The shrimp species cultured in Asian countries belong to two genera (Penaeus and Metapenaeus) of the family Penaeidae. Among the dozen species cultured, Penaeus monodon, P. japonicus, P. merguiensis, P. indicus, P. orientalis and Metapenaeus ensis are the more important ones.
The aquafarming techniques of P. japonicus have been well established in Japan and Taiwan. The spawners are readily obtained in large numbers from the wild. The shrimp is hardy and can withstand handling. The survival rate of adult shrimp for long distance transportation is high. However, the species cannot tolerate low salinity and high temperature. P. japonicus prefers sandy bottom in grow-out ponds and grow fasts in high protein (about 60%) diet feed. The other temperate species, P. orientalis which is being cultured commercially in China and Korea, has a single pronounced spawning season in spring. Since both are temperate species, the period of hatchery operation is limited to the warmer seasons only.
Known as tiger or jumbo shrimp, P. monodon is the most common species in Southeast Asian countries. It is one of the fastest growing species among the various shrimps tested for culture. In pond conditions, shrimp fry of about 1 g in weight grow to a size of 75–100 g in five months at a stocking density of 5,000 per hectare. Some were able to grow them to 25 g in 16 weeks in tanks stocked at 15/m2 ; others grew them to 42 g in 210 days in earthen pond and to 35 g in three months in tanks stocked at 15/m2 . The tiger shrimp is a euryhaline species and grows well in salinities ranging from 15 to 30 ppt. It is hardy and not readily stressed by handling. Presently, the major supply of fry is still from the wild but the supply is sparse. Although several hatcheries have been established notably in the Philippines. Taiwan and Thailand, fry production is not consistent due to the full dependence on spawners caught from the wild. Until broodstock in captive condition can be made to mature and spawn, hatchery production of this species still has to depend on wild supply of spawners.
The biological characteristics of both species are generally the same. Many fish farmers are not able to distinguish the two species from each other. There are behavioral differences which help easy distinction. P. indicus prefers sandy bottom and is difficult to harvest by draining the pond while P. merguiensis is found most frequently in ponds with muddy bottoms moving out of the pond readily when water is drained. Gravid females of these species are easily obtained in large quantities from the wild. They can also mature in captivity. The larvae are more easily raised than those of P. monodon. However, the larvae are less hardy than other species, the juveniles and adults cannot withstand rough handling. Large quantities of fry can be obtained from natural spawning grounds. The growth rate in pond is relatively fast, reaching 12–15 g within the first three months of culture.
The species is very tolerant to low salinity (5–30 ppt) and high temperature (25–45°C). Fry are abundant in natural spawning ground and their survival rate in the ponds is usually high. This shrimp usually does not grow to a large size and has a low market price compared to other species. They are largely produced from trapping ponds or as secondary species of shrimp farms.
