Bluefin tuna chase down their prey using their ability to swim at very high speeds.
They can also use modified filter feeding to catch small, slow moving organisms. They have also been known to eat kelp. They form feeding aggregations throughout the Atlantic and Pacific outside of the spawning season. Very little feeding occurs during spawning season. (Agustin, Sampang, and Luna, 2005; Figaro, 2005; Gardieff, 2005; Jeffries, 2005; Marinebio.org, 2005; Miyashita et al., 2001; Scott, 1997; Tudela, 2001)
Larvae feed on small organisms such as brine shrimp, other fish larvae, and rotifers. Juveniles also feed on small organisms until they become large enough to start feeding on small fish. The prey of adults include smaller fish, squid, eels, and crustaceans.