Tuna

Photo: Marion van Dijk
Tuna is a prized fish, a fish of the high seas, a roamer and fast swimmer. In New Zealand, tuna is not so commonly eaten or understood. For many, tuna is fish in a can. used in tuna sandwiches and tuna salad but not much else.

Having visited several Pacific Island fish markets, marvelling at the colour and array of the fish caught in tropical waters, I am always impressed by the different tuna available in the Pacific.

The tuna available to us in New Zealand fish shops and specialty supermarkets comes from Fiji for the most part, with a small amount fished from New Zealand waters during summer, when tuna migrate here.

Tuna are warm blooded, migratory fish, which spawn in the warmth of the tropics and travel extensively throughout the Pacific and Atlantic. There are nearly 50 tuna species. They are from the Scombridae family – mackerel, in fact.

Most of the commercially fished tuna belong to the Thunnus genus. These include albacore, yellowfin, bigeye and bluefin. Albacore, yellowfin and bigeye are readily available in New Zealand, as is skipjack, which belongs to another genus.

Albacore is a pink-fleshed fish and is often used in the commercial canning of tuna, as is skipjack. Otherwise, these two species are often smoked.

The Japanese also dry skipjack, where it is known as katsuo.

Bluefin, yellowfin and bigeye are deep-red coloured. The red colour comes from the fact that tuna muscle has high levels of myoglobin, an oxygen-binding molecule, and it is this red-fleshed tuna that is so often served as sashimi.

Around the world, the desire for the deep-red flesh of tuna has increased so much in recent years that there is increasing concern for its sustainability, particularly bluefin tuna. Arguments rage between conservationists, fishing companies and governments about fishing practices in pursuit of these deep-water giants. As the price of tuna increases, and with it the desire for bluefin, particularly among the Japanese, who regard it as the prize of prizes for sashimi, we are left with frenzied fishing practices.

Poor fishing practices aside and from a culinary perspective, the fish is delicious, so let's hope that we can continue to enjoy the delights of tuna.

As a nation, New Zealanders' consumption of tuna could not in any way be said to contribute to abuse of the species.

Tuna is an oily fish and has lots of vitamin D and omega 3. Some tuna, especially longer-living, larger fish, can contain low levels of mercury.

Opinions about mercury levels are as varied and volatile as the debate about fishing practices. However, on the other side, there has recently been recognition of the valuable levels of selenium in tuna. Inform yourselves about the debate.
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It is good to be aware of all the pluses and minuses of what we choose to eat.

SASHIMI TUNA
Photo:Marion van Dijk
Having spent a lot of time in Samoa, including a very recent visit there, I always enjoy platefuls of thinly sliced, very fresh, tender and tasty sashimi.

Served just with wasabi soy sauce, the fish melts in the mouth. Tuna sashimi can be found on every menu in Samoa.

In a recent article, I described salmon sashimi. Tuna sashimi is prepared similarly and is as delicious as salmon – both fish can be enjoyed together on a platter as an entree.

The key to tuna sashimi is extremely fresh fish. It should be moist, shiny, bright and firm to the feel, and smell only of the sea.

Guytons fresh-fish store on the Nelson waterfront gets bigeye or yellowfin tuna twice a week on Tuesdays and Thursdays. It retails for $39 a kilogram. For a sashimi first course, buy about 200g for 4 people.

Take a very sharp knife, then cut through the flesh at 90 degrees, across the grain. Slice through the fish in one motion. Make the slices fine. Thick slices of raw fish are hard to swallow.

Allow at least 4-5 slices per person. Serve with soy sauce, add wasabi to taste and mix together well. Add some grated daikon radish and pickled ginger for an additional flavour and texture.

SEARED TUNA

To prepare fresh tuna, buy a piece of tuna big enough to be cut into steaks about 2.5cm thick for each person being served, or it could be cut into pieces about 7.5cm thick and cooked on all four sides, then sliced into individual portions.

Tuna is like beef in that it can be eaten rare, medium-rare or well done. I think it is a real shame to overcook it. Well-done tuna becomes tough and dry, and anything cooked beyond medium will be dry. Cooked rare, it melts in your mouth, soft and tender on the inside with a crust of crispness seared on the outside.

Coat the outside of the tuna steaks with lots of crushed salt and pepper, rubbing this into the surface of the fish.

Heat a pan with a little oil until it is very hot, or use a barbecue.

Place the tuna steak in the pan or on the hotplate and cook it for 90 seconds on the first side and then repeat for the second side. If you want to cook the thicker version, cook the four sides for about 45 seconds each.

Serve the seared tuna with romesco sauce and garlic mashed potatoes.

ROMESCO SAUCE

2 red peppers
2 red chillies
4 tomatoes
4 cloves of garlic
3/4 cup of toasted hazelnuts with the skins removed
1 1/2 cups of coriander or parsley
1/4 cup of extra-virgin olive oil

Slice the tomatoes in half and slow roast them in a moderate oven (150 degrees Celsius) until they are soft and tender, for about 45 minutes. Roast the hazelnuts in the oven with the tomatoes until they are golden. Cool and remove the skins by rubbing the nuts in your hands.

Roast the red peppers by placing them directly over a gas flame until they are charred all over. Peel them immediately in cold running water, although some people like to put the peppers in a plastic bag for 10 minutes as an alternative. Break them apart and get rid of the seeds and membranes. Set aside.

Do the same with the chillies. Char them quickly, because the skins are thinner than those of red peppers and disintegrate easily.

Cook the garlic in the olive oil until golden and leave to cool. While it is cooling, combine the other ingredients, including the herbs in a food processor. Add the oil and garlic and season to taste.

SALAD NICOISE
Photo:Marion Van Dijk
This is the classic French recipe for this salad. It is a salad that is popular and there are many adaptations of it. This is taken from Julia Child's Mastering the Art of French Cooking. It is a great summer salad. Child used canned tuna in her recipe, but fresh tuna can be substituted. For 4 people:

Either 250g of fresh, seared tuna or a 250g can of good-quality tuna
2 cups of blanched french beans
2 tomatoes
Cos lettuce leaves
4 potatoes cooked and cooled, and sliced/diced. While they are still warm, toss them gently in a mixture of lemon juice and a dash of white wine.
1/4 cup of pitted black olives
2 hard-boiled eggs, cut into quarters
6 anchovy fillets
Fresh herbs, such as basil and parsley
A dressing of 3 Tbsp of extra-virgin olive oil, 1 Tbsp of white-wine vinegar, 1 tsp of Dijon mustard, and salt and black pepper, mixed well together.

If using fresh tuna, sear it as outlined above. Leave it to cool and then refrigerate it. When it is cold, cut it into slices. To assemble the salad, combine all the ingredients on a platter, drizzle over the dressing and serve.