Welcome to the website of Seafood Services Japan (SSJ)
We offer a range of services from importing, exporting, product quality and market assessment, to general consulting on all things seafood in Japan and elsewhere. The managing director and founder, Alistair Douglas, did his PhD in the quality, cold-chain management and traceabiltiy of farmed Southern bluefin tuna from Australia to Japan.
Below is an exmaple of his work on the Tsukiji market where he spent five years researching tuna quality assessment and market forces.
Which of these two fish is better than the other?
Does it matter much? Well on Friday the 5th of January, 2001 a single 202kg bluefin tuna, caught in the Strait of Tsugaru off Aomori Prefecture, sold for 20.2 million yen at the Tsukiji Wholesale Market in Tokyo, Japan -that’s US$175,000. This was the auction price paid by a single wholesaler – he still had his commission to add, as did the restaurateurs!
Was it just a moment of madness? What made this fish so valuable? What is the difference between a ‘good fish’ and a ‘bad fish’? Can we measure these differences? If the same fish had not been killed using the “ikijime” method, if it had struggled on the deck of the boat, if it had been dropped from a crane, and if it had not been shipped to the market in a constant low-temperature environment would it have still been worth the same value? At about $1,500/hr this bluefin tuna would possibly have been the fastest depreciating item in world history!
Anyway, back to the question, which is better?????
OK. What if we set up a digital camera and a constant luminescent torch at a pre-determined distance and angle and take a digital image of the tail cut of each tuna. So we end up with these images – does this help? Which is better – left or right?
What can we do to help us? What information can we extract from these images? Well if we use off-the-shelf imaging software we can extract values for red, green, and blue - the three primary colours (RGB). So let’s take a look at the RGB values from a particular region of the tail cut from each tuna as shown below.
The tuna image on the left gave us R, G, & B values of 125, 65, 48, and the tuna on the right gave us values of 139, 72 and 39 respectively. So what does this mean? We know redness is important in the assessment of sashimi grade tuna. What if we express these numbers as a ratio of red to the other colours? So let’s divide the red value by the sum of the green and blue values. Using this we get 1.10 and 1.25 for left and right tuna respectively. Does this help? Not really. Do we need to spend years on the markets before we can tell which tuna is better?
OK. Let’s ask an expert - Mr. Murakami. He’s been selling tuna at the Tsukiji Central Wholesale Market for over 20 years. Let’s ask him to grade the tuna’s quality using either an A, B or C grade – A being the best and C being the worst. Well according to Mr. Murakami the tuna on the left is a C and the tuna on the right is an A. So the tuna with a higher RGB ratio (1.25) is an A and the tuna with the lower ratio (1.10) is a C.
That’s interesting. What about a second opinion? Well rather than ask more people let’s see what these men think – or more to the point – what their wallets think. These men have been buying tuna at auctions at the Tsukiji market for a combined number of years that measure in the hundreds. At the auction the tuna with a 1.25 RGB ratio sold to one wholesaler who bid 3500 yen/kg for it, and the tuna with a 1.10 RGB ratio sold to a wholesaler who bid 2800 yen/kg for it. So there you have it – the tuna on the right is ‘better’ than the tuna on the left according to the experts and the digital ‘eye’.
Interesting result yes? Well that was just once. How about we do this for a whole year with hundreds of fish…. Amazingly it appears there is a relationship and that my digital eye didn’t fluke this. In the graph below you can see that A grade fish according to Mr. Murakami had higher RGB ratios than B or C grade fish. Also, according to all the wholesalers that bought fish in this year, they thought fish with a higher RGB ratio and ranked high by Mr. Murakami were worth paying more for – of course this was without them knowing either prior to the auction.
The above is an example of some of the research conducted within the Aquafin CRC by Alistair Douglas of SSJ on behalf of the Southern bluefin tuna farming industry located in Port Lincoln, South Australia. The finding highlighted the potential of using digital camera technology to rapidly and non-destructively assess the quality of the flesh of farmed Southern bluefin tuna according to the experts that buy it at its main market in Japan.
So how do you measure quality?
If you work in the seafood industry how do you measure the quality of the product you produce, handle or sell? If you are a fisher, how do you preserve quality? If an aquaculturist, how do you enhance quality? Indeed, what does ‘quality’ mean in the context of your product and what qualities do your customers want and how do you provide them? What are the intangible qualities of the product – the feelings of safety, security, and sense of ‘goodness’ when buying and consuming your product?
Along with its collaborators, it is these challenges that SSJ strives to address. SSJ works with not only premium producers committed to continual improvement, but also with like-mined service providers within the supply chain. Through SSJ’s provision of Safety Testing & Quality Measurement, Cold Chain Management, Traceability, Customer Support Services, and Marketing and Promotions the company not only manages information but we also generate it too. We offer seafood producers a gateway to their customers and help them to continually define and meet their customer’s needs, and, in so doing, improve the reputation, competitiveness, and profitability of the producer. Please read our other sections to find out what makes SSJ different and how we achieve the above.
Alistair E. Douglas
BA BSc (Hons) PhD
Seafood Services Japan