Herno Minjoyo, M.Sc. is a Chief Engineer at the Marine Aquaculture Research Center, BRIN, Indonesia. He holds a Master's degree in Marine Biology from the University of the Philippines and has over 40 years of experience in marine aquaculture, fish nutrition, lobster culture, shrimp farming, and marine fish hatchery technology. He has led numerous research and technology development programs, holds several aquaculture-related patents, and has published more than 30 scientific papers in national and international journals. His work focuses on advancing sustainable aquaculture technologies and marine resource development.

Influence of Stocking Density on the Biological Performance of Spiny Pearl Lobster (Panulirus ornatus Fabricius, 1798) Cultured in Submerged Cages.                                                         A growth-out experiment on the spiny pearl lobster (Panulirus ornatus) was conducted from August to October 2022 to evaluate biological performance and physiological responses under different stocking densities. The study was carried out using cylindrical HDPE hanging cages submerged at a depth of 7 m below sea level, where ambient water temperatures ranged from 29 to 32°C. Juvenile lobsters with an initial body weight of 130–140 g were stocked at three density levels: 5 lobsters/m² (Treatment A), 10 lobsters/m² (Treatment B), and 15 lobsters/m² (Treatment C), with each treatment replicated three times in a completely randomized design (CRD). Lobsters were fed daily with green mussels or fish meat at a feeding rate of 5% of their body weight. The results showed that the highest specific growth rate (SGR) was achieved in Treatment A (5 lobsters/m²), which was significantly higher (P < 0.05) than those recorded in Treatments B and C. Physiological assessment based on total hemocyte count (THC) in the hemolymph revealed that lobsters reared at the lowest stocking density exhibited significantly lower THC values compared to those stocked at higher densities, indicating reduced physiological stress. Overall, the findings demonstrate that a stocking density of 5 lobsters/m² provides optimal conditions for growth and physiological stability of P. ornatus cultured in submerged cage systems.                                                                                               Keywords: Spiny pearl lobster, growth, stocking density, 7 m depth