Bring vegetables to a boil with the fish stock and simmer for 1 minute. Tip vegetables and fish stock into a roasting pan large enough for the fish. Place fish, skin side up, on bed of vegetables; it should be just covered with stock. Place roaster in the second rack from the bottom. Cook the fish at 175 °C for 20 minutes. When you look under the fish and it is just pink, it is done.
Remove skin and remove gray layer before serving.
Recipe scales well.