Chordata · chordates
Atlantic bluefin tuna
Thunnus thynnus
Scombridae · tunas & mackerelsIUCN: Least Concern

A giant, warm-bodied tuna that crosses the Atlantic.
Fun factA single bluefin sold for more than $3 million in Tokyo in 2019.
- Waters
- Northeast US, Northwest Atlantic, Northeast Atlantic, Mediterranean & Black Sea
- Depth zone
- Open-ocean surface waters, Continental shelf
- Diet
- Herring, mackerel & squid
- Size
- Up to 3 m, 680 kg
Classification
Chordata › Actinopterygii › Scombriformes › Scombridae
- Kingdom Animalia animals
- Many-celled organisms that eat other living things for energy (heterotrophs)
- Cells have no cell walls
- Most can move at some stage of life
- Clade Bilateria bilateral animals
- Body has a left and right side that mirror each other (bilateral symmetry)
- Head end with concentrated nerves; three tissue layers
- Includes about 99% of all living animal species
- Clade Deuterostomia deuterostomes
- In the embryo, the first opening becomes the anus and the mouth forms second
- Includes echinoderms and chordates
- Phylum Chordata chordates
- At some stage of life: a stiffening rod along the back (notochord)
- A hollow nerve cord along the back (dorsal)
- Slits in the throat (pharyngeal slits) and a tail past the anus
- Subphylum Vertebrata vertebrates
- A skull (cranium) protecting a brain
- Backbone or similar support around the nerve cord
- Includes fishes, amphibians, reptiles, birds, and mammals
- Infraphylum Gnathostomata jawed vertebrates
- Jawed vertebrates: jaws formed from gill arches
- Paired fins or limbs
- Includes all fishes except hagfish and lampreys, plus all tetrapods
- Superclass Osteichthyes bony vertebrates
- Bony vertebrates: skeleton made largely of bone
- Most have a lung or swim bladder
- Includes ray-finned and lobe-finned fishes and all tetrapods
- Class Actinopterygii ray-finned fishes
- Ray-finned fishes: fins are webs of skin held up by thin bony rays
- Usually a gas-filled swim bladder for buoyancy
- About half of all vertebrate species
- Infraclass Teleostei teleost fishes
- Teleosts: symmetrical tail fin
- Jaws that can push forward to grab prey (protrusible)
- About 96% of all living fishes
- Cohort Euteleostei salmon, cod, perch & kin
- A huge group that includes salmon, cod, and all spiny-finned fishes
- Clade Acanthomorpha spiny-rayed fishes
- Spiny-rayed fishes: true spines in the front of the fins
- Includes most familiar marine fishes
- Superorder Acanthopterygii spiny-finned fishes
- Spiny-finned fishes: sharp spines in the front of the dorsal and anal fins
- Pelvic fins usually under the pectoral fins
- Clade Percomorpha perch-like fishes
- The perch-like fishes: the largest group of vertebrates
- Pelvic fins with one spine and five rays (in most)
- Order Scombriformes tunas, mackerels & kin
- Tunas, mackerels, and relatives: streamlined fast swimmers
- Small finlets behind the dorsal and anal fins (in many)
- Family Scombridae tunas & mackerels
- Tunas and mackerels: deeply forked tail
- Tunas keep their bodies warmer than the water
- Genus Thunnus
- Species in the same genus are very close relatives and often look alike.
- Species Thunnus thynnus Atlantic bluefin tuna
Closest relatives in the guide
- Albacore Thunnus alalunga same genus
- Yellowfin tuna Thunnus albacares same genus
- Atlantic bonito Sarda sarda same family
- Atlantic mackerel Scomber scombrus same family
- False albacore Euthynnus alletteratus same family
- Skipjack tuna Katsuwonus pelamis same family
- Spanish mackerel Scomberomorus maculatus same family
- Atlantic butterfish Peprilus triacanthus same order