Nori Harvest in the Ariake Sea

When it comes to artisanal Japanese ingredients, one theme sure is consistent: it takes an enormous amount of work to create these products. This was proven to us again in February 2024 when we visited the Ariake Sea to see the nori harvest.

It takes quite a while and numerous trains, including a long stint on the Shinkansen (bullet train), to get from Tokyo to the city of Saga down in Kyushu. It was here that we met up with Nagahara-san of Motoi Nori as well as our exporter, sesame producer, and friend Takehiro Wada of Wadaman. A 20-minute drive from our hotel brought us to the shores of the Ariake Sea where we met up with a local nori farmer. After donning life vests, we hopped onto his boat and were taken down the Hayatsue River. Where the river empties into the Ariake Sea, we saw what seemed to be endless rows of poles sticking out of the water. These were the nori farms, lying just off the coast in relatively shallow water. Nagahara-san started telling us the story of nori.

Although people in Japan have been eating nori for over 1,300 years, the farming of nori only started about 80 years ago. Since then, the Ariake Sea has become the biggest production area in Japan. Because it is fed by multiple rivers and has a large tidal change (the tide rises and falls a total of 6 meters - almost 20 feet), the Ariake Sea is ideally suited for nori farming and produces very high-quality nori.

The nori calendar, so to speak, starts in August, when the local nori union decides which farmers will get which “plots” in the local waters (see image). When you’re on the water, it really does look like the nori farming goes on as far as the eye can see, but the farms are actually kept in the relatively shallow waters near the coastline.

The next step comes in September, when each farmer will put long poles in the water. These poles, set up in a grid pattern, are 7-8 meters (23-26 feet) long and are embedded about 1.5-2 meters (5-6.5 feet) into the seabed. Then, in October, the farmers tie nets that they have seeded with nori to these poles. Picture a smaller version of a net that sits under a trapeze artist and you get the idea of the set up. As mentioned above, there is a large difference between the water level of the high and low tides. This means that at low tide, these nets are completely out of the water, basking in the sun which makes the nori sweeter and softer. And during high tide they are deep below the surface, taking in nutrients.

The first harvest happens by the end of December. This first harvest is highly sought after similar to how Beaujolais Nouveau is celebrated. Like Beaujolais Nouveau, it isn’t actually the highest quality. The highest quality nori comes in the middle of the harvest season in January and February. By the end of the season in March, the quality of the nori declines, with the color becoming lighter (less desirable).

Fun fact #1: nori farmers are also shellfish farmers…they ‘grow’ these shellfish under the nori. The shellfish help clean the water. The shellfish harvest starts after the nori harvest.

When it is time to harvest nori, the fishermen come out in their flat-bottomed boats only during the two hours on either side of each night’s high tide. The boats are positioned between the rows of poles and the nori nets are rolled onto a special machine on the boat. As the net is rolled onto the machine, the nori is cut off. When his boat is full, the farmer takes his boat back to the shore where the nori is pumped into either a waiting small tanker truck or directly into the processing facility.

Fun fact #2: ducks are the bane of a nori farmer’s existence, since they love to eat the nori.

After our time on the water, we visited a processing facility. Perhaps using the word “facility” makes it sound like a giant factory, but there are numerous small processing facilities in the area. The one we visited was perhaps 1,000 square feet in size.

The nori is mixed with sea water to keep it fresh for the next few steps. First it is cleaned twice and then put into a cutting machine. The cutting step changes a bit as the season progresses. Earlier harvests yield a softer nori, so the cutting disk has larger holes. Later harvests yield harder nori, so the cutting disk has smaller holes.

After cutting, the nori is now mixed with fresh water and air to maintain freshness. The cut nori is then pumped up into a machine that has a wide conveyor belt consisting of numerous plates that look similar to sushi rolling mats. The cut nori is then deposited on these mats, which are the standard size of a full sheet of nori – 19cm x 21cm (about 7.5” x 8.25”). A sponge is used to remove excess moisture and then the conveyor belt moves the nori-covered mats into a drying machine where they spend about 3 hours at between 30 and 40 degrees C (86-104 degrees F).

Fun fact #3: nori’s familiar square shape was standardized during the Edo period (1603-1868).

At this point the nori is graded, packed and shipped off to auction. It is during the auction season, which runs from December to April, that Motoi Nori employs their expertise to supply us with the best quality nori. Nori grading, in contrast to the very strict konbu grading, is meant to only be a guide for the purchasers. There are numerous auctions during the season, and the lot sizes range from small to large. Because of this, the buyers must employ their skill and experience to gauge the quality of the nori, looking at color, texture, luster, aroma and whether it has any holes. This buying step is so important, the CEO of Motoi Nori attends many auctions. We are fortunate that Motoi Nori only provides us with nori from the early (but not first!) harvests.

Once the nori gets to Motoi Nori’s facility in Osaka, it is dried again and then, right before shipping, roasted to the customer’s specification. This roasting process helps to highlight the natural flavor of the nori.

As with the konbu harvest that we witnessed in 2023, we have come to realize the immense amount of work that it takes to get that sheet of nori to your table. Like all farming, so many things need to be in delicate balance to have a good outcome. You need rain, but not too much, to get nutrient run-off from the mountains and land to provide nutrition to the nori fields. Typhoons? A direct hit can be bad, but a glancing blow, that can be good.

Unfortunately, things have not been in that delicate balance. Climate change has altered the water temperature, which has altered the nori season. Warmer water means the time when nori ‘fields’ are sown has been delayed from early October to late October. And the harvest ends earlier now – March vs April. In all, it means they have lost a harvest or two.

The number of nori farmers is also decreasing, which limits the amount of nori that can be harvested. And with increasing prices and changing diets of the Japanese, domestic demand has faltered.

Nori harvests in the Ariake Sea have dropped from 2.2 billion sheets in 2010 to around 1.7 billion recently, about a 23% decline.

But not all is grim. The community of nori farmers around the Ariake Sea is strong. There is much research and development work being done with regards to nori seedling varieties, as well as work in the area of automation. We are thankful for the work of the nori farmers and our friends at Motoi Nori that allows us to offer you such high-quality nori.

Fun fact #4: we were rewarded at the end of the day with nori soft cream (soft serve ice cream). Yes, it was delicious.