Caulerpa culture in South Sulawesi – an alternative for brackishwater pond culture

By Nana S.S.U. Putra, Imran Lapong, Michael A. Rimmer and Sugeng Raharjo

This is not only a profitable diversification from shrimp farming but restores shrimp ponds.

Lawi-lawi (C. lentillifera) from brackishwater ponds in Laikang,

 South Sulawesi. This variety is known locally as ‘bulaeng’

Since the 1990’s, shrimp production in Asian countries, including Indonesia, has fluctuated substantially, mainly due to emerging shrimp diseases such as white spot syndrome (WSSV), Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV), Taura Syndrome Virus (TSV) and Infectious Myonecrosis Virus (IMNV). Overall, these disease outbreaks have caused widespread economic losses amongst shrimp farmers in the region.

In Indonesia, it is estimated that more than 95% of coastal pond (‘tambak’) farmers are small-scale and disease-related crop failures greatly impact the incomes of these vulnerable farmers. Because of the ongoing production constraints associated with diseaserelated production losses in shrimp aquaculture, there is ncreasing interest in alternative production options for coastal pond farming. The requirements for alternative commodities are that they are economically profitableand easy for small-scale farmers to culture.

Since 2010, the Brackishwater Aquaculture Development Centre (BADC) Takalar has cooperated with several Australian and Indonesian institutes to implement an Australian Centre for International Agricultural Research (ACIAR) project titled ‘Diversification of Smallholder Coastal Aquaculture in Indonesia’. This project is trialling and evaluating various commodities that can be cultured in disused

shrimp ponds.

Our initial trials included an evaluation of swimming crab Portunus pelagicus, which were polycultured with milkfish Chanoschanos and seaweed Caulerpa spp. to provide additional production in the event that the crabs did not survive. The trials were undertaken in brackishwater ponds,formerly used for shrimp culture, in Laikang Bay, Takalar district, South Sulawesi (5° 35’ 18” S, 119° 28’ 2” E). Our initial trials indicated that Caulerpa could produce a good income for pond farmers, so we have continued to investigate this commodity as an option for brackishwater pond production in South Sulawesi.

Ratte Daeng Bella, 

a local farmer, shows off 

the source of his new business.

Caulerpa as a promising alternative commodity

Seaweed production for carrageenan extraction (Kappaphycus alvarezii and Eucheuma denticulatum) is widespread in Indonesia amongst coastal communities, and Indonesia is currently the world’s largest producer of carrageenanproducing seaweeds. However, these seaweeds are usually cultured on lines in the sea (mariculture).

Another group of seaweeds that have not received much attention in Indonesia is the ‘sea grapes’ belonging to the genus Caulerpa. Caulerpa species are widespread globally in warm (25–30°C) coastal waters throughout Southeast Asia and the Pacific Islands, as well as in Africa. Caulerpa usually grows in shallow and open lagoons, on reefs and on a variety of substrates including sand and mud. Throughout their range, edible Caulerpa species are commonly consumed throughout their range, mainly from ‘gleaning’ or collecting from the wild.

In Indonesia Caulerpa is known as ‘lawi-lawi in Sulawesi and ‘latoh’ in Java. Although Caulerpa is used directly as a fresh vegetable in some parts of Indonesia, its culture has not been commercialised as is reportedly the case in the Philippines and Vietnam. However, Caulerpa is traditionally consumed in South Sulawesi as a fresh and cooked vegetable, and there is a strong local market in South Sulawesi.

Two species of Caulerpa are cultivated in ponds in South Sulawesi: C. lentillifera (known locally as ‘bulaeng’) and C. racemosa (known locally as ‘bu’ne’).

Pond site selection

The following recommended conditions for Caulerpa ponds are based on observation of successful Caulerpa production in ponds at Laikang, South Sulawesi. Ponds used for Caulerpa production should be close to the sea to maintain high salinity, have a mud substrate and be away from pollution sources and freshwater influence. The preferred salinity range is 25–30 ppt and Caulerpa will not grow at salinities below about 20 ppt. Like most macroalgae, Caulerpa is very good at bioconcentrating metals and contaminants, hence the need for culture ponds to be located away from pollution sources. Pond depth should be in the range 50–120 cm, to allow light penetration but also to prevent dramatic fluctuations in water temperature.

Caulerpa culture

Our first trials with Caulerpa culture in 2011, involved 4 ponds each around 0.5 ha. These trials demonstrated that Caulerpa biomass could increase by a factor of 10-13 times over a 3-month culture period, and the 4 ponds produced a total of 1.6 tonnes (wet weight) with a value of IDR 6 million (USD 625). This revenue (around IDR 3 million per ha for a 3-month crop cycle) compares favourably with our reference revenue for ‘traditional’ shrimp culture, which is IDR 1–5 million per ha per crop cycle of around 100 days.

Based on these promising early results, the project supported the expansion of Caulerpa culture in Laikang. This expansion was supported by development of a local farmer group facilitated by Dr Mardiana E. Fachri of the Faculty of Marine Science and Fisheries, Hasanuddin University, Makassar. Technical support to the group was provided by BADC Takalar through the ACIAR project. The second phase trials included 7 farmers, and the results are summarised in Table 1.

Table 1.   Monthly production of Caulerpa in ponds at Laikangin January- June 2012. All ponds were initially stocked with 160 kg of Caulerpa.

Farmer	Stocking Time	Monthly production (kg)						Total (Kg)
		Jan	Feb	Mar	Apr	May	Jun
1	Jan-12	-	560	640	2,240	2,280	3,400	9,120
2	Mar-12	-	-	-	600	800	1,200	2,600
3	Mar-12	-	-	-	-	560	1,160	1,720
4	Mar-12	-	-	-	600	1040	1,200	2,840
5	Mar-12	-	-	-	400	440	1,280	2,120
6	Mar-12	-	-	-	400	520	600	1,520
7	Apr-12	-	-	-	-	160	160	320
Total (kg)		-	560	640	4,240	5,800	9,000	20,240

Bags of lawi-lawi ready to be transported to 

local markets around Makassar, South Sulawesi

 Low investment

This is particularly important to poor coastal farmers who have little capital and usually limited access to finance. Planting a crop of Caulerpa requires only IDR 600,000 (USD 65). No additional inputs are

required during the crop cycle.

Simple culture techniques

Provided the pond site is suitable for Caulerpa culture, there is little management required to produce a crop. The main requirement is to have regular water exchange to maintain good water quality and renew nutrients for the plant growth.

Regular income

As Table 1 shows, Caulerpa provides a regular monthly source of income to farmers, rather than a single high income at harvest time which is typically the case with shrimp farming. This supports better spending patterns by the farmer household. Caulerpa culture also generates income amongst other members of the local community, such as people involved in harvesting the seaweed and transporting it to market. Consequently, there are indirect benefits throughout the community.

High profitability

On a per hectare basis, the production from the trial outlined in Table 1 represents revenue ranging from IDR 2.15 million to IDR 16.5 million per ha over the six-month period. This compares favourably with ‘traditional’ shrimp culture, which generally brings revenue in the range IDR 1–5 million per ha per crop with 2 crops per year.

Restored pond use

Prior to the adoption of Caulerpa culture, these ponds were either not in use or were used for very limited grow-out of, for example, undersized swimming crabs caught from the wild. Now these ponds are providing a useful contribution to the village.

The house that lawi-lawi built. Parigi Daeng Bella 

made enough profit in his first year of farming Caulerpa 

to buy a new motorcycle and build a new house

for his family.

Environmental benefits

Caulerpa culture has no deleterious environmental impacts, and the plants absorb nutrients from local waters, contributing to better water quality.

Market

One potential disadvantage to Caulerpa culture is that the market is local and in probably limited in volume. To check this we are planning to conduct market studies in collaboration with Hasanuddin University. Although there is good demand for edible seaweed in countries such as Japan and Korea, it remains to be seen whether South Sulawesi farmers can access these markets.

Nana S.S.U. Putra 

is with the Ministry of

Marine Affairs and Fisheries,

 Directorate General of Aquaculture,

 South Jakarta.

Email : nana_ssup@yahoo.com.

Further R&D

To support the Laikang Caulerpa farmers, BADC Takalar and project partners, particularly the University of Sydney and Hasanuddin University, are continuing to undertake specific research activities into aspects of Caulerpa culture. Hasanuddin University is undertaking a study of market capacity, to evaluate to what extent market is likely to limit production of Caulerpa. Caulerpa, like other macroalgae, concentrates metals in the plant tissue. Together with researchers from the State University of Makassar we are currently evaluating the metal content of Caulerpa sampled from the ponds to see whether this is likely to produce any significant food safety issues.

Acknowledgments

Imran Lapong and Mike Rimmer 

are with the Australian Centre for International

Agricultural Research Field Support

Office, Makassar, South Sulawesi.

Rimmer is also with the Faculty of

Veterinary Science, University of Sydney,

Australia.

We thank Dr Mardiana E. Fachri, Faculty of Marine Science and Fisheries, Hasanuddin University, Makassar, for her assistance with development of the farmer group at Laikang, and Prof. Alan Millar, principal research scientist, Royal Botanic Gardens Sydney, for Caulerpa identification. We thank ACIAR for funding this research. This article is an output of ACIAR project FIS/2007/124 ‘Diversification of smallholder coastal aquaculture in Indonesia’.

Sugeng Raharjo 

is with the Brackishwater Aquaculture Development Centre, Takalar,

South Sulawesi. 

January/February 2013 AQUA Culture Asia Pacific Magazine | 45