Fish provides another class of high-protein or tissue-building food. As this term is generally understood, it includes both vertebrate fish that is, fish having a backbone such as salmon, cod, shad etc. and many other water animals such as lobsters, crabs, shrimp, oysters and clams. Fish can usually be purchased at a lower price than many other food items and for this reason possesses an economic advantage over them. Some varieties of fish are sought more than others, the popularity of certain kinds depending on the individual taste or the preference of the people in a particular locality.