5 Questions to Ask Your Tuna Supplier (Before You Buy)

If a supplier is vague about origin, that’s a red flag. Reputable suppliers will proudly share that their bluefin tuna comes from regulated, sustainable fisheries. Always choose a supplier who can pinpoint the exact region or fishery, as it shows transparency and usually a shorter time from ocean to plate, preserving freshness and quality.

Wild-caught methods can often be associated with overfishing and can have significant impacts on marine ecosystems, have high levels of bycatch, and poor fish welfare during and after capture. Pole-and-line or purse seining with minimal bycatch is preferable. If the tuna is farmed, ask about the farming conditions and diet. Top suppliers will feed tuna a high-quality diet.

Dinko Seafoods combines the best of both fishing methods with our “catch and ranch” fishing method. Wild tuna are corralled into an open pen in the ocean using sardines, so the tuna aren’t distressed or caused any harm. Once the crew has secured the net, our expert divers jump into the water to make sure the tuna are mature enough and the school of fish is large enough. Only sufficiently mature fish (around 17kg or more) are kept, while smaller fish are released to protect populations. If the school meet the size and weight requirements, the crew usher the tuna from the original netting to tow cages. Once the fish are transferred, they spend the next three to six months grazing on sardines, where they grow fatter, rounder and oilier. Once fattened, experienced divers catch the tuna individually by hand to prevent bruising and stress to the fish.

This method not only helped replenish Southern Bluefin Tuna stocks but focuses on increasing the fish’s weight and quality without taking more fish from the ocean. In practice, this means tuna farmed by Dinko Seafood experience a natural life in the wild and then receive a controlled, rich diet in captivity to enhance their flavour and fat content.

The bottom line: whether wild-caught or farmed, a reliable supplier should describe how their methods are sustainable and ethical, and maintain flavourful and high-quality tuna.

Dinko Seafoods’ Southern Bluefin Tuna is premium sashimi-grade Southern Bluefin Tuna. That status is earned by following sustainable fishing methods and strict handling procedures.

Not only are our tuna hand-caught for harvest, but they are super-frozen within hours to -60°C at a state-of-the-art facility. Freezing at ultra-low temperatures locks in the fish’s “ocean fresh” quality, eliminates the need for any harmful gases or preservatives to maintain colour, and removes any risk of parasites, making it safe for raw consumption. When thawed properly, the tuna’s texture and taste are as good as fresh-caught. Not all suppliers have this capability, so it’s a key question to ask.

Sashimi-grade tuna will have a deep, even colour and a fresh, clean smell. A knowledgeable supplier will proudly affirm that their tuna can be eaten raw and explain how they achieve that level of quality. If they can’t, you might not be getting the top-tier fish you’re after.

Not only is this method the most ethical, as it minimises the stress to the fish, but it prevents lactic acid build-up which increased the quality of the meat. Dinko employs iki jime within seconds of the tuna leaving the water, ensuring the fish doesn’t suffer, and the flesh stays in peak condition.

Next, ask whether the tuna is handled individually or in small batches. Bruising can be a problem if fish are treated roughly. Dinko’s harvest process involves expert divers catching tuna one by one by hand during harvest to avoid bruising the meat.

Finally, ask about preservation. Key things to listen for include how quickly the fish is chilled or frozen, the method of freezing, and how it’s packaged. The goal is to prevent deterioration from the moment the tuna leaves the water. Tuna should be frozen immediately after catch, and kept at the correct temperature all the way to your kitchen. A reliable supplier will use vacuum-sealed packaging and continuous refrigeration or freezing. When your supplier can clearly explain these practices, you know your tuna will arrive as fresh and flavorful as possible.