Depending on the type of seaweed, the reproduction process differs and therefore the complexity of obtaining seed material does as well. The seeding method is the process of bringing the seed material on to the line used for grow out. The method for attaching these seeded lines to the farm site is called deploying.
Seed material for Gracilaria can be obtained by vegetative propagation either from wild or harvested crop, year-round.
Seed material is sourced either from the wild, where branches of or entire reproductive plants are collected or from plants obtained in previous cultivation. In China, when the cultivation season is over in the South, some of the harvested Gracilaria will be transported by truck up to Northern China and used as initial seed material when the cultivation season starts there in May.
In pond culture, these seedlings are simply scattered across the grow out pond. When farming Gracilaria at sea on ropes, the seeding process is highly labour intensive. In Indonesia, fragments will be tied to the culture line, which uses the same materials and technique as seeding the lines for Eucheumatoids farming. In China, the fragments will be inserted into the twisted rope, just like in the seeding process for Saccharina.
In a second step the line with tied seedlings is deployed or in other words attached to the farm setup at sea. Alternatively the tying can also take place on the farm site by boat or walking if the water depths at low tide allows for it – however it requires much more time at sea.
The seedling from spore of Gracilaria attached at the nylon line for long line method in Indonesia. (Photo courtesy of Boedi Julianto)
Gracilaria seedlings after one week at the farm site. (Photo courtesy of Boedi Julianto)
Another form of seed production can take place in a hatchery setting, by having spores from reproductive Gracilaria plants settle on the surface of ropes. This process can be seen in the pictures below.
The Brackish Water Research Center Takalar, Indonesia and Unido are collecting spores from parent stock of Gracilaria changii to provide farmers with high quality seed material. (Photo courtesy of Boedi Julianto)
Spores will attach to the nylon line and will then be grown in tanks before transferring them to the sea. (Photo courtesy of Boedi Julianto)
After 7 days, the Gracilaria grow out the propagules attached at the nylon line. (Photo courtesy of Boedi Julianto)