Nowadays, the incidence of cardiovascular disease has increased to such an extent that the consumer now prefers food with low cholesterol content and select processed food with nutritional labeling. In an extensive survey of cholesterol content of Indian fish and shellfish it was found that shellfish especially prawns, squid and cuttle fish had higher levels of cholesterol compared to other fish and shellfish. The fish fat and cholesterol content might vary with habitat and size of the fish. Keeping in view the nutritional and health importance of biochemical constituents of fish, the consequence of seasonal variations in cholesterol content and other biochemical constituents in Indian mackerel and Indian squid is detailed in this book.