Identification:
This species is the largest individual size among the Panulirus lobsters. The body length (excluding antennae) can reach up to 50 cm (4-4.5 kg/individual), with a common size of 30-35 cm (1.5-1.8 kg/individual). The carapace is smooth and exhibits a sea-green color with leafy tones. Spines on the cephalothorax are orange, excluding the white cheek spines. A horizontal band of black or dark brown runs across the dorsal surface of the abdominal segments, and there are one or two pairs of cream or bright white spots on the sides of each abdominal segment. The basal segment of antenna I has four spines arranged in a square, with the two anterior spines being larger. The third maxilliped lacks an external branch. The dorsal surface of the abdominal segments is smooth, lacking grooves or any trace of them.
Biology and Ecology:
This species inhabits depths ranging from 1 to 50 meters, most commonly found in shallow coastal waters with low visibility, at depths of 1-8 meters. They typically hide in rocky crevices with sandy or silty substrates near river mouths or on coral reefs. They are solitary, not forming groups, and only pair up during the breeding season. Annually, along the coastal provinces of central Vietnam, from December to July-August of the following year, juvenile lobsters (with a carapace length of 8-25mm) tend to congregate in rocky areas along the coast and islands, peaking from December to January-February of the following year. The ornate spiny lobster ( Panulirus ornatus) exhibits the fastest growth rate among the Panulirus lobsters. With a stocking density of 10-15 individuals/m² and a diet of fish, small crustaceans, mollusks, and sea urchins, juvenile lobsters weighing 50-100 grams can gain approximately 15-25 grams per individual per month.
Distribution:
- Vietnam: Very common in Vietnam, with the highest concentrations found in the coastal provinces of central Vietnam.
- Global: Indo-West Pacific: Japan, Solomon Islands, Papua New Guinea, southwestern, western, northern, northeastern, and eastern Australia, New Caledonia, Fiji, Red Sea and East Africa, eastern Mediterranean.
Value:
This species has scientific and aesthetic value.
Status:
Before 1975, lobsters of 1.5-1.8 kg/individual were very common. This species yields the highest harvest among the Panulirus spiny lobsters. Since 1990, due to strong export demand, the annual harvest has increased significantly, leading to a noticeable decline in numbers, potentially by 20%, with the population of mature individuals fluctuating dramatically. The distribution area has also been continuously reduced, estimated to be below 20,000 km². Recently, the wild juvenile lobster population has been increasingly exploited to supply the growing lobster farming industry in the coastal provinces of central Vietnam.
Assessment:
VU A1d B2a+3d (Vulnerable).
Conservation Measures:
This species was included in the Vietnam Red Book (1992-2000). It is necessary to reduce the intensity of juvenile lobster harvesting and implement rotational harvesting locations. Investment is needed in research to address ecological, physiological, and population biological issues from juvenile to sexual maturity to refine farming techniques and ensure sustainable harvesting.