Identification:
Large shrimp, with a body (excluding antennae) reaching up to 30 cm in length (weighing 1.4 – 1.5 kg per individual). The average size is 20 – 25 cm (0.7 – 0.8 kg per individual). Female shrimp that spawn for the first time are around 17 cm. The shell is rough, and its color varies from a slightly grayish-green to reddish-brown. The spines on the cephalothorax are reddish-brown or white. Small, scattered yellow or white spots are present on the dorsal side of the abdominal segments, forming a border along the posterior margin of each segment. The third maxilliped (leg-like appendage near the mouth) lacks an exopod (an external branch). The basal segment of the first antenna has four equal-sized spines arranged in a square. The dorsal side of abdominal segments II-IV has a continuous or discontinuous transverse groove, and the anterior margin of the groove is divided into numerous small lobes.
Biology and Ecology:
This species typically inhabits sandy-muddy bottoms, sheltering in rock crevices in coastal waters, at depths of 1-5 meters, with wave action. They often live in groups of 3-4 individuals and are most active at night. The breeding season is from approximately April to June, peaking in May. From December to June of the following year, juvenile shrimp (with a carapace length of 8-20 mm) often congregate around coastal reefs and islands.
Distribution:
- Within Vietnam: Found throughout the coastal waters of Vietnam, from the North to the Gulf of Thailand, with the highest concentrations in the coastal provinces of the Central region.
- Worldwide: Found in the Indo-West Pacific region, including waters off Japan, Indonesia, Australia, and East Africa.
Value:
This species holds scientific value and can be farmed commercially.
Status:
Prior to 1975, shrimp of 0.7 – 0.8 kg per individual were very common in coastal waters and around islands. After 1975, particularly since 1990, the population has significantly declined, potentially by 50%, due to increased exploitation for export. Furthermore, the development of aquaculture has led to coastal water pollution, and the use of explosives for fishing has damaged and reduced habitats, possibly by up to 20%. In the last 10 years, juvenile shrimp have been intensively harvested to supply the expanding cage-rearing industry in the Central provinces.
Classification:
EN A1c,d B2b+3d.
Conservation Measures:
Listed in the Vietnam Red Data Book since 1992. Recommendations: Reduce the intensity of fishing; research the impact of juvenile shrimp harvesting for cage culture on wild shrimp populations; prohibit fishing during the breeding season; strictly ban dynamite fishing and coral harvesting.