Knifing A Giant Tuna Fish

Text and Images by Catherine Ling @ Makansutra

The Halia at the Botanic Gardens is celebrating its 11th anniversary with a series of educational dinners on food transparency, or knowing your food sources from farm to fork. Kicking off the first evening was a demo on “loining” or cutting up an entire Australian Southern Bluefin Tuna (SBT). Bluefin tuna is notoriously overfished, but this particular fish was farmed on a sustainable basis. Here’s how they turned this beast from fish to food.

Knifing A Giant Tuna Fish

This bluefin tuna is a whopping 62kg and needed three men to carry it. Guest chef Dan Segall (extreme right) led the cutting or loining, assisted by Richard Davies (second from right), the General Manager and Executive Chef of The Halia.

Knifing A Giant Tuna Fish

Dan first uses a saw-like knife to remove the head.

Knifing A Giant Tuna Fish

He says the head is the best part – you get all the connective tissue from around the eyes, the cheeks and the meaty head.

Knifing A Giant Tuna Fish

Next, the tail comes off. That part is a lot easier than the head.

Knifing A Giant Tuna Fish

Dan jokes that this is what you get if you pay only $7 per kilo.

Knifing A Giant Tuna Fish

He then slices off the pectoral fin, which includes the collar. The Japanese like this part that they call “kama”. It stretches from the otoro belly to the head just behind the gills.

Knifing A Giant Tuna Fish

Dan then makes a lateral incision all the way to the spine. A tuna fish is built differently from most other fish which you would fillet by cutting off one side and then the other. The tuna’s spine runs down the middle like a cross, so the meat is arranged in quadrants.

Knifing A Giant Tuna Fish

The chef then cuts the fish from the top, so you get the first quarter section of the fish out. Dan says methods and styles of loining vary in Japan, mostly according to region.

Knifing A Giant Tuna Fish

That’s the top right quadrant of the fish sliced off the bones. It’s a heavy chunk.

Knifing A Giant Tuna Fish

Now for the lower quadrant – the belly is sliced right through, and the rest of the meat is sliced off the spine. This belly area is where the highly prized otoro lies.

Knifing A Giant Tuna Fish

Of course, there’s little bits of meat still stuck on the spine. Every gram counts in sashimi grade tuna, so the chef scrapes whatever he can using a spoon. You can use that for nakaochi tuna tartare, for example. Dan reveals that he and his chef friends used to come to a tuna loining with warm bowls of rice. They would try to meet the challenge of finishing the loining before the rice gets cold, so they could scrape these bits onto the rice to enjoy.

Knifing A Giant Tuna Fish

The final fish cleaned up. You repeat the same cutting procedure on the other side to complete the whole loining process, or you can keep the fish for another dinner..

Knifing A Giant Tuna Fish

This is the whole back loin.

Knifing A Giant Tuna Fish

Here’s the chutoro (reddish top part) and otoro (white bottom part), the richest and fattiest part of the fish. Ironically, the otoro was, until the 1950s, just thrown away or used as cat food. Today with its fatty marbling, it’s the wagyu equivalent of tuna.

Knifing A Giant Tuna Fish

Richard Davies removing the sinews from the otoro and cutting it into slabs.

Knifing A Giant Tuna Fish

This is where it all starts to look much more familiar – beautiful slabs ready for the sushi counter.

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