Seaweed is one of the potential fishery commodities and began to be developed for many cultivated because of the many benefits of seaweed. The benefits of seaweed, among which can be used as pharmaceutical products, cosmetics, food and others. Gracilaria sp. and Eucheuma sp. is a type of seaweed that is widely cultivated in Indonesia. Gracilaria sp. including in the class of red algae (Rhodophyta) and is a type of seaweed producing agar (agarofit), while Eucheuma sp. is a type of kelp karaginan (karaginofit).

Location Selection

Environmental factors that must be considered in the selection of seaweed cultivation are:

Being in the tidal area so as to facilitate the change of water by gravity.
The bottom of the waters is muddy sand.
Free from pollution waste.
The waters are quite clear with a brightness level of 40-60 cm.
Salinity between 15-30 ppt, but optimal at 20-28 ppt.
Water temperature between 20-28 ° C
pH between 6-9.
In seaweed cultivation efforts, planting trials should be tested to determine the growth of seaweed at selected locations and see what location has the feasibility for seaweed cultivation. In addition it should also note the availability of used, then made the selection of methods of cultivation.

Method of Cultivation

There are several methods that have been developed in seaweed cultivation, among them:

The basic method (bottom method)
In this method the seeds of seaweed tied then spread to the bottom of the water. Can also be done by tying the seeds of seaweed on the rocks. The basic offshore method is suitable for cultivation sites on a flat, un-sandy and un-sandy coral basis.

Floating raft method
The floating raft method is done by planting using a floating raft measuring between 2.5 x 2.5 m2 to 7 x 7 m2 which is generally made of bamboo diameter 9-10 cm. In order for the raft to not be carried by the current, it needs to be retained by anchoring or tied to a wooden stake that faces each other on both corners of the raft and plugged into the bottom of the water. This method is suitable for waters that have a depth of 60 cm.

Long line method.
The longline method is done by binding the seaweed seedlings to the rising rope with a length of 25 m and using 2 stakes / pegs. On the rising rope tied a child's rope to each other between 25 cm apart. Used buoys that can be made from bottles, buoys tied along the rope every 2.5 m.

Provision and Planting of Seedlings

After the selection of seaweed cultivation method, the next needs to be done provision of seeds. The characteristics of good seeds, ie elastic thallus, have many branches, the base is larger than the end of the branch, the tip of the thalus is straight, the color is bright and smelling fresh, clean of pests, pests and dung plants, if the thallus is cut feels brittle, spots and uniform seed shape. Seeds planted in the form of young thallus originating from the tip of the thallus. Planting should be done during the shade in the morning or evening. Seedlings avoid the heat of the sun and cultivated always wet.

Maintenance

Seedlings that have been ditanan need to be treated and supervised to avoid any diseases or pests contained in the seeds. If the disease or pest, the seeds need to be cleaned of dirt or pests or even replaced. If there is an accumulated growth of seaweed, it needs to be smoothed to avoid decay and formation of H2S gas. Checks can be done once a week, but in unfavorable weather conditions such as tight currents checking should be done more often about 2-3 days.

Harvesting

Harvesting is done after the seaweed reaches a certain weight, usually after 45-60 days. Harvesting is done by taking seaweed from the waters then seaweed washed before being transported to land. Harvesting should be done in the morning so that during the day seaweed can be dried in the sun. It also avoided harvesting in the event of rain.