the thickest part of the flesh (i.e. the natural lines that run through fish flesh) as in the image above. Gently pry the flesh open and make sure the fish is no longer translucent, but opaque (white and creamy for whitefish).