WP/81/SPH/CP-21
by
Sukotjo Adisukresno1
1. INTRODUCTION
Macrobrachium rosenbergii culture is still in the introduction stage in Indonesia, even if it was initiated a few years ago. The farmers are not confident yet on the benefit of prawn culture, even if the price of consumable size is promising. To promote this type of aquaculture, the government constructed several prawn hatcheries in this country to fill the prawn fry requirement. There are around 25 000 ha of freshwater pond in Java which are traditionally for the culture of carp, Puntius, giant gouramy, kissing gouramy and other common freshwater species. This areas might be used for the combined culture with prawn as a new commodity which might increase their income.
2. LOCATION OF PRAWN HATCHERIES
All of the prawn hatcheries are located in Java where freshwater culture ponds have been established.
These hatcheries are located in:
All of these hatcheries are under the technical assistance of the Brackishwater Aquaculture Development Centre (BADC), Jepara.
3. FACILITIES
The three hatcheries namely Adiraja, Prigi and Pangandaran have the same facilities, that is:
Adiraja hatchery pumps saltwater from the estuary during high tide, while the others pump directly from beach wells.
4. LARVAL REARING METHOD
The green water system is applied for the hatchery operation. Big tanks for larval rearing are stocked at density of around 20 larvae per liter. Prepared food (Adisukresno, 1975) and small amount of Artemia nauplii are fed as the daily consumption for the larvae. Left over food and debris are siphoned out every day.
5. PRODUCTION
On the basis of survival rate, only BADC, Jepara produce an average over 50 percent, while the other hatcheries are still very poor, with around 10 percent. The main reason given is the failure of the green water culture and the bloom of diatoms.
The BADC Jepara is not concentrated on Macro-brachium hatchery operation alone but anyhow it produced around 3–4 millions postlarvae which were distributed freely to the farmers, while the other hatcheries produced 0.5–1.5 million of postlarvae per year.
1 Director, Brackishwater Aquaculture Development Centre, Jepara, Indonesia
Most of the prawn hatcheries produce very well during the dry season (June-October). In this season, no farmers want to culture prawn in their ponds, since the water supply is getting poor. During dry season, the green water as the culture medium for larvae is easier for production compared with the rainy season.
6. DISCUSSION
Since Macrobrachium rosenbergii is promising to culture in the country, the government should take more action to promote the prawn culture through the extension workers. The farmers actually want to culture Macrobrachium as long as the seed supply is available on time as required. When the farmers realize that this culture is profitable, the demand of fry will increase and the farmers and private sector will be interested to construct Macrobrachium hatcheries.
Table 1 gives the latest results of Macrobrachium fry production by the Brackishwater Aquaculture Development Centre at Jepara. Six larval rearing tanks measuring 6×1.5×0.9 m each are constructed under glass roofing for use in the larval rearing. To reduce the excess illumination from the sun, the ceiling is provided with wood bars of 5 cm wide with intersect of 5 cm. For aeration, each tank is provided with 12–16 airlifts. There is no particular reason on technical point of view for the use of airlift, but this was done because the blower does not have enough pressure if air stones are set at the bottom. Prepared feed (Adisukresno, et al, 1975) was fed to the larvae and Artemia nauplii from 10 g cyst was fed to each tank everyday. The rearing period varies from 30 up to 40 days.
Table 1.
Macrobrachium rosenbergii larval rearing in the concrete tanks1 and the number of juveniles
produced during the period of April-November 1981 at the
Brackishwater Aquaculture Development Centre, Jepara, Indonesia
| No. of larvae stocked | Density per liter | No. of juveniles produced | Survival rate(%) | |
| April 1981 | 116 000 | 18.1 | 60 000 | 51.7 |
| May | 120 000 | 18.8 | 102 000 | 85.0 |
| May | 135 000 | 21.0 | 53 500 | 39.6 |
| June | 115 000 | 17.9 | 65 000 | 56.5 |
| June | 206 000 | 32.2 | 87 000 | 42.2 |
| June | 121 000 | 18.9 | 85 000 | 70.2 |
| July | 322 000 | 50.3 | 105 000 | 32.6 |
| July | 262 000 | 40.9 | 106 000 | 40.5 |
| August | 134 000 | 21.3 | 107 000 | 79.9 |
| August | 69 000 | 10.9 | 33 000 | 47.8 |
| September | 146 000 | 23.2 | 75 000 | 51.4 |
| October | 150 000 | 23.8 | 111 000 | 74.0 |
| October | 319 000 | 50.6 | 85 000 | 26.6 |
| November | 209 000 | 32.6 | 63 000 | 30.1 |
