The yellowfin tuna is among the larger tuna species, reaching weights over 180 kg (400 lb), but is significantly smaller than the Atlantic and Pacific bluefin tunas, which can reach over 450 kg (990 lb), and slightly smaller than the bigeye tuna and the southern bluefin tuna. Although mainly found in deep offshore waters, yellowfin tuna may approach shore when suitable conditions exist. Mid-ocean islands such as the Hawaiian archipelago, other island groups in the Western Pacific, Caribbean, and Maldives islands Indian Ocean, as well as the volcanic islands of the Atlantic such as Ascension Island and Saint Helena, often harbor yellowfin feeding on the baitfish these spots concentrate close to the shoreline. Yellowfin may venture well inshore of the continental shelf when water temperature and clarity are suitable and food is abundant. Yellowfin tuna often travel in schools with similarly sized companions. They sometimes school with other tuna species and mixed schools of small yellowfin, and skipjack tuna, in particular, are commonplace. They are often associated with various species of dolphins or porpoises, as well as with larger marine creatures such as whales and whale sharks. They also associate with drifting flotsam such as logs and pallets, and sonic tagging indicates some follow moving vessels. Hawaiian yellowfins associate with anchored fish aggregation devices and with certain sections of the 50-fathom curve.