Yellowfin tuna have torpedo-shaped bodies with dark metallic blue backs, yellow sides, and a silver belly.
They have very long anal and dorsal fins reaching almost as far back as the tail and giving the appearance of sickles or scimitars.
Yellowfin tuna can grow up to 2.1 m in length and weigh up to 200 kg. They are commonly caught in distinct size classes ranging from 20 to 50kg.
Yellowfin tuna is the most valuable species caught in the Eastern Tuna and Billfish Fishery, accounting for nearly half of the gross value of production.
The biggest yellowfin tuna captured in the world weighed 217 kg.
Yellowfin tunas are extremely strong swimmers with bursts of speed around 65–75 km/hr.
Yellowfin tuna commonly school in the same size class, and often with other species of tuna.
It is important to know which cut of the tuna you have when deciding how you will cook or serve it:
The belly of the tuna has a higher fat content requiring much less heat to bring out the flavours. Caution when grilling this cut on the barbeque as the oil may burn leaving an acrid flavour. It is much better to use the back loin, which has a lower oil content.
Cutlets and steaks can be cooked by grilling, barbecuing, baking, smoking, poaching or marinating.
Yellowfin tuna has superb eating qualities when eaten as sashimi (raw).
Grilled or barbecued, tunas are best seared and left rare centrally. Highlight with intense flavours such as charred capsicum, eggplant, balsamic vinegar and olive oil dressings on a bed of bitter greens and aioli, roasted garlic, and Japanese wasabi, soy and pickled ginger.
Tuna is an excellent dish sliced thinly and briefly dropped into simmering “fish stock” or cooked as an Asian “hot-pot” to each diner’s preference.