Seaweed Cultivation & Algal Industry

Of the global seaweed harvest, 85% – 95% goes to the food industry and is worth approx €4.1 billion per annum (p.a.). The most valuable crop produced by seaweed aquaculture is Nori – Porphyra – a red seaweed or alga. The value of this crop is around US$ 2 billion p.a. (approx. 130 t dry weight)

The seaweed that produces the largest amount by aquaculture is Laminaria japonica. China produces around 3.8 million tonnes p.a. of Laminaria japonica.

The majority of the seaweed industry is by aquaculture in Japan, China and North & South Korea.

Country/Area  Seaweed (fresh weight
million t ) 
World production (%)
China 4.093 59
Korea 0.771 11
Japan 0.737 10
Philippines 0.404 6
Far East countries (total) 6.263 90
Norway 0.185 2.6
Chile 0.182 2.6
USA 0.116 1.6
France 0.079 1.1
European countries 0.302 4.3
Total 6.941 100

World Journal of Agricultural Research 2014

One of the biggest benefits of this expansion is a healthy food habit of consuming algae.

We can say that the algae are like the sea vegetables, i.e., plants that grow in water, both fresh and saltwater.

But we must be clear that not all the algae that are at sea can be used in food. In fact, only some 50 species are edible, of the total of 25,000 hitherto known.

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One reason for the differentiation among species is that over 2,000 million years of life have evolved and diversified to adapt to different ecological circumstances of their
habitat, or the sea.

Author’s Note: Anyone interested in writing a detailed article on ‘Seaweed Farming Techniques’ can mail me at plantletorg@gmail.com

Status of Production & Utilization of Seaweed in China

Seaweed production in China is mainly from artificial cultivation along the coast, the annual output has reached 250,000 metric tons dried product (1.25 million tons fresh), with a value of about 300 million yuan

The economic species that are being cultured are Laminaria, Porphyra, Gracilaria, Undaria, Gelidium, Eucheuma, etc.

The major processed products are alginate, iodine, mannitol, carrageenan, agar and other seaweed food.

Seaweeds Cultivation in Japan

Nori (Porphyra) (Porphyra tenera, Porphyra yezoensis, Porphyra haitanensis, Porphyra purpurea, Porphyra cordata) cultivation started about 300 yrs ago and harvested quantities are increasing
every year.

The cultivation of Undaria has recently grown to an industry and the one for Laminaria has just begun.

Monostroma has been cultivated for 30 yrs, and in the past 10 yrs, the amount of its harvest has kept a constant level, satisfying the consumers’ demands.

The amounts of Laminaria, Undaria, Gelidium, etc. harvested from their natural beds have not increased much from year to year.

Seaweed Production

99.4% seaweed production is from seven countries in Asia (FAO 2012). They are:  China, Japan, S. Korea, N. Korea, Indonesia, Philippines and Malaysia.

Seaweed production countries. (FAO, 2017). From Food and Agriculture Organization of the United Nations, Fisheries and aquaculture software. FishStatJ-software for fishery statistical time series. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 21 July 2016. [Cited 10 January 2017], http://www.fao.org/fishery/ statistics/software/fishstatj/en#downl

BARC (Bangladesh Agricultural Research Council) has taken some initiatives to explore avenues of seaweed culture in Bangladesh.

Bangladesh’s coastline is about 700 km, 25,000 km2 of coastal area with a huge population, supporting a variety of land use practices. It is beset with sandy and muddy beaches, estuaries and mangrove swamps. There are suitable substrate and habitats for various seaweed cultivation.

So far, 133 seaweed spp. have been reported from Bay of Bengal, of which ten are commercially important.

In our country, arable lands are decreasing at 1% per year. So seaweeds (marine macro-algae) of vast littoral coastal zones must be explored to meet different demands. It is estimated that seaweeds highest production may reach 9000 kg/m2/year which is 3 times more than agricultural crops.

But unluckily, peoples of Bangladesh are not aware of seaweed as food.

Some researches on Seaweeds in Bangladesh

  • Phycology, Limnology, Marine and Environmental Science and Biodiversity Laboratory, Department of Botany, University of Dhaka
  • Bangladesh Agricultural Research Council (BARC)
  • Bangladesh Agricultural Research Institute (BARI)
  • Department of Agricultural Extension (DAE), Government of the People’s Republic of Bangladesh.
  • University of Chittagong
  • Bangladesh Agricultural University, Mymensingh
  • Ministry of Fisheries and Livestock , Government of the People’s Republic of Bangladesh.
  • Biomass production of Hypnea sp. cultured at Saint Martin, Bakkhali and Inani were 11.05±0.10 kg/m2, 9.86±0.18 kg/m2 and 7.82±0.04 kg/m2 respectively.

Seaweed culture in the coastal area of Bangladesh

About 40 seaweed species are commonly available in the coast of Bangladesh, of which 10 are commercially important.

  • In the Cox’s Bazar coast seaweeds Hypnea, Padina & Sargassum spp. are cultured;
  • Seaweed culture is a very much seasonal activity (Nov. to March) in our coast.

In Bangladesh, seaweeds have been traditionally utilized as human food by the tribal people. In recent years, few Chinese restaurants are often used seaweeds as fresh salads, cooked vegetables, fish curry and meat dishes.

Seaweed is also an ingredient for bio-chemicals, pharmaceuticals and cosmetics industries in Bangladesh but there is no regular seaweed industry in Bangladesh

Approximately 15 metric tons of seaweeds were produced in 1989. The total production was consumed in the country.

Bangladesh is not importing seaweeds directly, but in product form. e.g., agar. In 1987 the country imported two tons of agar from Japan and South Korea which could have been produced locally.

Commercially important seaweeds in Bangladesh

All of the ten species available in the country have economic value. The species are as follows:

  • Caulerpa sertularioide
  • C. racemosa
  • Entermorpha sp.
  • Hydroclathrus clathratus
  • Sargassum sp.
  • Gelidiella tenuissima
  • Halymenia discoidea
  • Hypnea valentiae
  • H. pannosa
  • Gelidium pusillum

Economics of Production

At present seaweeds are only harvested by gathering from natural stock. This production has a very little value from the economic point of utilization.

Processing and Utilization

Consumed locally both as fresh and as dried human food as well as animal feed. Only the people in the localities where seaweeds are gathered utilize them.

Research and Development Activities and Capabilities

The government is now planning to expand seaweed production through culture, initially around the natural beds and subsequently to expand and extend them to neighboring areas possessing similar ecological conditions.

Seaweed Cultivation in Bangladesh: Problems and Potentials

Seaweed farming is highly developed in many south-east Asian countries. But in Bangladesh, it is in an initial stage.

People in Bangladesh are still not aware of Seaweed cultivation.

Introduction of seaweed culture at areas suitable for their cultivation through familiarizing the poor farmers with cost-effective technology could open up a new avenue for expanding seaweed industry in the country.

The methods of cultivation of seaweeds using indigenous materials like bamboo and rope.

The main culture methods involve either vegetative propagation using fragments from mother plants or by different kinds of spores such as zoospores, monospores, tetraspores and carpospores etc.

Fragments of adult plants, juvenile plants, spores are seeded onto ropes or other substrata and the plants grown to maturity in the sea.

Seaweeds should be aimed for, as part of integrated coastal and national development programme.

Seaweed polyculture in association with mollusk, shrimp, mud crab and fishes seems to have good
prospects to increase harvest and profits.

Seaweeds with shrimp farming in coastal areas can help to treat the effluent water.

Markets and marketing organizations need to be established nearby cultivation areas to utilize the
resources efficiently with greater profits.

Bangladesh should therefore promote the cultivation and consumption of seaweed among
their people.


Despite the great potential of seaweed culture, no attempts on commercial production of seaweeds have been made in Bangladesh so far. Efforts are needed to increase production through improving harvesting techniques, creation of artificial habitats and seeding of suitable coastal areas.

The technology for the cultivation of different commercially important seed stocks and their improvements should be developed through research. In addition, extensive surveys need to be conducted to identify suitable sites for large-scale seaweed culture.

Experiences from China, Japan, Korea, Vietnam, Thailand and Philippines and Indonesia should be gathered.

Future prospects

Innovation, cultivation and niche markets – the combination of these three may lead to greater success for the uses of seaweeds and seaweed products in Bangladesh.

D. Myslabodski (Great Sea Vegetables, United States of America. pers. comm.) said:

Weeds are something we do not want, seaweed implies something negative about the product. When trying to convince others to eat it, “sea plants” or “sea vegetables” may be more appropriate words to describe it.

References & Other Links

Revised by 

  • Abulais Shomrat on 11th June, 2021.
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About Abulais Shomrat

Currently in 4th year (Hons) in the Department of Botany, University of Dhaka. Planned to have multiple careers one by one but promised to be with 'Plantlet' as long as it's primary stage remains unfinished. Email: abulaisshomrat@gmail.com. Minimum monthly resolution - Publish (1), Revise (3), Share (5)

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