Put the clams in a pan with 1 cup of water and steam for 5 minutes until they open.
Through a fine sieve, train the liquid and reserve. Take the clams out of their shells; discard those which have not opened.
Bring the remaining 8 cups of water to boil and put in the langostinos and the crayfish. Cook for 4 minutes. Remove from the water and shell them. Put necessary the shells of the shellfish in a processor or blender with 1 cup of the liquid and blend until smooth. Press through a fine sieve if necessary. Return this puree to the shellfish broth with the chopped vegetables and the sliced squid. Cook for 15 minutes.
Fry the tomato sauce ingredients in hot oil for 15 minutes until thick. Add the boiled langostinos and crayfish, the cut up corvine and the clams. Cook for 5 minutes and add to the shellfish broth with the tomato paste and reserved liquid from the clams. Simmer for 10 minutes.
Add the wine or sherry. Cook for a further minute. Taste for seasoning. Add the cream and mix well. Do not let the soup re-boil.
Serve in small earthenware dishes.