Seaweed Cultivation, Coastal Community Business Opportunity

Indonesia is an archipelagic country with a very rich marine and fisheries sector. No wonder we are known as one of the largest marine resources in the world. One of the prima donna of the sea that has brought coffers to the country and Indonesian farmers is seaweed cultivation.

Seaweed is one of the main commodities of aquaculture which is a mainstay in increasing production, improving the regional economy and the welfare of coastal communities. The development of seaweed cultivation in a synergistic and simultaneous manner is part of the vision and mission of the development of the Working Cabinet to encourage the sea as a source of the nation's economy in the future.

Indonesia is currently the largest seaweed producer in the world for Eucheuma cottonii and Gracilaria grass species. “For cottonii, our production reaches 97.83 percent of world products, while for gracilaria it reaches 96.4%. This is based on FAO statistical data in 2014. In 2014, our seaweed production reached 10.23 million tons and in 2019, our production target reached 19.5 million tons. This target is optimistic that it can be achieved considering the potential land area for marine cultivation throughout Indonesia.

Although it is known as the “sea”, this is not as difficult as the work of fishermen who have to go to sea both in the afternoon and at night to look for seaweed.  

Also read: A Complete Guide to Arowana Fish Cultivation

How to cultivate seaweed

In principle, there are seven methods of seaweed cultivation known in the province of East Nusa Tenggara which is one of the national seaweed production centers.

The first is to use the seeds from the best tallus. Second, Discipline harvesting at the age of 40-45 days, then third, not using fertilizers/probiotics/growth-boosting materials. Next, fourth, seek to find new cultivation areas for rotation of planting. In addition, fifth, we must protect the beach environment from garbage (plastic, etc.). Next, sixth, don't dry the seaweed on the sand and keep it from other sticking materials and the last, seventh, immediately cover the seaweed that is being dried with plastic/tarpaulin if it rains. By applying this technique, seaweed cultivation will be successful and will continue to support increased production and quality. 

Seaweed cultivation can also be done either through a monoculture system in the sea and ponds or a polyculture system. For polyculture systems, gracilaria grass cultivation can reduce the risk of white spot attacks in shrimp farming. So that in addition to optimizing land productivity, it also prevents disease attacks in shrimp farming.

There are several procedures for cultivating seaweed which can be explained with the following description. 

1. The importance of choosing a cultivation location 

Before starting the cultivation process, there are several things that must be considered as follows. 

• Make sure to choose a location with calm water character
• The water depth can't be less than 70cm at low tide, and no more than 200cm at high tide
• The place and location is protected from strong sea breeze
• The location must be in a muddy or slightly sandy place
• Irrigation canals must be fertile

If we live near a coastline or sea location, then this will be very beneficial in the cultivation process. 

Also read: Harvest Fast! Here Are 9 Natural Catfish Foods To Get Big Fast

2. Seaweed planting test 

After knowing the location of cultivation, it is necessary to test the location by planting seaweed. This step is to prove whether the land used is appropriate or not to reduce standard losses during the planting process. Testing the planting location can be done using the net and rope method. 

The type of rope that can be used is a monofilament rope that is attached to two piles, with a distance of less than 10 to 12 meters.

For the planting test using the net method, use a 5m x 2.5m monofilament rope tied to a pile.

3. Choosing a seaweed cultivation method 

There are 3 methods of cultivating seaweed in the ocean, namely floating raft, off-bottom, and long line method. Methods in cultivating seaweed:

• The floating raft method is usually used in rocky waters, so the planting uses bamboo or wood.
• The Off-bottom method is used in sandy or muddy waters, so that it is easy to mount the piles.
• The Long Line method uses a 50-150m long rope that is stretched, anchored on both sides and a large buoy. Every 25m given buoys.

4. Seed selection and collection

The next step that can be done is to collect seeds obtained directly from the ocean. Methods of collecting seeds can be done by several types of methods such as spontaneous dispersal and stored in the sun.

Other types of seed collection that can be done are soaking seawater with a concentration of 1.030 g/cm?3; for 25 minutes. Choose good seaweed seeds with the following characteristics:

• Many branched and lush
• There are no spots
• Not peeled off
• Bright colour
• Age 25 - 35 days
• Should be collected from the coastal waters around the location and the amount according to need.

Also read: How Easy, These Are 6 Ways To Raise Guppies For Beginners

5. How to plant seaweed seeds 

When transporting the original seeds, the seaweed seeds must be submerged by water. Therefore, farmers use  Styrofoam  to remove seedlings from their habitat.

 

Arrange the grass seeds in layers and alternate between the base of the thallus and the tip of the thallus. Apply layers of cloth that have been moistened with seawater one layer after another. 

There are several ways to grow seaweed in detail as follows: 

1. Prepare a rope to hang the seeds, then tie it on the hanging rope
2. Extend the rope containing the seaweed ties and position it 30cm above the water.
3. The ideal distance of the rope span is about 20cm-30cm.

6. Taking good care of seaweed 

In order for the growth of seaweed to be smooth and the harvesting process far from problems, you must also take care of this as well as possible. The yield will be determined here, so that the treatment process must also be considered to produce superior seeds.

There are some inspirations in caring for seaweed:

• Clean the seaweed thallus from the pest plants that grow around it
• There are several disturbing pests such as sea cucumbers, sea urchins, larvae, baronang fish and other herbivorous fish. 
• Make sure the sunlight enters the water. Check seaweed for disease.

The treatment for seaweed is as follows:

• At the time of transportation, the seedlings remain submerged in sea water using a styrofoam box or plastic-coated cardboard. Then the seeds are arranged in layers and alternately between the base of the thallus and the tip of the thallus and between the layers is limited by a cloth that has been moistened with seawater. 
• Avoid seeds so they are not exposed to oil, rain or drought.
• Next, the seeds are tied with raffia rope on a hanging rope.
• Planting can be done directly by stretching the Ris rope which already contains plant ties. In the main Ris rope, the position of the plant is about 30 cm at the bottom of the water. 
• The wooden stake is about 5 cm in diameter, 1 m long and pointed at the lower end. The distance between the stakes for stretching the Ris rope is about 2.5 m. 
• Each lined peg is connected by an 8 mm diameter Ris Polyethylene (PE) rope. The ideal distance between the ropes is about 20-25 cm.

Seaweed Care and Maintenance:

• Clean the thallus from weeds and adhering mud, so that it does not block the plant from sunlight.
• Clean the leash from trash or weeds.
• Check the integrity of the leash, repair it if it breaks or tighten it if the rope is a bit loose or replace it with a new one.Check plants for disease.
• Other grass pests to watch out for include sea urchin larvae, sea cucumbers, herbivorous fish such as baronang.

Also read: How to Raise Catfish with the Biofloc System

7. Seaweed harvesting process 

After going through a fairly long cultivation process, the final stage that must be done is harvesting the results. Harvest time is also adjusted according to the method and process of cultivation to be carried out. If the goal is a nursery, you can also harvest seaweed between 25 to 35 days. Meanwhile, for business needs and other processed products, it takes about 45 days. 

The harvesting process is carried out by lifting the entire plant and the hanging rope. If the grass has been harvested, you can dry it in the sun slowly. The drying process can be done for 3 to 4 days depending on weather conditions. After the harvest process is done perfectly, you can sell it even if you process seaweed into delicious food. 

Seaweed Harvesting and Drying:

1. Harvest time depends on the destination. To get the seeds, harvesting is done at the age of 25 - 35 days, and for high-quality production with a lot of keraginan content, harvesting is done at the age of 45 days. 
2. Harvesting is done by lifting the entire plant along with the hanging rope. The release of plants from the rope is done on land by cutting the rope.
3. After harvesting is done, immediately dried directly by drying. 
4. Seaweed is dried by hanging or placed on a parapet so that it is not mixed with sand, soil and other objects. 
5. While drying, cleaning is done from dirt by taking foreign objects such as stones, garbage and others. 
6. If the weather is sunny, enough to dry for 3-4 days which is marked by a whitish purple color coated with salt crystals.

Seaweed cultivation is very profitable because the cultivation process does not require a high level of skill and large capital, so that all can be done by residents who live in coastal areas.