Sea cucumbers as food

Lore & Background

Sea cucumbers destined for food are traditionally harvested by hand from small watercraft, a process called 'trepanging' after the Indonesian Malay word for sea cucumber teripang. They are dried for preservation, and must be rehydrated by boiling and soaking in water for several days. They are mainly used as an ingredient in Chinese cuisine soups and stews. From the 17th or 18th century CE onwards, traders from Sulawesi established extensive seasonal trade links with the Indigenous peoples of the Kimberley region, the modern-day Northern Territory, and Arnhem Land, collecting trepang to supply markets in Southern China. In Japan, sea cucumber is also eaten raw, as sashimi or sunomono, and its intestine is also eaten as konowata, which is salted and fermented food. The dried ovary of sea cucumber is also eaten, called konoko or kuchiko. It is also considered a delicacy in the northwestern Mediterranean, particularly in Catalan cuisine, often as an ingredient in rice dishes.

Reader's Guide

Both a fresh form and a dried form are used for cooking, though its preparation is complex due to its taste being entirely 'tasteless and bland'. The Suiyuan shidan, the Chinese Qing Dynasty manual of gastronomy, states: 'As an ingredient, sea cucumbers have little to no taste, are full of sand, and are fishy in smell. For these reasons, it is also the most difficult ingredient to prepare well.' Much of the preparation goes into cleaning and boiling it, then stewing it in meat broths and extracts to infuse each sea cucumber with flavour. In Chinese medicine, sea cucumber is considered useful for treating tendonitis and arthritis, along with functioning as an aphrodisiac. Gamat has been traditionally used by Malays for wound healing, painkilling, and the treatment of stomach ulcers. Studies have found that sea cucumber possesses anti-diabetic and antioxidant properties. Following campaigns encouraging people to avoid shark fin soup, sea cucumber has become an increasingly popular replacement in China. Many sea cucumber species are endangered from overfishing due to the food industry's demand for their consumption.

Did You Know?

• Sea cucumbers are known as bêche-de-mer in French, from Portuguese bicho do mar (lit. 'sea animal').
• The Asian market for sea cucumber is estimated to be US$60 million.
• In Japan, the dried ovary of sea cucumber is eaten as konoko or kuchiko.
• Sea cucumbers are considered non-kosher in Jewish dietary law since they lack scales.

A Delicacy Across Cultures

Sea cucumbers hold a distinctive position in the global culinary landscape, celebrated as a delicacy seafood with particular prominence in Asian cooking traditions. The harvested product goes by a remarkable array of names—trepang, namako, bêche-de-mer, balate—each reflecting a different regional food culture that has adopted this marine creature into its cuisine. Supply for sea cucumber as food runs along two parallel tracks. In many coastal communities, people still forage wild populations directly from the sea floor. Simultaneously, a growing number of species are now raised in controlled aquaculture systems for commercial harvest. This combination of wild collection and farming mirrors how other prized seafoods have been sourced throughout history. Biologically, these animals are echinoderms of the class Holothuroidea, distant relatives of starfish and sea urchins. Yet on the plate or in the market, they present as a soft, leathery, elongated body whose loose resemblance to the cucumber fruit is the very feature that gave the group its common name.

A Vast and Varied Fauna

Approximately 1,786 species of sea cucumber have been formally described, and they inhabit sea floors around the entire globe. The single richest region for holothuroid diversity is the Asia–Pacific, where the greatest concentration of species occurs. The physical forms of these animals are astonishingly varied. Most measure between 10 and 30 centimetres in length, but the extremes stretch far beyond that range. The smallest known species, Rhabdomolgus ruber, is only a few millimetres long, while Synapta maculata can exceed three metres. In the Americas, Holothuria floridana is the largest species, reaching 25 to 30 centimetres and holding a volume well over 500 cubic centimetres as it abounds just below the low-water mark on Florida reefs. Shape adds further diversity: some species are nearly spherical and earn the nickname "sea apples" (genus Pseudocolochirus), others are serpent-like (order Apodida), and still others take on a classic sausage or caterpillar profile. This morphological range is unusual even among echinoderms, most of which display the familiar five-armed star shape.

Engineers of the Seafloor

Beyond their role as a food source, sea cucumbers perform a critical ecological function on the seafloor. As detritivores, they feed on dead organic matter and other detritus that settles on the ocean bottom. By consuming and processing this material, they initiate a key step in nutrient recycling: the organic matter they break down is subsequently made available to microbial communities, which carry the decomposition process further along the chain. This role positions sea cucumbers as essential engineers of benthic ecosystems. Without their constant grazing and processing of organic debris, nutrient cycling on the sea floor would slow considerably, affecting the broader web of marine life that depends on those recycled nutrients. Their body plan is well suited to this work. The mouth, located at the anterior end, is encircled by a crown of tentacles—highly modified tube feet—that can be extended to gather particles and then retracted back inside the animal. The anus sits at the opposite, posterior-dorsal end, completing a simple but effective through-gut system adapted for continuous processing of seafloor detritus.

The Remarkable Catch-Collagen Body

One of the most extraordinary features of sea cucumbers is the specialized collagen in their body wall, often called "catch" collagen. This protein network can be actively loosened or tightened at the animal's will. When a sea cucumber needs to squeeze through a narrow crevice or crack, it relaxes its collagen fibres, essentially softening its body to a near-liquid state so it can pour itself into the gap. Once safely inside the shelter, it re-engages the collagen, hooking the fibres back together to restore full rigidity. This mechanism gives the animal a flexibility that few other echinoderms possess. At first glance, a sea cucumber looks almost unlike its starfish and urchin relatives: it has a soft, cylindrical body with no visible external skeleton and no hard appendages. Its internal skeleton is reduced to isolated microscopic ossicles joined by connective tissue, and in some abyssal or pelagic species—such as Pelagothuria natatrix—the calcified skeleton is absent entirely. Despite this softness, the animal maintains a subtle fivefold symmetry inherited from its echinoderm ancestry, overlaid with a bilateral symmetry that makes it appear, at a glance, almost chordate-like.