The Japanese Sea Cucumber Market: Iriko, Ama Divers, and the World's Leading Exporter

In the year 927 A.D., a book of laws and regulations called Engishiki was compiled in the imperial court of Heian-kyo, the city now known as Kyoto. Among the tributes that provincial governors were required to deliver to the imperial court and to Shinto shrines, the document listed iriko, the dried sea cucumber, as an item of sufficient value to be demanded alongside rice, silk, and other commodities of the highest importance. That reference, over eleven centuries old, is among the earliest documented evidence of a market for dried sea cucumber anywhere in the world.

Since the eighth century, the people of Noto in present-day Ishikawa Prefecture, Oki in Shimane Prefecture, and Shima in Mie Prefecture delivered iriko as tribute. The book of laws and regulations Engishiki, compiled in 927 A.D., mentioned iriko as a tribute. There being no way of preserving sea cucumbers except in the dried form, iriko probably explains why it became a tribute for noble families and Shinto shrines.

Japan's relationship with sea cucumber is the oldest documented commercial relationship with this animal in the historical record. Understanding how that relationship evolved, and how the Japanese market functions today, reveals a market that is structurally different from China and Hong Kong in almost every dimension that matters for supply chain decision-making.

The Linguistic Foundation: Namako, Iriko, and What the Words Reveal

In Japan, sea cucumbers or holothurians are generally known as namako. Strictly speaking, namako refers to fresh or live sea cucumbers, while the dried form is called iriko. Etymologically, the word nama in Japanese means fresh, thus namako refers to fresh or live ko. The meaning of the Japanese word iri is for the boiled or desiccated product, and iriko thus refers to dried ko. Fermented intestine of sea cucumber prepared for human consumption is called konowata, meaning sea cucumber intestine.

This linguistic precision, documented in the academic literature on Japanese sea cucumber foodways, reflects a broader characteristic of Japanese market convention. Where Chinese trade terminology uses a single term, hai-som, to encompass both fresh and dried forms, Japanese terminology distinguishes them with separate words that carry distinct cultural and commercial associations. This precision extends to how the Japanese market evaluates, prices, and consumes sea cucumber at every level of the supply chain.

The Ama Tradition: Female Free Divers and Centuries of Harvesting Knowledge

Japan's domestic sea cucumber harvest has been conducted for centuries through a harvesting tradition that has no parallel in the global beche-de-mer trade. In Japan and Korea, sea cucumbers have historically been caught by female free divers known as ama and haenyeo respectively. The ama divers of Japan's coastal communities, concentrated particularly along the Noto Peninsula in Ishikawa Prefecture and the Shima Peninsula in Mie Prefecture, developed their harvesting techniques across generations in which marine resource knowledge was transmitted from mother to daughter.

The ama tradition is not primarily a labor arrangement. It is an ecological management system. Female divers who harvest the same reef areas across a lifetime develop an intimate knowledge of species population dynamics, reproductive cycles, and the harvesting intensities that specific areas can sustain without long-term depletion. This knowledge, accumulated over generations and embedded in community harvesting practice, represents a form of traditional ecological knowledge that has been documented in Japanese fisheries research as a significant factor in the relative health of ama-harvested populations compared to mechanically harvested fisheries.

The ama diving tradition has declined dramatically over the past half century due to aging populations in coastal fishing communities and the migration of younger generations to urban employment. The number of active ama divers in Japan has fallen from an estimated 40,000 in the mid-20th century to fewer than 2,000 today. This demographic decline has direct supply implications for Japan's domestic fresh sea cucumber market, contributing to the sustained price appreciation of fresh namako in Japanese retail and restaurant markets.

Japan as the World's Leading Sea Cucumber Exporter

The 2026 study by Conand, Cornet, and Lovatelli in the Journal of the Marine Biological Association of the United Kingdom documents a finding that surprises many participants in the global sea cucumber trade: Japan is the leading exporter by value in global sea cucumber trade, a position reached through the combination of high-value domestic production and active re-export of processed product to Chinese markets.

Japan's position as the leading exporter by value reflects a specific commercial logic. Japanese processors apply processing standards and quality control to Apostichopus japonicus that command premium prices in Chinese retail markets. The Japanese sea cucumber, processed to iriko by established operators in Hokkaido and other northern production areas, is recognized by Chinese premium buyers as distinct from the iriko produced in Russia or Korea from the same species. Processing quality, packaging standards, and the commercial reputation of Japanese-origin product collectively command a price premium that translates into export value leadership despite Japan's production volume being lower than China's aquaculture output of the same species.

Apostichopus japonicus: The Species That Defines the Japanese Market

Apostichopus japonicus is the primary species consumed in Japan, and it is a seasonal delicacy eaten mainly in winter, especially during the winter solstice and the New Year. It can be enjoyed at home, but is often consumed in restaurants or Japanese-style bars called izakaya. This seasonality distinguishes the Japanese consumption pattern from Chinese consumption, where dried sea cucumber is available and consumed year-round as a premium ingredient with no specific seasonal association.

The seasonal concentration of namako consumption in Japan creates specific demand dynamics. The winter harvest season for wild A. japonicus in Japanese waters, primarily conducted by ama divers in Ishikawa, Mie, and Shimane Prefectures along with mechanized harvesting in Hokkaido, aligns with the peak consumption window. Fresh namako commands its highest prices in December and January, when New Year celebration demand peaks and domestic supply is at its most active.

The main sea cucumber species in Japan are Apostichopus japonicus as the most appreciated and consumed, with two additional species Parastichopus nigripunctatus (okiko) and Cucumaria japonica (kinko) commercially harvested in small volumes. For supply chain operators considering Japan as a destination market for Indonesian tropical species, this species hierarchy is a critical commercial reality. Indonesian species such as Holothuria scabra, Thelenota ananas, and Holothuria fuscogilva occupy a specific and limited niche in the Japanese market, rather than competing for the mainstream position held by A. japonicus.

The Japanese Market for Tropical Species: Opportunities and Constraints

The Japanese market's strong orientation toward Apostichopus japonicus does not mean tropical Indonesian species are absent from Japanese trade. Several tropical species, including Holothuria scabra, Stichopus chloronotus, and Thelenota ananas, appear in Japanese trade records and in the inventories of specialist importers. But the commercial context is fundamentally different from the Chinese market.

In Chinese markets, tropical Indo-Pacific species including Indonesian sandfish and teatfish are among the most prestigious products in the entire dried seafood category. In Japanese markets, they occupy a secondary position, consumed by a specific subset of buyers familiar with their culinary properties and willing to pay premium prices for authentic Indonesian-origin product. The Japanese buyers who source Indonesian sea cucumber tend to be more technically sophisticated than Chinese buyers operating at the same price point, because they are operating outside the mainstream of Japanese sea cucumber consumption and require specific knowledge of tropical species culinary applications.

For Indonesian exporters, this market characteristic means that Japan is not a high-volume destination for tropical species but can be a high-value one. The premium that knowledgeable Japanese buyers pay for verified, species-specific, well-processed Indonesian iriko reflects a different value calculus than the Chinese market, where premium is driven by species prestige and size. In Japan, the premium is driven by processing quality, documentation authenticity, and the culinary properties of the specific product in the hands of an informed buyer.

Japan as a Re-Export Hub for Tropical Sea Cucumber

Beyond direct consumption, Japan plays a specific role in the global beche-de-mer trade as a processing and re-export hub for tropical species destined for Chinese markets. Japanese processors with access to tropical sea cucumber from Southeast Asian suppliers apply Japanese processing standards to produce iriko that commands premium prices in Chinese retail markets. The Japan-origin labeling adds commercial value to tropical species through the association with Japanese processing quality, in the same way that Hong Kong grading and redistribution adds value through the authority of the world's most sophisticated quality evaluation system.

This re-export function creates a specific type of supply chain relationship that Indonesian exporters can access: supplying semi-processed or processed tropical sea cucumber to Japanese processors who complete the processing to Japanese standards before re-exporting to Chinese markets. For Indonesian operators with the processing capability to meet Japanese import standards, this pathway offers access to Chinese premium market prices through Japanese commercial networks that already have the buyer relationships and documentation infrastructure in place.

Import Requirements for Sea Cucumber into Japan

Japan's food safety regulatory framework for imported seafood is administered by the Ministry of Health, Labour and Welfare (MHLW). Dried sea cucumber imported for food use is subject to Japan's Food Sanitation Act, which requires that imported products meet Japanese standards for contaminants, additives, and microbiological safety.

For CITES-listed tropical sea cucumber species, the standard CITES export permit from the Indonesian Management Authority is required at Japanese customs clearance. Japan is a CITES signatory and enforces Appendix II permit requirements at the border. Indonesian exporters supplying Japan with Holothuria scabra, any Thelenota species, or white or black teatfish must ensure that their CITES permits are valid, batch-specific, and presented at the point of import.

The Japanese market does not currently have a facility registration requirement comparable to China's GACC registration for seafood processing facilities. However, importers are responsible for ensuring that their Indonesian suppliers meet Japanese food safety standards, and Japanese import agents typically conduct or commission facility audits of new suppliers before establishing commercial relationships.

__________________________________________________________________________________________

Sepanjang — Indonesia's Specialty Ocean Products Co. Sourcing high-quality sea cucumber directly from Indonesian waters for over 20 years.

PT Sepanjang Laut Nusantara is an Indonesia's Specialty Ocean Products Co. specializing in Sea Cucumber, Seaweed, Abalone, and Seashell from Indonesia — for domestic and international B2B markets.

SEPANJANG

PRODUCT

Sea Cucumbers
Seaweed
Abalone
Seashell

© 2025 PT Sepanjang Laut Nusantara. All rights reserved.