Humpback Grouper Culture (Cromileptes altivelis)

Site Selection

The culture site has to be protected from high waves and a ratting wind. Also, the site is expected to have more thab 10 m water depth. Freshwater from rivers or rainfalls and drain waters from shrimp culture farms oar factories should not flow in the site.

Facilities Preparation

The suitable size of a net cage frame is 4 x 4 m. Usually, one raft is composed of four net cages. Several net cages with different mesh and cage sizes have to prepared.

Suitable net cages in each fish stage

Seed Procurement

Juveniles (4 - 10 cm TL) bred in hatcheries are available as seed almost all year round in Indonesia (more than 1 million seeds in 2001). Seed suppliers exist in North Bali, Lampung, East Java (Situbondo). The price of seed is Rp. 4,000 - 10,000 per piece of 4 - 10 cm TL. It is strongly advised to choose good quality seeds. Seed can be safely transported using oxygenated plastic bags or live tanks throughout Indonesia.

Fish Stocking

High fish stocking density often causes slow growth and high mortality in culture fish. It is recommended to maintain fish densities of less than 2 kg/m3 for fish under 10 g BW, and 7 kg/m3 for bigger fish.

Feeding

Trash fish can be used as food. However, there are difficulties in this method as follows:
- inconstant supply of trash fish
- intense work for preparation
- unstable food quality
- high investment (a freezer)
- easy pollution in the area
To prevent nutritional deficiency, trash fish should be mixed with vitamins before feeding. Juveniles reared with trash fish hardly tke dry pellets. To culture the grouper with the pellets, it is necessary to secure seed already weaned on to the pellets.

Comparation of foods

Feeding method for the grouper with dru pellets

When the cultured fish are in stress condition like after handling (for net changing, transfer) and during harsh climate, it is recommended to enrich the pellets with vitamin C at a dosage of 0.5 - 1 g/kg feed.