Understanding the biology of seaweeds paved way in the development of technology for seaweed farming. Seaweed farming is cultivating and harvesting commercially viable seaweed species such as Kappaphycus alvarezii, Kappaphycus striatum and Eucheuma denticulatum. Farmers put up their farm in suitable area basing their judgement to the biological requirements for seaweed growth. Then, they collect seaweed in the area as their starting planting material. They tend to their farms for 2 months before harvesting the seaweeds and hang them under the sun to dry.
History of seaweed farming started in Tokyo Bay, Japan as early as 1670. Since then, methodology had evolved from farming seaweeds in shallow water through bottom-staking method to farming seaweed farms in deep waters using monoline rafting or spider web method. Whatever is the method, the goal is to ensure increase in seaweed production.
Farming seaweed has both positive and negative impact. Let’s start with the negative impact. Environmentally, farmers cut down sapling mangroves to use as stakes for their farm since it is the most nearest source they have. Farmers also remove eelgrass within the perimeter of their farming area. Both of these actions could lead to depletion of mangrove biodiversity and seagrass cover in the area further resulting to poor water quality. Such actions should be discouraged.
On the physical aspect of marine environment, unregulated construction of seaweed farms have resulted to obstruction of navigational way and altering the normal flow of water. This had been an inconvenience to recreational boaters and others sharing the coastal zone.
Now, let’s look at some of the positive impact. Seaweed farms provide shelter and safety for Siganid fry and other fry of fish species as well as crustaceans. Seaweed farms also aid the preservation of coral reefs by increasing diversity where the algae and seaweed have been introduced. A seaweed farm also provides oxygen, the by-product of photosynthesis, used for respiration by most marine organisms.
In the Philippines, a change from illegal fishing activities such as dynamite and cyanide fishing practices to seaweed farming is also an observed impact. Seaweed farming has been viewed as a strategy for resource management encouraging coastal communities to change from resource destroyer to sustainable resource managers.
Another positive impact of seaweed farming is that it provides income and potential job generations which are at its highest today in history. Another big plus is that it provides employment opportunities for women. Seaweed farming is considered as the most productive form of livelihood in coastal communities, benefiting more than half a million of the population in the Philippines.
Aside from the positive impact to the environment as well as the household economy, why is seaweed farming very important? Cultivating seaweeds guarantee unceasing supply of carrageenan.
Carrageenan works as thickener, stabilizer and emulsifier in foods and other products. It helps prevent mixed ingredients from separating. All of us, in one way or the other, have tasted and used products with carrageenan. Ice cream, yogurt, milk shakes, sweetened condensed milks, cottage cheese, jelly, chocolate, salad dressing all has carrageenan. Some companies also used carrageenan as meat extender. I’m pretty sure we all love beer and yes, they do use carrageenan as a clarifier that removes haze-causing proteins. For non-food items, toothpaste, lubricants, gels, plastic wares, shampoos, cosmetic cream, shoe polish and even some ropes has carrageenan.
In drying seaweed per species, the farmer can demand for a better price since each species has different gel strength. They are referred to as classes of carrageenan namely:
- Kappa class mostly produced from Kappaphycus alvarezii and K. striatum. Produces a solid, firm gel when mixed with water, and is known for reacting well with dairy proteins.
- Iota class from Eucheuma denticulatum. Produces a soft gel when mixed with water, and tends to gel more easily when combined with calcium.
- Lambda class from species in the Gigartina genus. This class does not gel in water, although it will in the right concentration in milk; it is more often used as a thickener than to cause a product to gel.
Production of carragenan makes seaweed farming very important to us and to our economy. However, due to effects of the changing climate, it is getting harder to achieved volume in production from farming seaweeds. Just recently, typhoon BOHPA unleashed strong waves that destroyed 5.8 million pesos worth of seaweed farms in Hinatuan, Surigao del Sur, Philippines.