Can you make soup or stock with just Canada whelks, no meat?
yes, you can just use vegetables and seafood for you recipe, the result will be different; you can use a strong vegetarian broth or a seafood/fish stock.
If using only vegetarian and fish/seafood ingredients, it will taste fishy; that's the point, isn't it ? Depending on the base stock (vegetarian or fish), you might get different results.


About whelk, I've got no experience cooking with them, I only use brined ones and eat them as-is.