<span lang="EN">Temporal water-quality variability and its implications for environmental management of sand lobster aquaculture

BACKGROUND AND OBJECTIVES: Sustainable management of sand lobster aquaculture is often limited by monitoring approaches that summarize environmental conditions using long-term averages, obscuring short-term extremes and spatial variation. The study objectives were to characterize how water quality varies with depth and time at a floating net cage aquaculture system, identify the physical drivers underlying that variability, determine whether longitudinal growth reflects culture duration, initial size, and stocking density more than environmental exposure alone, and translates these relationships into a transferable environmental monitoring architecture. METHODS: The study collected longitudinal growth and environmental data from floating net cage culture in Indonesia. Monitoring covered temperature, salinity, oxygen concentration, potential of hydrogen, and nutrient concentrations across three water depths and multiple sampling times. A non-parametric statistical comparison evaluated dissolved oxygen differences among depths, and correlation and regression analysis assessed how wind speed relates to temperature and dissolved oxygen. Multivariate statistical ordination summarized dominant environmental gradients, and mixed-effects statistical models, compared through an information-theoretic model selection approach, captured longitudinal growth. FINDINGS: Dissolved oxygen concentration differed significantly among depths (test statistic ۲۹.۲۷, probability below ۰.۰۰۱), declining by close to a fifth from the surface to three and ten meters. Monthly wind speed tracked the concurrent decline in temperature closely (correlation coefficient -۰.۹۸۸, probability below ۰.۰۰۲) and showed no statistically significant association with dissolved oxygen, consistent with a wind-driven transition observed within this single production cycle. Culture duration, initial size class, and stocking density together explained total length best, with an additive model carrying more than seventy percent of the statistical weight among six candidate models. Growth rate showed its strongest association with low-oxygen exposure, followed by temperature and potential of hydrogen condition, interpreted cautiously given the limited independent exposure intervals available. CONCLUSION: Successful sand lobster aquaculture requires an adaptive environmental monitoring architecture that accounts for depth-related oxygen stratification and wind-driven seasonal variability, alongside coordinated management of culture duration, initial seed size, and stocking density. The analytical architecture of lobster integrated site assessment and management is transferable to other marine aquaculture systems by incorporating species-specific biological indicators and management variables.

کلیدواژه ها:

Adaptive aquaculture management ، Biomanagement ، Environmental monitoring architecture ، oceanographic variability ، Panulirus homarus ، Sustainable aquaculture.