Some of the common ingredients in a Seafood Chowder may include clam broth, potatoes, clams, shrimp, fish, celery, butter, milk or cream, sweet peppers, onions, herbs, spices, and flavorings. Russet potatoes are most often used as a thickener for Seafood Chowders since they contain higher levels of starch but are low in moisture content. As an alternative, a roux can also be used to thicken this type of soup. Seafood Chowders will vary in flavor and ingredients throughout the world, but regardless of where the Chowder is made, it most often provides a savory mixture of seafoods that are very rich in flavor.