Bluefin tuna are large, fast-swimming predatory fish found throughout various ocean basins. These powerful marine inhabitants are top predators, with diets and feeding behaviors supporting their substantial size and active, migratory lifestyles.
Primary Prey
Bluefin tuna primarily consume smaller schooling fish, cephalopods, and crustaceans. Their diet includes high-energy, protein-rich species such as mackerel, herring, anchovies, and sardines. Other fish like whiting, flying fish, mullet, sand lance, bluefish, and eels also form part of their regular intake. Beyond fish, they prey on various cephalopods, with squid being a common food source. They also incorporate crustaceans, including pelagic red crab and shrimp, into their diet.
Juvenile bluefin tuna begin by consuming tiny zooplankton, gradually shifting to larger prey as they grow. While their diet mainly consists of pelagic species, they are opportunistic feeders. They can occasionally consume demersal species or items like starfish and kelp when feeding near shore, ensuring they acquire the energy needed for their activities.
Dietary Adaptations
The diet of bluefin tuna varies depending on their age, size, geographic location, and the season. Younger tuna target smaller prey compared to the larger bony fish and invertebrates consumed by adults. This shift in prey size corresponds with the tuna’s growth and increasing caloric demands. Their migratory nature means they encounter different food sources across diverse ocean environments.
Regional and seasonal prey availability influences their feeding patterns. For example, in New England, sand lance, Atlantic herring, Atlantic mackerel, and squid are frequently consumed. In areas like the Bay of Biscay, their diet might feature krill and anchovy, with consumption rates shifting based on annual abundance. During spawning seasons, bluefin tuna feed less, focusing energy on reproduction.
Hunting Strategies
Bluefin tuna employ sophisticated methods to capture prey, using their speed and agility. They are among the fastest fish, reaching high speeds to ambush or pursue prey. Their torpedo-shaped bodies allow for rapid acceleration and efficient movement. As opportunistic predators, they adapt their hunting to whatever prey is most available.
They often hunt collectively in schools, a strategy that helps corral and disorient large groups of smaller fish. This coordinated effort maximizes hunting success. A common technique is “ram feeding,” where they swim with mouths open to force water and prey over their gills. Bluefin tuna also engage in active pursuit, chasing down fast-moving schooling fish. They hunt by sight and dive to significant depths for food, often concentrating efforts around dawn, midday, and dusk.