All the larger kinds of whale are threatened with extinction. Although whales are protected from hunting by international law, there are many loopholes that are exploited. A new threat comes from the commercial exploitation of krill, the tiny crustaceans that form the bulk of the diet of the huge blue whales and some of smaller relatives. Krill are being harvested in huge quantities by fishing boats, for use as fertilizer and as food. If their stocks are reduced, the whales will have no alternative food sources.
Picture credit: google