Grow Out
The time it takes for seaweed to grow from deployment to harvest varies significantly between tropical and temperate species. Seaweeds are low trophic species and generally do not need to be fed during the grow out process. Yet once the lines are in the water, some species require more attention than others. Risks during the grow out phase include epiphytes, diseases, pests, aquatic animal grazing and even strong weather events. Technology usage for production planning, communication or monitoring indicates how widespread digital solutions are.
Explore Grow Out by Species
Saccharina
Saccharina is only farmed in the winter months. Cultivation lines are deployed starting from early November to December and grow out period lasts until March to April the following year. The exact timing depends on the region.
Well distributed Saccharina at a farm site with relatively clear water and high water motion North of Busan in South Korea.
Saccharina growing well at with turbid water at a farm site in China. (Photo courtesy of Innovation Norway)
In the North of Japan, the grow-out time at sea starts around the end of October and usually takes around 10 months. The harvest takes place between mid June and mid August. In South Korea and most locations in China, the grow-out period is usually not longer than 5 months, from October til February or March.
The deployment of the cultivation lines is highly weather dependent and time-critical. In Northern China, there are typically can be millions of lines to be deployed on large farms, which can easily take up to 2 months.
Between January and April, when the water temperature and light intensity rises, the depth of the culture lines needs to be adjusted regularly using additional floats. Such work is typically done by two people per boat and is a fairly repetitive and heavy task.
Each Saccharina blade can easily grow up to 8 meters. Farm visit in Wando, South Korea.
Saccharina blades start rotting when the water temperature rises in spring. This picture was taken mid March in Xiapu Fujian province, China. (Photo courtesy of Innovation Norway China) I
Furthermore, throughout the grow-out time, regular ‘thinning out’ will need to be done, to ensure good growth of high quality blades. This means, small blades will be cut out manually. In South Korea this happens on a much more regular basis. Japanese farmers usually wait for two months until the blades have grown up to one metre until they conduct the first selection. In March the second selection or thinning out will take place. Farmers also need to clean the lines from any other algae, fouling shellfish or other foreign matter.
During the grow out period, the farmer needs to take good care that the blades keep clean and free from any biofouling.
The blades will grow heavy on the culture line to the point, where a crane is essential for working the lines.
Technology use
Most Saccharina farmers base their farming decisions on intuition and experience. The large corporate farms use conventional spreadsheets to keep track of their production.
Communication regarding farm operations is mainly done through verbal instructions and instant messaging services.
Explore another seaweed species:
Eucheumatoids | Saccharina | Undaria | Pyropia | Gracilaria
Or continue to the next Farm Insights
