Have a pot of water ready to cook the noodles. While making the soup, cook the noodles according to the package instructions and drain.
Prepare the vegetables.
Stir in the onion, carrot, cabbage, zucchini and optional mushrooms. Lightly salt, and cook until the vegetables are slightly softened, about 2 minutes, stirring occasionally.
Add the seafood starting with the clams, which require more time to cook, followed by the mussels, shrimps and squid. Bring everything to a boil. Salt and pepper to taste.