“If things carry on the way they are, every single pole-and-line fisherman in Ōma will be out of work next year,” said Mr. Minami whose family has been in Ōma’s pole-and-line fishing trade for generations.

“This might be the first time in over 30 years, back in the year when the Seikan Tunnel was constructed, that landings have been so low.”

These were the first words that came out of his mouth and they reveal how exceptionally poor tuna catch has been in recent years. 
Rising sea temperatures due to global warming is claimed to be one of the reasons behind the poor catches as it has caused sudden drops in the number of squid, which is a food source for tuna. But the fishermen think that is not the sole cause.

Another factor that can be considered is the practice of overfishing which is still rampant in Japanese waters. This style of fishing gives no thought to fishing seasons and captures everything from spawning tuna to juvenile fish.

“Large vessels catch what a pole-and-line fisherman from Ōma catches in a year, in just one day.”

Tuna that has been caught by fishing methods that solely focus on volume is not necessarily of a high quality. They may struggle in the net for hours which causes their body temperature to rise resulting in “burnt” tuna, or they may be hauled in with wounds to their body caused by the other fish.

On the other hand, the traditional pole-and-line fishing method practiced in Ōma involves catching tuna one at a time using a single monofilament fishing line and spiking the fish on board.

“Each tuna is handled carefully which helps maintain its high quality for longer. How you spike the fish is extremely crucial in maintaining the quality of the fish.”

“But recently, tuna gets priced pretty well no matter the quality just because there’s less and less going out on the market,” says Mr. Nitta who has been determining the quality of Ōma tuna day in and day out as a merchant for years.

Overfishing occasions a fall in supply, and as a result, it continues to give way to a framework that favors those with a bigger catch rather than one that focuses on the actual quality of the fish. Both men believe that the true challenge is in overcoming this vicious cycle which is putting fishermen in an even more precarious position.

That afternoon, the development team hastily made their way to a port in Ōma after receiving news that it had just had a Pacific bluefin tuna landing for the first time in precisely a week.

Using TUNA SCOPE, we tried inspecting the quality of the fish from the cross section of its tail. Up until then, TUNA SCOPE had been acquiring the inspection skill from data on yellowfin tuna tails making Pacific bluefin tuna tail inspections an unchartered territory. Although it was only a provisional attempt, the tuna was given an A - the highest grade. Mr. Nitta who was watching on, could not help but break into a smile.

“When quality inspections are conducted by humans, sometimes there’s the unavoidable temptation to adjust the figures so it evens out with the supply and demand. But AI doesn’t get influenced by such factors so it can make fair and impartial judgements.”

As AI-based quality inspections are impartial to the circumstances surrounding both the seller and the buyer, they have the potential to become the new evaluation criteria for the tuna trade.

The following evening, Mr. Minami received a phone call from his son during the interview.

“I’ve been thinking about it a lot, and I want to follow in your footsteps and become a fisherman.”

“Deep down, I’m really pleased, but it’s hard to be genuinely happy about it given the current situation of the Ōma fishing industry,”he said.

“If we can be recognized for catching tuna that tastes great, we might start seeing some gradual changes in the market situation,”both Mr. Minami and Mr. Nitta observed after seeing firsthand quality inspections conducted by TUNA SCOPE.

From quantity to quality: changing the standard of the tuna trade

To this day, it is not uncommon for tuna to be traded by gross volume and distributed to the global market without undergoing proper quality inspections. The widespread use of TUNA SCOPE may help ensure that all tuna undergoes proper quality inspections and that fish caught by conscientious methods fetches higher prices at markets.

In the future, our AI system may transform the dynamics of business and result in protecting our precious resources on a global scale. Talking to the fishermen of Ōma and our stay in the town made us realize the true potential of TUNA SCOPE.