Identification
Appearance:
A large crab species. The carapace can reach up to 12 cm in width and exhibits a reddish-brown coloration, with a distinctive cross-shaped marking on the surface. The anterolateral margin of the carapace features six teeth. The first tooth, also known as the outer orbital tooth, is slightly curved inward and has a slightly concave middle section. The sixth tooth projects outwards, forming a spine-like structure. The posterolateral and posterior margins are obtuse (blunt). The frontal region (between the eyes) has six teeth; the two central teeth are relatively large, while the first lateral tooth is broad but shorter than the second lateral tooth.
Biology and Ecology
Habitat:
Found in coastal marine environments at depths of 10-30 meters, primarily inhabiting substrates composed of rock, sand, and coral.
Distribution
Vietnam:
Distributed throughout the coastal waters of Vietnam, but predominantly found in the central region.
Global:
Occurs in Japan, Indonesia, China, Malaysia, Singapore, Thailand, Australia, India, and East Africa.
Value
Economic Importance:
This species is valued for its use as a food source.
Conservation Status
Population Trends:
Prior to 1975, while present throughout Vietnam’s coastal waters, it was most commonly observed in the central region. Since 1975, and particularly after 1990 due to increased harvesting, the population of this species has experienced a significant decline, potentially exceeding 20%. The species’ distribution covered an area of approximately 20,000 km². Due to intense fishing, the occupied area has shrunk to approximately 10,000 km².
IUCN Classification:
VU A1c,d B2a + 3a (Vulnerable)
Conservation Measures
Recommendations:
This species should be included in the list of protected species by the fisheries sector. Conservation efforts should also focus on reducing fishing intensity and implementing rotational fishing practices.