ShanaRae Lim Oysters are classified as shellfish, covered with a shell, or invertebrates, having no backbone. They are further classified as mollusks, mollusks are of soft structure and are either partially or wholly enclosed in a hard shell that is largely of mineral composition. All shellfish have some carbohydrate in the form of glycogen. Oysters have from 3 to 5 percent. Oysters also contain a somewhat higher percentage of calcium than other fish and meats, which are notably low in calcium.
Marine fish are a dependable source of iodine.
Oysters, clams, and lobster are the highest in iodine of all seafood. When alive, they have a tightly closed shell. Gaping shells indicate that they are dead and therefore no longer usable. Shucked oyters should be plump and have a natural creamy coolor, with clear liquor. This information was made possible by Marion Bennion from her textbook Introductory Foods.