Blue whales filter their food through their baleen plates. Blue whales eat krill (euphausiids) and copepods. A blue whale can eat up to 8,000 lbs. of krill during its peak consumption period. It is estimated to take 2,200 lbs. of food to fill a blue whale's stomach.
A 2002 report estimated there were 5,000 to 12,000 blue whales worldwide, in at least five groups. The IUCN estimates that there are probably between 10,000 and 25,000 blue whales worldwide today.