A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: 50 cm or 1.6 ft, weight: 1.8 kg or 4 lb) up to the Atlantic bluefin tuna (max length: 4.6 m or 15 ft, weight: 684 kg or 1,508 lb), which averages 2 m (6.6 ft) and is believed to live up to 50 years.
Tuna, opah and mackerel sharks are the only species of fish that can maintain a body temperature higher than that of the surrounding water. An active and agile predator, the tuna has a sleek, streamlined body, and is among the fastest-swimming pelagic fish – the yellowfin tuna, for example, is capable of speeds of up to 75 km/h (47 mph).
You require a nice thick steak or it will be overcooked in a matter of seconds.
Serve with a simple rocket or leafy salad with cherry tomatoes that have been slightly roasted in the oven, drizzled in a little oil or with grilled leeks, as ever, it is your choice.
Finally serve with a sprinkling of black and white sesame seeds atop the steak.
Download the .pdf from this link: Tuna Steak with a Lemon Caper Sauce