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FEATURE SPECIES: TUNA

By Roberta Muir

These torpedo-shaped fish with deeply forked tail fins and smooth, almost scaleless, bodies are built for speed. Large schools of them traverse great distances during annual migrations and they can eat up to a quarter of their body weight daily to maintain the energy needed by their muscular, streamlined bodies. Their active muscles are well supplied with blood, giving their flesh a distinctive red colour, making them one of our most highly prized fish, popular even among those who generally prefer red meat.

Tuna is the general name for a number of species belonging to the Thunnini (tuna) and Sardini (bonito) sub-groups (or ‘tribes’) of the Scombridae (mackerels) family. Three of these have major commercial significance in Australia:

Yellowfin Tuna (Thunnus albacares) is named for its distinctive long yellow top and bottom fins. Found right around the Australian coast, it is our most common Tuna. It can vary greatly in size from 4 to 100 kg (50-90cm) and prime specimens are air freighted to Japan where they fetch a high price.

Bigeye Tuna (Thunnus obesus) has an almost cylindrical body and bigger eyes than other family members. It has a dark metallic-blue back with whitish belly and yellow-tipped fins and paler flesh, more pink than deep red. Caught mainly off the south-eastern and south-western coasts, it prefers warmer water temperatures, so supply is lowest during winter. While we do see some of it domestically, it’s mostly exported to Japan, where it is the second most popular sashimi fish.

Southern Bluefin Tuna (Thunnus maccoyii) is Japan’s most popular sashimi fish and a single specimen can command tens of thousands of dollars at Tokyo’s Tsukiji fish market. It’s fished to a very strict quota system in order to ensure a sustainable supply and, needless to say, almost all of it is exported to Japan, with the remainder going primarily to restaurants in Sydney and Melbourne. Caught primarily in the Great Australian Bight and off Tasmania, it is also ranched in sea pens off Port Lincoln. Fish ‘ranching’ differs from fish farming in that juvenile fish are herded from the wild into pens where they’re raised until they reach a marketable size. Attempts to breed Southern Bluefin Tuna in captivity are very close to succeeding, which should bring more of this prized species to the Australian market. This Tuna has blue fins, as its name suggests, but also a bright yellow keel on either side of the tail base and a yellow bar on the tail fin.

Sashimi

‘Sashimi-grade’ refers to very fresh seafood suitable for eating raw (or rare). This is achieved by catching and handling the fish in such a way as to maintain peak freshness and quality. Fish are line-caught, landed onto a mattress (to minimise bruising) and killed instantly by brain-spiking (ike jime). This prevents the fish from struggling and releasing stress hormones and helps keep the body temperature low.

The fish is then bled immediately, removing heat and waste products, and put into an ice slurry to drop the body temperature as close to 0ºC as possible. Ideally sashimi-grade fish should be purchased on the day of consumption; after more than 24 hours in a domestic fridge, while it will still be premium quality, it will no longer be at peak freshness and should be cooked rather than served raw.

SEARED TUNA WITH SALSA VERDE
© Roberta Muir

This vibrant green sauce will keep covered in the fridge for a week; serve drizzled over any fish or meat or as a dipping sauce for cold prawns. If possible, use Ortiz anchovy fillets as they have a much better flavour than other anchovies and are less salty, 1 small can (47.5g) is the right amount.

Serves 4

4 x 200g sashimi-grade tuna steaks
Salt flakes and freshly ground black pepper,to taste
A little extra virgin olive oil
Crusty bread, to serve

Salsa Verde
2 firmly-packed cups flat-leaf parsley leaves
4 cloves garlic, chopped
2 tablespoons capers in brine, rinsed
7 anchovy fillets
½ cup extra virgin olive oil

Make Salsa Verde: combine all ingredients in a food processor or blender and process until smooth.

Remove tuna from the fridge about 30 minutes before cooking, to give it a chance to come to room temperature. Season well with salt and pepper.

Heat a frying pan until very hot, add a little oil and cook tuna on 1 side for about 30 seconds, just until well-coloured, then turn and cook the other side for another 30 seconds, just long enough to colour.

Remove tuna from heat and leave to rest for a couple of minutes before drizzling with Salsa Verde and serving with crusty bread.

Wine suggestion: Australian Chardonnay need not be old-fashioned and over-oaked. Try Fox Creek’s delicious and refreshing Shadows Run Chardonnay 2006. www.foxcreekwines.com

Seared Tuna with Salsa Verde, Photo by Franz Scheurer

SALADE NIÇOISE

This modern adaptation of the classic southern French salad replaces the more traditional canned tuna with fresh.

Serves 4 as a light lunch or entrée

350g waxy potatoes, peeled (such.as kipfler)
170g baby green beans, topped and tailed
400g tuna steaks
Salt flakes and freshly ground black.pepper, to taste
1/3 cup extra virgin olive oil
1 tablespoon red wine vinegar
½ teaspoon Dijon mustard
1 punnet grape or cherry tomatoes, halved
16 small black olives
1 green coral lettuce or other green leaves
2 hardboiled eggs, quartered
8 anchovy fillets, halved

Cut potatoes into bite-sized pieces, and steam for 5 minutes, add beans and continue steaming for a further 5 - 6 minutes, until cooked through. 

Meanwhile, season tuna well with salt and pepper. Heat a non-stick frying pan over a medium heat, add a little of the olive oil and cook tuna, covered, for 3 - 4 minutes, depending on thickness, then turn over and continue cooking, uncovered, until just cooked through (2 - 3 minutes).

Whisk vinegar, mustard, salt, pepper and remaining olive oil together, or shake in a screw-top jar. 

Place potatoes, beans, tomatoes and olives into a bowl. Break tuna into large chunks and add to the bowl. Add dressing and toss gently to combine. Line a large platter or individual plates with lettuce leaves. Spoon salad onto the leaves and garnish with eggs and anchovies.

Wine suggestion: Nepenthe Charleston Pinot Noir 2005 from the ancient soils and cool climate of the Adelaide Hills is truly varietal but approachable. Perfect with this salad served slightly chilled. www.nepenthe.com.au

Salade Niçoise, Photo by Franz Scheurer

 © Roberta Muir