Ides of March: Ama Harvest Wakame (Seaweed)

Ama* – women of the sea – harvest shellfish and other seafood by diving into the sea. Awabi (abalone) and sazae (turban snails) provide their main source of income. However, many Ama also harvest seaweed. Seaweeds play an important role in Japanese cuisine and the retail market exceeds $1 billion annually. While many of these seaweeds are cultivated today, wild harvested seaweed earns premium prices.

Ama dive with the seasons. The Ama of Goza Town, on the tip of the Shima peninsula (Ise-Shima) finished the year diving for namako (sea cucumber, see earlier post). They remained on shore in January and February to avoid the cold waters of winter. They began diving again March 1 for wakame, Undaria pinnatifida, (Phaeophyceae, Laminariales) a leafy kelp used in soups and salads (Photos 1-3).


Photo 1: Wakame, Undaria pinnatifida, (Phaeophyceae, Laminariales) is a leafy kelp with a single large blade (the leaf-like portion) attached to a central stipe (stem-like portion). A holdfast (root-like portion) attaches the kelp to the rocky substrate. Strands of a thin-branched Sargassum sp, another type of brown alga, are interspersed among the wakame.

Wakame Being Harvested

Photo 2: Wakame being harvested by Yamashita-san. She holds two individuals by their stipe in her left hand; the holdfasts can be seen above her right hand. Note the broad, wavy stipe of the kelp in the lower right corner.


Photo 3: Wakame is commonly eaten in soups and salads. Here it is served as part of a nabe dish; foods are briefly cooked in a hot broth at the table.

Machiyo Yamashita-san, a master Ama diver in Goza, harvested wakame 10 days this March. We visited her on the morning of March 15, the last day of the harvest. We found Yamashita-san in her Ama Goya (hut), chatting with another Ama as they warmed themselves by the fire (Photo 4). Ama spend 30 minutes or more in their huts before diving, getting warm to the point of sweating. They don their wetsuits in the heat of the Ama Goya just before entering the cold ocean waters, 14.5o C (58o F) in March.

Ama Goya

Photo 4: Warming up before the dive in the Ama Goya. Mitsuko-san (far corner) is an Ama from Korea that has been diving with Yamashita-san for several years. Reiko has her back to the fire.

They took a short boat ride from the harbor to the dive site. En route, they de-fogged their masks using toothpaste, a modern replacement for the traditional leaves or seaweed still used by some Ama (see Ama Summit post). Once on site, each Ama put on her mask and fins, and quickly jumped overboard. They used a tanpo – a modified life preserver – to hold their catch and tools, and to provide support at the surface between dives (Photos 5-8).


Photo 5: Ama dive gear: a dive mask and toothpaste inside of a mask box, carried inside a bucket with a wet belt at the bottom. Toothpaste is used to de-fog the mask. Note the discoloration on the skirt of the mask, marks of age and use.

Photo 6: Ama gearing up at the dive site. After scrubbing the lens with toothpaste, the mask is rinsed. The breakwater of the harbor is visible in the background.

Entering From Boat

Photo 7: Mitsuko-san enters the water with kama (knife) in hand. Her yellow tanpo is already in the water. The tanpo is rigged with a net to hold her catch of wakame. It also provides a buoyant rest between dives.


Photo 8: Four tanpo and a bag of extra nets in the back of Yamashita-san’s truck, ready for the days diving. Each diver brought two tanpo (float with net) and extra nets. During the harvest, they filled one tanpo, brought it back to the boat, and traded it for their empty tanpo. The boatman (Sendo-san) processed the full tanpo while the Ama continued their work.

They immediately began diving for kelp. Surface dives were made headfirst with their feet and legs lifted out of the water (a pike dive). Each dive lasted approximately 30 seconds. Wakame was attached to the bottom by a holdfast, a root-like structure, at depths of 4-8 meters (13-26’). Each thallus** (the scientific term for the entire body of a seaweed) ranged in size from 1.5-2 meters tall (4.5-6.5’). Yamashita-san rapidly tore seaweed from the rocks, gathering a handful (6-12 thalli) before surfacing (see Photos 9-14).


Photo 9: Descent from the surface. A pike dive – bending at the waist (head down) and kicking legs vertically above the surface – provides gravitational force to propel the Ama’s descent.

Wakame on Bottom

Photo 10: Yamashita-san harvests wakame on the bottom. Note the central stipe (stem-like portion), large blade (leaf-like portion), and the tattered upper margin of the central wakame. The tattered portion will be cut off while processing the kelp on land.

Photo 11: Yamashita-san holds the harvested wakame by the stipe, between her fingers. Wakame provides food and habitat for many organisms. Note the filefish (kawahagi, Stephanolepis cirrhifer, upper right) that was hiding in the wakame.

Photo 12: Yamashita-san ascending with a handful of wakame. She holds the kelp by the stipe. Note the holdfasts with attached rocks.

Photo 13: Yamashita-san nears the surface. Her tanpo (foreground) is nearly full. Although Ama dive with weight belts, they are still relatively buoyant, and can passively ascend to the surface. The lower pressure near the surface allows the bubbles in their wetsuits to expand, which accelerates their rate of ascent.

Photo 14: Yamashita-san at the surface with her catch of wakame. She will place it into the net within the tanpo.

At the surface, Ama breath forcefully to effectively ventilate their lungs; some whistle or make ‘puu’ sounds. After 30-40 seconds at the surface, they dive again. Yamashita-san worked for almost two hours, from 9:45-11:30 a.m., making approximately 100 dives (see Video 1).

Initially, Yamashita-san harvested the entire thallus. Later, she used a kama – a small sickle-shaped knife – to cut the seaweed off at the holdfast. Although it took more time to harvest this way, it would save time later when preparing the seaweed for market (Photos 15-19).

Photo 15: Yamashita-san at the surface with her kama, a scythe-like knife. After harvesting a few tanpo filled with whole wakame, she retrieved her kama to harvest wakame without their holdfasts.

Photo 16a: Yamashita-san harvesting wakame with a kama.

Photo 16b: Yamashita-san harvesting wakame with a kama.

Photo 16c: Yamashita-san harvesting wakame with a kama.

Photo 17: Yamashita-san with a dozen wakame in hand, minus their holdfast.

Photo 18: Ascent with kama and wakame.

Photo 19: Yamashita-san trims wakame at the surface before securing her catch in the tanpo.

When diving for shellfish, an entire day’s catch can be carried within a single tanpo. Seaweed, however, is collected in bulk. Yamashita-san had to bring her tanpo back to the boat frequently to unload her catch. Typically, she brought a full tanpo and an extra handful of wakame on each trip to the boat. She handed her catch to Sendo-san (‘Mr. Boatman’). Sendo-san tossed in an empty tanpo ready to be filled, and secured the full tanpo (see Photos 20-24 and Video 2).

Photo 20: After filling her tanpo, Yamashita-san made a final dive for wakame before bringing her catch to the boat: a full tanpo plus a handful of wakame.

Photo 21: Transferring her handful of wakame to Sendo-san (the boatman).

Photo 22: Sendo-san with a handful of wakame.

Photo 23: An empty tanpo (yellow) has been tossed in by Sendo-san.

Tanpo in Boat

Photo 24a: The full tanpo is taken into the boat.

Photo 24b: The full tanpo is taken into the boat.

Photo 24c: The full tanpo is taken into the boat.

While the Ama continued to harvest wakame, the boatman emptied the full tanpo into another net bag, and closed up now the empty net of the tanpo (see Photos 25-27 and Video 3).

Photo 25: Wakame is released from the tanpo through a drawstring in the net, and dumped into a net bag.

Photo 26: The tanpo net is resealed for its next use.

Closing Net

Photo 27: Sendo-san closes a net bag used to carry the wakame on the boat and truck.

Reiko spoke with Sendo-san on the boat while I was in the water. His name is Tatsuhiro Iwamoto and he is the son of Yamashita-san’s cousin. He works as an Otoko Ama (male Ama) during the abalone season, but otherwise works as a tako (octopus) fisherman. One of his fellow tako fishermen came by to show Reiko his catch (Photo 28).

Photo 28: A nearby octopus fisherman came by to show us his tako (octopus).

On my previous dives with Yamashita-san I remained with her for the entire series of dives. However, the boat filled up with so much wakame that Sendo-san had to bring Reiko and I back to the harbor. He then returned to the dive site for the Ama and more wakame. The two Ama filled over 10 bags in less than two hours.

After the dive, Yamashita-san displayed her catch (Photo 29). She hung up whole wakame by their holdfasts to dry (Photos 30 and 31). The rest of the wakame was processed for immediate sale. A specialty store had ordered 150 kg (330 pounds) of fresh, wild wakame, which she bagged up after trimming (Photo 32).

Photo 29: Yamashita-san displayed some of her wakame at the beach.

Photo 30: Whole seaweeds were hung upside down by their holdfasts to dry.

Photo 31: Yamashita-san carrying a bag of wakame and her weight belt.

Weighing & Bagging

Photo 32: Weighing wakame for sale to a specialty market in Nagoya. They filled an order of 150 kg (330 pounds) of fresh wakame that day. The rest of their catch was sold locally, given to friends, and used for their own consumption.

Besides trimming the ends (holdfast and upper edges), she cut out the central ‘stipe’ – the stem-like portion of the thallus (see Photos 33 & 34). I was more familiar with the ‘blade’ (leaf-like portion) of wakame, used in soups and salads (see below). However, the stipe can be eaten as well. First, slice it into narrow strips. Second, add a bit of boiling water, then rapidly stir and agitate. The alginates in the kelp create a frothy sauce that is appreciated in Japanese cuisine; it was a little less inviting to my western sensibilities, but okay to eat (see Photos 35-38).

Photo 33: Yamashita-san describes how to process wakame. She gave one of these bags to us, and the other to a photographer friend (on right).

Photo 34: Trimming the blade from the stipe.

Photo 35: Chopping the stipe crosswise into thin strips.

Photo 36: Adding hot water (just boiled) to the chopped stipe turns the color to green.

Photo 37: After pouring off the hot water, Yamashita-san vigorously stirred the chopped stipe.

Photo 38: Fresh stipe of wakame, ready to serve!

Yamashita-san graciously sent us back to Kyoto with a large bag of fresh wakame and a bundle of dried wakame harvested two days before. We trimmed the fresh seaweed and cut the blades into smaller pieces, about 15 cm (6”) on each side. Tossing the blade into boiling water changed the kelp immediately from a golden brown to a bright green. A quick rinse in freshwater and it was ready to be served in either miso soup or a seaweed salad – good with vinegar or a sesame dressing (see Photos 39-41 and Video 4).

Whole Thallus

Photo 39a: Processing whole wakame at home in Kyoto; this photo shows a whole thallus.

Photo 39b: Processing whole wakame at home in Kyoto; this photo shows the removing of the holdfast.

39c: Processing whole wakame at home in Kyoto; this photo shows the removing of the blade from the stipe.

39d: Processing whole wakame at home in Kyoto; this photo shows cutting the blade into pieces. The removed stipe is at the lower part of the picture.

Raw Wakame

Photo 40a: Wakame can be eaten raw, but most people immerse it briefly in boiling water. This photo show a cut blade of raw wakame.

Photo 40b: Wakame placed in boiling water turns green in seconds.

Cooked Wakame

Photo 40c: A quick rinse in cool water and the wakame is ready for a salad or soup.

Salad & Soup

Photo 41: Dinner of wakame sunomono (vinegar salad) with cucumber and surimi (processed fish, aka ‘fake crab’), miso soup with tofu and wakame, and kare (sole).

We shared the fresh wakame with our family and neighbors. I was later able to share some of the dried wakame with my tea class teachers and classmates. It was much appreciated by all. Thank you Yamashita-san!

Wakame is the second most important seaweed in the Japanese diet, with recent annual harvests of 50,000-67,000 tonnes (data from 2010 and 2005, respectively). However, modern Japanese eat less seafood today than in the past, and the same is true of wakame. In 1976, Japan harvested 147,000 tonnes of wakame. At that time, wild wakame made up 13.6% of the total. In 2005 only 4.5% of the total was from wild wakame.

Wakame, like other kelp, prefers cool temperatures. They grow rapidly under the right conditions, but deteriorate in warmer waters. By late spring and early summer, the blades become degraded and essentially die back. Thus, they are an ideal catch for Ama at the start of the year. Moreover, their spores will give rise to new growth in the fall, which sustains the wild population.

Although we visited on the last day of the wakame harvest, these Ama were not ready for a holiday. The next day, March 16, was the opening for awabi (abalone) season, the most important catch of the year. For the first two days of the awabi season, the Ama of Goza and the Ama of Koshika, the neighboring town, will dive together along their shared border. In this way, they will avoid conflict with their neighbors.

Coming soon: more on seaweeds. We made our own nori using traditional methods in February, and we visited modern nori farms and factories throughout the growing season and the harvest. Hijiki – another wild seaweed – will be harvested at the lowest tide in April by many Ama villages. We plan to be there (Photo 42).

Photo 42: Drying out with the wakame after a long morning diving with Ama-san.

For more on Ama see these earlier posts:

Shirongo Matsuri: Ama Diver Festival

Season Opens for Lobster in Japan: Ama Dive

Ama Dive for Namako: Sea Cucumbers

** Seaweeds are not true plants. They lack stems, leaves and roots. Kelps are a group of brown algae (Phaeophyceae, Laminariales) that are relatively large and complex. Their body, or ‘thallus’, consists of a holdfast (root-like) for attachment to the bottom, a stipe (stem-like) that provides support for the main body, and a blade or blades (leaf-like) that make up most of the body of a kelp. Some kelp (but not wakame) have pneumatocysts (air-bladders) to keep their blades closer to the surface where the sunlight is most intense.

This entry was posted in Japan Sabbatical by Robert Reavis. Bookmark the permalink.

About Robert Reavis

I study fish behavior and marine ecology through direct observation while diving. I also teach General Biology, Marine Biology, SCUBA and Scientific Diving at Glendale Community College. This year (2011-2012) I will be in Japan to study Traditional Fisheries and Modern Environmentalism.

4 thoughts on “Ides of March: Ama Harvest Wakame (Seaweed)

  1. Pingback: Ama Harvest Hijiki: Ijika Town | Glendale Community College Blog

  2. Pingback: Nori – Japan’s Most Famous Seaweed: Part I, History and Traditional Use | Glendale Community College Blog

  3. I love to eat Wakame and now understand why it is not inexpensive. Real hard work goes into the business of finding, retrieving, processing and selling. I still love it and have a better appreciation for it. Old ex diver ed abel

  4. Ana and I love all of the pictures showing the steps from harvesting to eating. We finally understand a great deal more about wakame, which we love to eat, and why we have such a hard time finding certain parts of the wakame. Thank you! ❤

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s