KETUT SUGAMA AND ISTI KOESHARYANI
The new era for grouper hatchery production has been developed and current production of grouper fingerlings has increased rapidly. Most cage farms prefer to grow fingerlings of humpback grouper, tiger grouper, hybrids and coral trout grouper. Those groupers have a good market price and the demand as live fish also commands a high price.
Indonesia’s grouper hatcheries grew rapidly from the late 1990s. The initial success was achieved in 1999 with the breeding of humpback groupers Cromileptes altivelis (Sugama et al. 1999), followed by tiger grouper Epinephelus fuscoguttatus, and flowery grouper E. Polyphekadion (2001), estuarine grouper E. coioides, coral grouper E. Corallicola, potato grouper E. tukula (2005), giant grouper E. Lanceolatus (2008), coral trout Pletropomus leopardus, blacksaddled coral grouper Plectrophomus laevis (2010) and also grouper hybrids, such as male E. Lanceolatus xfemale E. Fuscoguttatus and female E. Fuscoguttatus x male flowery grouper E. Polyphekadion (2012) (Sugama et al. 2012).
The new era for grouper hatchery production has been developed and current production of grouper fingerlings mentioned above has increased rapidly. Most cage farms prefer to grow fingerlings of humpback grouper, tiger grouper, hybrids and coral trout grouper. Those groupers have a good market price and the demand as live fish also commands a high price.
Egg production is no longer a bottleneck; there are 22 hatcheries ( 7 public and 15 private) in Gondol, Bali, Indonesia actively producing fertilized eggs of various groupers. However, larval rearing, especially the early nursery phase, still faces problems with survival less than 10 percent for coral trout grouper compared to other groupers (Su et al. 2008) and other marine fish (Yoseda et al. 2006, Nakai 2007). Mortality during the early larval stage of 2-6 days after hatching (DAH) can be a results of bad egg quality, food availability (type, quality and quantity) and environmental factors such as water quality and light intensity.
Our experience with research and development of mass seed production of groupers indicates that the factors contributing to larval mortalities are poor quality of newly hatched larvae, failure of initial feeding, trapping of larvae in surface water from surface tension, secretion of sticky mucus, long spines, cannibalism, uninflated swim bladders and viral diseases suuch as nervous necrosis virus (NNV) and Iridovirus.
After numerous experiments, better and more consistent survival of grouper fingerling of more that 30 percent was achieved, except for coral trout groupers, which remains low (<10 percent) (Sugama et al. 2012). The techniques of grouper seed production developed by the Institute for Mariculture Research and Development (IMRAD) at Gondol, Bali, has been widely adopted by the private sector. This article reviews the advanced technology of grouper seed production run by private-sector hatcheries and experiences in transferring technology to them.
Advances In Broodstock Management And Egg ProductionBroodstock management requires that biological characteristics are understood and used to create a culture environment to enable the fish to reach advanced stages of maturation (Rimmer et al. 2004). Once protocols to achieve adequate spawning have been established, aspects of reproduction and genetic traits of the broodstock need to be managed to ensure the progeny have improved characteristics for ongrowing and market. Most grouper broodstock are artificially produced from hatcheries and reared in marine cages until they attain mature size and then are moved to spawning tanks. The smallest size of mature female and male groupers are presented in Table 1. Groupers are protogynous hermaprodites, meaning that they matureas females then change to males at a later age (Sugama et al. 2001)