SEAWEED AS A FOOD

100.     For some thousands of years seaweeds have been highly valued and widely consumed as a direct human food by oriental communities. In the West no such tastes or traditions have been acquired. The Greeks and Romans had little regard for seaweeds and the use of algae as a specific food item was, in general, discontinued in Europe and North America in the course of the last century.

101.     Before examining the long-established and still expanding markets for edible seaweeds in the East, particularly in Japan, their use in other parts of the world will first briefly be examined.³

³ For comments upon the nutritional value of seaweed see pages 42–43

102.     In Europe, human consumption of fresh or lightly treated seaweeds appears to have withered away as standards of living have risen. Young stipes of Laminaria saccharina used to be sold in street markets in Scotland as “tangle”, and dulse (Rhodymenia spp.) was a significant food item in Ireland for many centuries. In Brittany, a form of jellied-bread, “pain des algues”, was once regularly prepared from Laminaria and Chondrus spp. A similar “laver-bread”, using the species Porphyra, is still eaten in certain parts of South Wales but recent levels of consumption are said (Booth, 1964) not to have exceeded 200 tons per year. Another example of continuing, if now minor, use of edible seaweeds is in Iceland where Rhodymenia palmata, locally known as “söl”, and species of Alaria, Chondrus and Gigartina have traditionally been valued as palatable, nourishing foods with therapeutic side benefits (Hallsen, 1964).

103.     Rhodymenia is also still consumed in parts of North America, where it grows in abundance off the Maritime Provinces of Canada. Several hundred thousand tons are harvested annually and, after natural drying, are sold as dulse for use as a relish on meat and fish dishes. On the Pacific coast of North America, the stipes and bladders of the giant brown seaweed Nereocystis luetkeana are marketed locally in desalted, flavoured and candied pieces as “seatron”, and used as a confectionery and speciality food product (Levring, Hoppe and Schmid, 1969). In the Caribbean, various species of seaweed are used to prepare jellies. On the island of Grenada, for example, Idyll (1970) noted the drying and bleaching of Gracilaria for use as a kind of porridge. The use of seaweeds, notably Laminaria or “sea cabbage”, as food in the U.S.S.R. was reported by Barbaianow (1959).

104.     The green seaweed, Ulva, a ubiquitous genus found in marine and brackish waters, is eaten - generally fresh - in many parts of the world; it is frequently referred to as “sea lettuce”. Its use as a salad, as a vegetable and as a soup ingredient is reported in places as widespread as Scotland, the southwest coast of North America, India, Siberia and the Pacific coast of South America as well as many parts of southeast Asia. It is said to be particularly valued by the natives of Chile, where it is known as “luche”; consumed even more widely in Chile is the stipe of the giant bull kelp, Durvillea antarctica, which is washed and dried and sold as “cochayuyo” for use mainly as an admixture in thick soups.

105.     On the continent of Africa, seaweed appears to be largely neglected as a direct source of food. Chapman (1970) refers to the traditional employment of Suhria vittata, known along the South African coast as “red ribbon”, for jelly-making by the early Cape colonists. An interesting occurrence is the use of the blue-green, freshwater algae Spirulina, as a food in Chad. This weed is particularly rich in vitamins and has been long valued by central African tribesmen as a weaning food for infant children and for making biscuits and meals in conjunction with millet; the algae grows on the surface of ponds and pools and it is reported that annual yields of up to 50 tons per hectare can be obtained.¹

¹ FAO, Press Release, SF/54 - MI 80932

106.     In many parts of the Indo-Pacific region, however, seaweeds are highly regarded as a human food. In a review of the marine algae of tropical south and east Asia, Zaneveld (1955) described the characteristics, distribution and utilization of a very large number of individual species. Although observing that in the region the use of marine algae as food, particularly in the Malay peninsula and in Indonesia, now seems to be by no means as general as one would have supposed from earlier authors, Zaneveld nevertheless presents an extensive list of continuing instances of such consumption.

107.     Species of the green seaweed, Caulerpa, for example, are eaten raw or cooked, as salads or desserts, in The Philippines, Malaysia, Guam, Celebes, Bali, Singapore and Sri Lanka; a number of brown seaweeds, such as Sargassum and Turbinaria, are consumed fresh, cooked in coconut milk or smoked-dried in Polynesia, China, Japan, The Philippines, the Moluccas, Malaysia and Hawaii. Red seaweeds, notably Porphyra, Gracilaria, Laurencia and Rhodymenia, are even more widely used for human food in many parts of the region. The islands of Hawaii present a particularly interesting example of the role of seaweeds as a human food. A very large number of algae, collectively called “limu”, have traditionally occupied an important, and once staple, place in local diets. The algae are not usually eaten separately but chopped into fine pieces (either fresh, soaked or boiled) for use in combination with other foods. The strong spicy flavour of “limu-fua fua”, the species Caulerpa clavifera, gives it an especial value as a relish; “limu-kala” (Sargassum spp.) is used in fish and meat dishes; Porphyra, known locally as “limu luan”, occurs in such relatively small quantities that it is regarded as a particularly choice delicacy, once served only to nobility. Even in Hawaii, however, these long-standing traditions are weakening and with the advent of abundant western-style food, seaweed eating in the islands is now becoming reserved primarily for special occasions.²

² Chapman (1970)

Fig. 17 Gigartina stellata (R)	Fig. 18 Pterocladia pinnata (R)
Fig. 19 Ulva sp. (Gr) “Sea lettuce”	Fig. 20 Caulerpa sp. (Gr)

Table VIII

Japan: Consumption of Main Edible Seaweeds 1963–1973

Source: Annual Report on Family Income and Expenditure Survey, 1973, Bureau of Statistics, Office of Prime Minister, Tokyo

^a Data not available. A review of the production data indicates that average household consumption of “nori” in 1973 was of the order of 800 g per annum, compared with 400–450 g ten years previously

^b Data not available. Other information indicates that “nori” prices are more than double those of “wakame” and “kombu” but have risen at a less rapid rate

Table IX

Japan: Production of Main Edible Seaweeds 1963–1974

Source: Annual Reports of Ministry of Agriculture and Forestry, Tokyo

^a for “nori”

^b for “wakame”

^c for “kombu”

108.     In Japan no such decline is apparent in the traditionally high and diverse consumption of edible algae. Annual consumption of the three main seaweed food products eaten in Japan - “nori”, “wakame” and “kombu” - reached an average of some 3.5 kg per household in 1973, an increase of about one fifth compared with ten years previously, notwithstanding a rapid rise in retail prices over the period (see Table VIII). Taking into account various other minor seaweed foods, annual consumption of edible seaweeds in Japan averaged approximately one kilogramme per person, a remarkably high figure for such paper-light food items used primarily as an additive or garnish to more bulky dishes. Together these seaweed foods represent a very important industry in Japan, with a value now amounting to some U.S.$ 700 million per annum, far in excess of the value of total world output of phycocolloids.

109.     Japan's production of edible seaweeds has been of the order of 600 000 tons (wet weight) in recent years, nearly double that of the early 1960s (see Table IX). Supplies from natural resources have been increasingly supplemented by cultivated weeds, in particular Porphyra and more recently Undaria. The techniques and potential of seaweed cultivation are examined in a later part of this paper; at this point it is sufficient to note that in 1973–74 about three quarters of total Japanese supplies of edible seaweeds were cultivated.

110.     The most important edible seaweed product consumed in Japan, “nori” - derived almost entirely from cultured Porphyra - is marketed in thin, uniformly sized, sheets of dried and pressed weed; it has many uses in a variety of traditional dishes, including “sushi”, the popular rice and fish balls. “Kombu”, prepared from compressed Laminaria, is sold in many forms - shredded, powdered, seasoned, roasted and sugared - and is widely used as a soup stock, as a vegetable and, after soaking in soy sauce, with rice dishes. The other principal edible seaweed product, “wakame”, is obtained fairly simply by washing and drying Undaria; it is marketed mainly in a desalted form and eaten chiefly with soybean soup. These, and other minor seaweed products eaten in Japan, are more fully described in Appendix III.

111.     Edible seaweeds are commonly consumed in other countries bordering the Sea of Japan and the Yellow Sea. In the Republic of Korea, whilst much of the production is exported to Japan, cultured Porphyra is used to prepare a laver product of very high quality which is enjoying rising demand on the domestic market; Hizikia fusiforme, various species of Ecklonia and a number of green algae are also consumed in Korea, dried or as a fresh vegetable. In China, some 100 000 tons of Laminaria are said to be cultivated annually for direct consumption¹ and considerable quantities of the dried weed are imported from Japan. Chapman (1970) listed over twenty algae or their products eaten in China. Laminaria species are also reported to be utilized for “kombu”-type products in Sakhalin and other parts of the Pacific coastlien of the U.S.S.R. (Levring, Hoppe and Schmid, 1969).

¹ Tseng and Wu (1962)