What is Seaweed farming?

Seaweed farming is the practice of harvesting various species of seaweed, commonly known as aquaculture. Seaweed has vast impacts on its surrounding ecosystems such as:

• Reducing wave energy

• Protecting shorelines for coastline ecosystems 

• Elevating pH

• Supplying oxygen to the waters, thereby locally reducing the effects of de-oxygenation.6

• Sucking up carbon dioxide and using it to grow, which can help to combat local impacts of ocean acidification.1

• Gobbling up nitrogen and phosphorus which causes harmful algae blooms.

• Providing shelter for other marine organisms, allowing more diversity in its ecosystem.

Farmers can grow various types of seaweed including dulse, bull kelp, ribbon kelp, sugar kelp, and many more. These are used in sushi, salsas, sauces, salads, seasonings, and other food products.1 Farmed seaweed is also an ingredient in cosmetics, animal feed, biofuel, and fertilizer.6

In the Puget Sound region of the US and Canada

Seaweed farms can be strategically placed to help other types of aquaculture thrive. For example, in the Puget Sound region located on the west coast of the US and Canada, ocean acidification and pollution are proving difficult obstacles for many shellfish farms. Their harvests become smaller every year due to the lack of carbonate ions available for them to build their shells. Acidification causes a reaction with water, carbon dioxide, and carbonate ions and turns them into bicarbonate, therefore, depleting carbonate ions from the water. This process puts considerable stress on shellfish, especially larval shellfish who have yet to develop shells, and therefore has led to smaller harvests both in size and quantity for farmers. 

Shellfish farming is an essential industry for the Puget Sound region; it is tightly ingrained in the local economy and in many Indigenous Tribes, such as the Salish Coastal Tribes. These Tribes have relied heavily on shellfish for food, and have incorporated it into many traditions. While steps by the indigenous tribes are being taken to address the pollution issue in the region, there is an additional solution: seaweed farms. 

Because seaweed farms can locally reduce the impact of ocean acidification and locally purify water, there is a huge potential to establish seaweed farms close to shellfish farms to create a natural buffer from the effects of ocean acidification, thereby allowing both industries to succeed. Many industries around the world are already practicing these methods and they are showing promising results.

Global Trajectory

Much of the world’s seaweed is produced in sea-based farms off the coasts of China, Indonesia, the Philippines, South Korea, and Japan.3 In other regions like the US and Canada, seaweed farming is almost non-existent in comparison, but dozens have been created in recent years.1 Furthermore, seaweed farming is not limited to just these parts of the world, it is a top crop in East Africa, it is gaining traction in Europe, and indigenous people in South America, specifically Chile, have incorporated seaweed in their diets for many years.7, 8

 The Food and Agriculture Organization (FAO) of the U.N. reported 25 million tons of algae and seaweed worldwide were harvested each year.7 Moreover, the annual value of global seaweed production was estimated to be worth over $6 billion in 2012.3 A 2016 report from the World Bank estimated that if the market can increase its harvest by 14% each year, the annual global seaweed production could reach 500m dry tons by 2050. They report that hitting the 500m mark would boost the world’s food supply by 10% from the current level, create 50 million direct jobs in the process and, using microalgae as a biofuel it could replace about 1.5% of the fossil fuels used to run vehicles.3

 In Chile alone, seaweed provides alleviation of poverty, food, and food security to rural areas where the poverty rate stands at 47%.7 An increase in the industrial use of seaweed for food, animal feed, and biofuels could represent a transformational change in the global food security equation and in the way we view and use the oceans.3

Written by Kathryn Hofius

References

1. NOAA. (2020, September 28). Seaweed aquaculture. Retrieved April 4, 2021, from https://www.fisheries.noaa.gov/national/aquaculture/seaweed-aquaculture

2    Ferrandez, C. (2021, January 12). Innovating seaweed farming all over the world. Retrieved April 4, 2021, from https://atseanova.com

3    Fehrenbacher, K. (2017, June 29). Meet the new us entrepreneurs FARMING seaweed for food and fuel. Retrieved April 4, 2021, from https://www.theguardian.com/sustainable-business/2017/jun/29/seaweed-farms-us-california-food-fuel

4    Carlowicz, M., & Stevens, J. (2021, January 15). 2020 tied For warmest year on record (1304530911 959752712 P. Przyborski, Ed.). Retrieved April 4, 2021, from https://earthobservatory.nasa.gov/images/147794/2020-tied-for-warmest-year-on-record

5    EPA. (2019, August 21). Shellfish harvesting. Retrieved April 4, 2021, from https://www.epa.gov/salish-sea/shellfish-harvesting

6    Duarte, C. M., & Wu, J. (2017). Can Seaweed Farming Play a Role in Climate Change Mitigation and Adaptation? Frontiers in Marine Science, 4(100). doi:10.3389/fmars.2017.00100

7    Marrone, R. (2020, May 26). Seaweed farming aids food security in South America. Retrieved April 12, 2021, from https://borgenproject.org/seaweed-farming-in-south-america

8 Deliso, M. (2020, July 14). As seaweed becomes a top crop in East Africa, a new program will help farmers grow it sustainably. Retrieved April 12, 2021, from https://abcnews.go.com/International/seaweed-top-crop-east-africa-program-farmers-grow/story?id=71676150