Phil Cruver | Harnessing the untapped potential of the Caribbean seaweed industry | In focus


In recent years, seaweed has been considered a nuisance in the Caribbean as it clouded pristine beaches and discouraged tourism. The “weeds” in its name do not add to the public eye, so “seaweed” is used for the balance of this narrative to enhance the image.

Upon closer inspection, it becomes clear that marine plants are hidden environmentalists that are underestimated and not fully understood. Marine plants provide many ecosystem services and are a no-input food crop that does not require fresh water, fodder, fertilizer, or land that can be grown over vast areas of the sea. In addition, marine plants can double their biomass within two weeks and thus store enormous amounts of CO2 as a nature-based solution for the decarbonization of our planet.


According to the Food and Agriculture Organization (FAO) of the United Nations: “After half a century, game production remained at 1.1 million tons, while crop production rose to 35.8 million tons, which was 97 percent of the world’s seaweed production in 2019. The global production tonnage for seaweed cultivation increased 1,000-fold between 1950 and 2019 from 34.7 thousand tons to 34.7 million tons. “

Without China, Indonesia leads the world in marine plants, followed by the Philippines, which produces over 80 percent of the world’s carrageenan, which is used as a thickening, emulsifying, or suspending agent in the food, chemical, and pharmaceutical industries. Other countries are South Korea, North Korea, Japan, Malaysia and India. Zanzibar is also a major producer, employing around 25,000 farmers, around 80 percent of whom are women. In all of these countries, seaweeds are grown using traditional methods including the solid sediment method, the floating raft method, and the basket method. Notably, the multi-billion dollar carrageenan seaweed industry has remained artisanal despite its explosive growth.


Around 21 species of local seaweed are consumed as traditional beverages from the first half of the 19th century in 15 Caribbean countries. In the past 20 years, small beverage processing plants have been built in Jamaica, Barbados, Grenada, Antigua and Barbuda, Trinidad and Tobago, St. Vincent and the Grenadines, St. Lucia and Dominica.

Cultivation of Caribbean sea plants as biomass for the carrageenan extraction industry began in the 1970s, with St. Martin sea plant seeds being introduced to experimental farms in Guadeloupe and Martinique. The economic return has been too small to compete with Asian sources to make carrageenan, which sells for less than $ 1 a pound.

There is a potentially large market for regenerative and healthy marine plants harvested from pristine waters of the Caribbean Ocean and branded as “superfood” for the global food and dietary supplement industry valued at $ 168 billion. Marine plants contain 92 of the 102 essential minerals needed to strengthen the human immune system to fight COVID-19 and other inflammatory diseases. A superfood brand would also appeal to the emerging market of environmentally conscious and humane consumers looking for alternatives to unsustainable proteins made in polluting animal factories.

Therefore, the original target market for the Caribbean should be high quality exports of sustainable seaweed products for human consumption, where they have a brand advantage with proximity to the North American and European markets. In addition, the continued rapid expansion of the seaweed industry is being driven by a growing global demand for edible seaweed certified as pollutant-free. This competitive advantage, combined with the region’s questionable coastal water quality, poses a major problem for established complex Asian seaweed distribution systems. Transparent and traceable supply chains for seaweed will soon be mandatory to reassure informed customers that they are not consuming products grown in polluted waters contaminated with pathogens, heavy metals and microplastics.

The Caribbean has the potential to implement a cultivation and distribution system that allows the sea plant to be traced back to where it was grown and the day it was harvested in order to transparently meet health and sustainability certification standards. Consumers are increasingly willing to pay more for products that are sustainable, environmentally friendly, climate neutral and promote social justice. The demand in western markets for contamination-free and highly traceable seaweed products is expected to increase significantly, with growing interest in sustainable alternatives that can meet future food and health needs.

Another possibility, which is largely underdeveloped and which promises a transformation for the seaweed industry, is genetics for the development of seaweed with desirable properties such as a higher biomass yield and an increased tolerance to climatic changes. Unlike most land crops today, which have gone through thousands of years of selection, breeding, and domestication to produce superior varieties, there has been minimal research into advanced sea plant breeding. With modern biotechnology, the Caribbean could see rapid results for proprietary genetic enhancement of marine plants.


A late-breaking market in the commercial seaweed industry, the Caribbean is poised to use new technologies and innovations to improve the efficiency and productivity of agricultural systems that are more environmentally friendly and fit for the emerging blue economy.

Retractable seaweed structures with cage culture would achieve higher crop yields and offer protection from predators such as rabbit fish, turtles and long-pronged sea urchins as well as storm damage from typhoons in tropical regions. Additionally, the technology would provide traceability data on when and where the sea plants were harvested to meet stringent health and sustainability standards.

There is also a great opportunity to develop marine plant strains with advanced selective breeding techniques that are more sunlight, thermally tolerant and resistant to epiphyte disease. This research would include identifying solutions for optimal population densities and photon fluence values. Abiotic factors such as light, temperature, salinity and nutrient concentration in seawater have a major influence on the composition of marine plants. Recent research shows the correlation between the variation in seaweed compound caused by UV radiation and the salinity, which can be optimized by selecting the water depth in order to achieve a higher pigment yield.

The huge sea area in the Caribbean is currently not a limiting factor for the expansion of offshore sea plant mariculture, but climate change with the resulting changes in water temperature and water chemistry could lead to a future reduction in suitable nearshore cultivation areas. As a result, large-scale sea crop farms may need to be relocated further out to sea, requiring innovation to withstand the challenges of the harsh open ocean environment.

A new multidisciplinary movement is emerging in the global marine plant mariculture industry with an emphasis on biological and engineering sciences that the Caribbean region could use to create a new sustainable industry to diversify its tourism economy for post-pandemic recovery.

Phil Cruver is President of KZO Sea Farms, based in San Pedro, California. Send feedback to [email protected]


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