Little Tunny

• GeneralIt shoals in numbers that set the surface boiling as it hunts sardines.
• Like the other tunas, it keeps its muscles above the temperature of the water thanks to a network of blood vessels that recovers heat, which lets it swim faster and for longer.
• It cannot stop swimming: it has to keep water flowing over its gills in order to breathe.
• It forms large schools mixed with other scombrids of similar size, and groups itself by size.
• It is among the least commercially valued tunas because of its dark flesh, and a good share of its catch goes to cheap canning, to bait or to local consumption.
• Like the other tunas, it is a regional endotherm: it keeps parts of its body above water temperature thanks to a countercurrent heat-exchange system.
• It must swim continuously to breathe, because it ventilates its gills through its own forward motion.

Skeleton type

Vertebrate - internal bony skeleton (fish)

Habitat and environment

Warm surface waters over the shelf

Sources consulted: FishBase (Froese & Pauly, eds.); Lista Roja de la UICN; Collette y Nauen, FAO Species Catalogue