These include krill, crab larvae, jellyfish, sardines, anchovies, mackerels, small tunas, and squid. Other predators include tunas, sharks, swordfish, sea turtles and penguins. Other fish like the tunas, billfish and Lamnid sharks also possess this ability. About 80% of the caught Atlantic and Pacific bluefin tunas are consumed in Japan. Off Madagascar, spinner sharks follow migrating schools of mackerel, tunas, and jacks. Respiratory systems of southern bluefin tunas are adapted to their high oxygen demand. So, in addition to being endotherms, bluefin tunas are also thermoregulators. It preys mainly on teleost fishes, including ponyfishes, grunters, tunas, and herring. Most of the bony fish findings represent tunas and croakers. However, is outside, or at the upper limit, of temperature tolerances for bluefin tunas. Most of the bony fish findings belonged to tunas and croakers. Many species of dolphins accompany large tunas on hunting expeditions, following large schools of fish. Popular protein ingredients are fish cakes, imitation crab meat, eggs, tunas, or shrimps. Argonauts are preyed upon by tunas, billfishes, and dolphins. The organization's research and conservation efforts also focus on sea otters, various birds, and tunas.