Vegetables from the sea Just as in many other parts of the world, seaweeds found cast up on Western Australian beaches can provide a tasty treat. by John Huisman

e often regard seaweed as these seaweeds are valuable, generating As well as the species eaten directly, Wsomething to avoid. It collects billions of dollars each year. many seaweeds are used to make in huge smelly piles on the beach, Seaweeds have been a staple part desserts. This is possible because the or slithers around the ankles during of Japanese and Chinese diets since cell walls of these seaweeds produce a paddle in the shallows, generally prehistoric times. As far back as 600 compounds known as colloids, which making that trip to the seashore a BC, Sze Teu wrote in China ‘Some can be extracted and will set at room less pleasurable experience. Sure, it algae are a delicacy fit for the most temperature. The Western Australian is essential for the wellbeing of the honoured guests, even for the King jelly weed (Betaphycus speciosum) is one coastal ecosystem, but what possible himself’. Presently some 21 species are of the few examples of local seaweeds direct value might there be to people? eaten in Japan, where they account for with a history of human use. In the Surprisingly to most, that value is about 10 per cent of the Japanese diet. early days of the Swan River Colony, immense and varied. Some 400 different Seaweeds are also eaten in other parts beach cast plants of this seaweed would species of seaweeds around the world of Asia, in Europe and in several places be collected and used to make jellies are used by people for food, stock feed, in the tropical Pacific. In the Hawaiian or blancmanges. Plants are cleaned and medicines, fertilisers, and to provide Islands, edible seaweeds (known as bleached in the sun, roughly chopped raw materials for food processing and limu) are an important part of the local and then simmered in milk for about numerous industrial processes. And cuisine and have been for centuries. 30 minutes. Once the mixture starts to thicken it is strained to remove the seaweed (which is discarded), flavoured, and then allowed to set in the fridge or at room temperature. Relative to other nationalities, Australians are newcomers when it comes to eating seaweeds, but our recent enthusiastic adoption of Asian cuisine is resulting in a broadening of tastes to include these marine vegetables. virtually on our doorstep. With a well as being used as the familiar The thought of eating sushi rolls little encouragement and a taste for wrapping around sushi rolls (more wrapped in seaweed would have been experimentation, it should be possible accurately called sushi maki), nori is incomprehensible to most Australians for Western Australian seaweeds to also used to flavour a wide variety of snack of 50 years ago, but today these exotic find a place at the dinner table! foods. Nori is sold in sheets that may foods are widely available and are Only a few seaweeds have an be toasted to give a green colour and even treated as a healthy alternative appealing taste when eaten raw, so then flaked and added to sauces, soups to fast food. By and large, however, ‘grazing’ along the shoreline is unlikely and broths. In the United Kingdom, all of the seaweeds eaten in Australia to please the taste-buds. The coast of Porphyra is known as ‘laverbread’ and are grown overseas and imported, Western Australia supports more than is collected from the shore at low tide. arriving here already processed. But 1000 different seaweed species, and it Plants are boiled to make a spinach- with our vast coastline, we also have would be a huge undertaking to assess like paste, which is then thinly spread a great untapped natural resource, each one for edibility. Instead, it is on toast. In Wales, it is even added worth looking at the practices in other to cheese. Porphyra provides excellent cultures. Some 30 seaweeds are used nutrition. It has high protein content Previous page regularly as food in other countries. and is full of vitamins, trace elements Insets (from left) Foxtails (Asparagopsis). Many species or closely related species and minerals. The vitamin C content of Photo – John Huisman used by those cultures can be found in nori is 1.5 times that of oranges. Common kelp. Western Australia. This article examines Nori grows during the winter Photo – Julia Phillips just a few. months on rocks high in intertidal Ogo (Gracilaria), jelly weed (Betaphycus), areas. It looks similar to sea lettuce, sea lettuce (Ulva) and sea grapes Nori (Caulerpa). but is typically a purple colour. It is Photos – John Huisman Nori (Porphyra species) is one of the generally a plant of colder waters and, most valuable products yielded by the in Western Australia, does not occur Above left Alvarez’s jelly weed oceans. In Japan, fishers have cultivated further north than the Perth region. Kappaphycus ( ) growing on rope in a nori since the seventeenth century, by Balinese seaweed farm. Photo – John Huisman placing bamboo or brushwood poles Sea lettuce in the ocean to increase the available Sea lettuce is the common name Top Sea lettuce (Ulva). Left Nori farm in Japan. surface area for plants to grow on. used for blade-like species of the green Photo – Tadao Yoshida Annual production of nori in Japan algal genus Ulva. Plants are thin and Above A fully laden kelp harvester in is valued at well over US$1 billion membranous, being only two cells thick. France. Alginates will be extracted from these plants, some of which will end up dollars, making it one of the world’s Sea lettuce can be used directly as a salad in expensive French cosmetics. most valuable aquaculture crops. As vegetable, or cooked and added to soups. Photos – John Huisman

22 LANDSCOPE LANDSCOPE 23 The wonderful world of seaweeds Left Foxtails (Asparagopsis). Did you know? Seaweeds form the basis of a multimillion dollar industry that produces jellies and Below left Ogo (Gracilaria). thickening agents. The red seaweeds Kappaphycus and Eucheuma are cultivated Photos – John Huisman in several tropical countries for carrageenan, a component of their cell walls that is extracted and used in a variety of foods, industrial processes, medicines and cosmetics, to thicken and stabilise liquids. Carrageenan is commonly added to toothpaste and shampoo, so you might well be using a seaweed product every day! Seaweeds are also used in medicine. The red seaweeds Digenea simplex and Chondria armata (plus others) produce compounds such as kainic acid and domoic acid. These are toxic in large amounts but in small quantities provide an effective Foxtails anti-worm treatment. In Asia, Digenea extracts taken orally have been used as a Foxtails or iodine weed (Asparagopsis folk remedy to treat roundworm infestation for centuries. Several other seaweeds taxiformis) is regarded as the supreme including foxtails produce high levels of iodine and have been used in the treatment limu of the Hawaiians, where it goes of goiter (swelling of the thyroid). Other seaweeds are currently being investigated under the name limu kohu. It is so for anti-cancer activity. popular that many Hawaiian reefs Seaweeds can be used in gynaecology. When dilation of a narrow or closed cervix have been denuded of this seaweed, is needed before any gynaecologic procedure, a small tube of dried kelp seaweed and it is advisable to collect only Laminaria is placed in the cervix. This slowly absorbs moisture from the surrounding the fluffy upper portion, leaving the tissues and swells, gently opening the cervix and allowing access to the uterus and basal parts to regenerate. Plants are Above left Jelly weed (Betaphycus). fallopian tubes. This type of dilation greatly reduces the risk of injury. the Caulerpa fronds. These compounds cleaned thoroughly, soaked overnight Above Digenea from tropical Australia Seaweeds are the only source of agar, a complex carbohydrate that is extracted in fresh water (an essential step to have demonstrable impacts on animals —used elsewhere to combat roundworm from some red seaweeds that solidifies at room temperature. Agar is used in many remove potentially toxic compounds) and on human cells, but the general for centuries. industrial processes and in the production of agar plates for microbiology. and then lightly salted. Pieces are then belief is that the levels that might be Right Hair weed (Lyngbya)—one to Seaweeds are also a wonderful addition to the garden. As well as being excellent rolled into small balls and added to ingested are not sufficient to cause problems. In other countries, sea grapes avoid! mulch, brown seaweeds are used commercially to produce fertiliser. These seaweed- raw fish or stews. The flavour is very Photos – John Huisman derived fertilisers contain growth promoters and also compounds that enhance the strong and peppery, so only a small are reported to develop a bitter taste at health of plants, increasing their resistance to disease and attack by pests. amount is used. Strangely, this seaweed particular times of the year, presumably finds favour with very few people not as a result of toxin accumulation, so of Hawaiian origin, and its usage is any plants with a bitter taste should be virtually restricted to the Hawaiian avoided. Islands. There have also been reports of Caulerpa causing an allergic reaction, Ogo with symptoms including dizziness, Ogo (Gracilaria species) can be eaten numbness at the tip of the tongue, of marine turtles in Queensland. This raw, but some people recommend it and breathing difficulties. Whether species grows to about 20 centimetres these symptoms are the result of toxins tall and looks very much like coarse, first be plunged into boiling water for John Huisman is a contract seaweed two to three minutes. It then becomes produced by the seaweed, or something dark purple or black hair. It is definitely specialist at the WA Herbarium an attractive green while retaining its ingested coincidentally, is not known. one to avoid! and a research fellow at Murdoch crispness. Ogo is a vital component of Incidences of food poisoning from Certainly, some caution is University. He is an international the Hawaiian dish poke (pronounced eating the red algae Gracilaria and appropriate. Only eat seaweeds taken expert on seaweeds, having studied Acanthophora have been reported in from unpolluted areas and which WA’s marine plants for more than 20 po-KAY), which is essentially cubed years and written several books on raw fish (generally sashimi-grade tuna), the tropical Pacific (such as in Guam, are themselves clean of associated marine plants from various parts of combined with soy, sesame oil, toasted Hawaii, Japan and the Philippines). epiphytes (attached plants). Never eat the world. One outbreak resulted in eight deaths, seaweeds growing in the proximity of sesame seeds, chopped ogo and sea salt. If you enjoyed this article then look The mix can be served immediately or but it is suspected the causative agent Lyngbya. For the most part, seaweeds out for the new full colour pocket- Another option is to toast sea lettuce. caviar. They are eaten raw and can have refrigerated for an hour or two. was not the seaweed, but associated that taste good will not be harmful—it sized Bush Book, Marine plants of Plants are cleaned then rubbed with a a pleasant crunchy texture, as the small microorganisms ingested with it. is perhaps redundant to say, but do the Perth region, which John has mixture of sesame oil and salt. Several grape-like vesicles ‘pop’ in the mouth. Is it safe? One of the compounds implicated in not eat anything that is particularly cowritten. It contains a wealth of sheets are then rolled together and left In south-east Asia, sea grapes are The vast majority of seaweeds these deaths is known as aplysiatoxin. distasteful. There is little danger of information on our local seagrasses and seaweeds. to stand for five minutes. The sheets are cultivated for human consumption. Sea do not produce compounds that are Aplysiatoxin was first discovered in being poisoned by seaweeds that taste It is available from most then unrolled and cooked separately in a grapes (Caulerpa racemosa) is the only harmful to people. Some species in the sea hare Stylocheilus, but actually pleasant. bookshops, Department hot pan until crisp, then cut into smaller species of seaweed mentioned here the genus Caulerpa, including sea originates in the blue-green alga Remember, despite the implications of Environment and pieces and served with rice. where some caution is advised, as it is grapes, have been reported to show Lyngbya majuscula that forms part of the of the name, all our seaweeds are native Conservation offices known to contain certain compounds some human toxicity. They produce sea hare’s diet. In the tropics, Lyngbya to WA coasts and their collection and online through Sea grapes NatureBase that could cause a reaction in people. substances, such as caulerpin, can be a common inhabitant of reef is managed by the Department of (www.naturebase.net) Some species of Caulerpa (C. If plants have a strong peppery flavour, caulerpicin and caulerpenyne, which flats and is known to cause contact Environment and Conservation. Before for a recommended racemosa and C. lentillifera) are eaten they are probably best avoided (see the appear to repel grazers and possibly dermatitis (‘swimmer’s itch’). There are gathering plants, ensure that appropriate retail price of $6.50. under the names sea grapes or green section ‘Is it safe?’). stop other organisms from settling on also cases of Lyngbya causing the death licenses are obtained.

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