The primary source of protein for most of the world population is fish. The world over, the annual sea fish harvest is from 85 and 130 million metric tons (including aquaculture). There are over 29,000 species of fish. Fish and shellfish consumption varies by species of fish. The type of fish consumed in a particular part of the world would depend mostly on the fish that are locally available. Some of the types of fish that are most commonly consumed include salmon, cod, anchovy, carp and tuna. In the United States of America, the fish that is consumed the most is canned tuna. It is ironical to note that the FDA has warned that particular kinds of tuna have relatively high levels of mercury compared to other fish. One of the most consumed raw fish is shrimp.