Behavior[edit]
Bluefin dive to depths of 1,000 metres (550 ftm).[18] They can reach speeds of 40 miles per hour (64 km/h).[9]
Diet and foraging[edit]
The Atlantic bluefin tuna typically hunts small fish and invertebrates such as sardines, herring, mackerel, squid and crustaceans.
Parasites[edit]
The tetraphyllidean tapeworm Pelichnibothrium speciosum parasitizes this species (Scholz et al. 1998). As the tapeworm's definite host is the blue shark which does not generally seem to feed on tuna[citation needed], it is likely that the Atlantic bluefin tuna is a dead-end host for P. speciosum.
Reproduction[edit]
Female bluefin are thought to produce up to 30 million eggs.
Atlantic bluefin tuna spawn in two widely separated areas. One spawning ground exists in the western Mediterranean, particularly in the area of the Balearic Islands. The other important spawning ground of the Atlantic bluefin is the Gulf of Mexico. Pop-up satellite tracking results appear to confirm in large measure the belief held by many scientists and fishermen that although bluefin that were spawned in each area may forage widely across the Atlantic, they return to the same area to spawn.
Atlantic bluefin group together in large concentrations to spawn, and at such times are highly vulnerable to commercial fishing. This is particularly so in the Mediterranean where the groups of spawning bluefin can be spotted from the air by light aircraft and purse seines directed to set around the schools.
The western and eastern populations of Atlantic bluefin tuna are thought to mature at different ages. It is thought that bluefin born in the east reach maturity a year or two earlier than those spawned in the west.[18]