Identification:
A large crab species, with a body length reaching up to 25 cm. The carapace is longer than wide, with the dorsal surface densely covered in tubercles that project forward. The frontal region features three triangular teeth. The sides of the carapace each possess a plate, divided into three teeth on the upper margin.
The eye sockets are deep, with three sharp teeth on the upper margin. The second antennal segment (antennal peduncle) is large and covered in numerous granules. Two prominent lobes are present outside the eye socket, each with three teeth. The chelipeds (claws) are equal in size and robust. The carpus (wrist) segment bears a sharp spine near the anterior margin. The merus (thigh) segment has two teeth at the posterior apex. The outer surface of the propodus (palm) has short hairs, with two spines on the upper ridge and five triangular teeth on the lower ridge. The walking legs are paddle-shaped.
Biology and Ecology:
Typically inhabits marine environments with stable salinity, on sandy bottoms, at depths of 8–50 meters.
Distribution:
- Within Vietnam: Found throughout the coastal waters of Vietnam, but predominantly in the Central region.
- Global: Japan, China, Australia, India, Sri Lanka, and Africa.
Value:
Of scientific value and important for ecological research.
Conservation Status:
Prior to 1975, this species was commonly encountered along the Central coast of Vietnam. Since 1975, particularly from 1990 onwards, increased harvesting has significantly reduced the population, with an estimated decline of over 20%. The pre-1975 distribution area was estimated to be greater than 20,000 km². Due to intensive fishing, the current distribution area has shrunk to approximately 10,000 km².
Assessment:
VU A1c,d+2c,d B2a+3a,d. (Vulnerable)
Conservation Measures:
Should be included in the list of protected species by the Department of Fisheries and alternating fishing locations should be implemented.