Aquaculture Journal

Controlled environment agriculture technologies are traditionally applied to higher plants to enhance growth and cultivation periods, but such a concept has seldom been applied to seaweed aquaculture. A new dimension has been opened, wherein preliminary investigations in Ulva ohnoi revealed that continuous exposure (24 h) of light modulates chlorophyll-a fluorescence, carbohydrate content, and biochemical composition affecting the daily growth rate. DGR (daily growth rate) increased 2.6 times under continuous illumination for 24 h compared to the 12 h L/D photoperiod. Mg and carbohydrate contents were raised by 1.1 and 1.2 times, respectively, under continuous illumination. DGR formed a strong positive correlation with carbohydrate, protein, carotenoid, chlorophyll-a fluorescence, C, H, and Mg levels. A short cultivation cycle (15 days) was proposed to enable a consistent, continuous high growth and to avoid the induction of reproduction. The feedstock demand for bio-products, aquaculture feed, biomaterials, functional food, and food additives is registering unprecedented feedstock demand for Ulva. However, further detailed studies are desired to understand the seasonality and economic viability of scaling up this technique for commercial implementation.

Accurate prediction of shrimp body weight is critical for optimizing harvest timing, feed management, and stocking density decisions in intensive aquaculture. While prior studies emphasize environmental factors, operational management variables—particularly harvesting metrics—remain understudied. This study quantified the predictive importance of harvesting-related variables using 5 years of industrial-scale operational data from 12 ponds (5479 cleaned records, 34.94% retention rate). We trained seven machine learning models and applied three independent feature importance methods: consensus importance ranking, SHAP explainability analysis, and Pearson correlations. Main findings: Operational variables (days of culture: 2.833 SHAP, stocking density: 1.871, cumulative feed: 1.510) ranked substantially above environmental variables (temperature: 0.123, pH: 0.065, dissolved oxygen: 0.077). Partial harvest frequency showed bimodal clustering, indicating two distinct viable operational strategies. The Weighted Ensemble model achieved the highest performance (R² = 0.829, RMSE = 4.23 g, MAE = 3.12 g). Model stability analysis via 10-fold GroupKFold cross-validation showed that the Artificial Neural Network (ANN) exhibited the tightest confidence bounds (0.708 g width, 27.7% coefficient of variation), indicating exceptional consistency. This is the first study to systematically analyze the importance of harvesting variables using SHAP explainability, revealing that operational management decisions may yield greater returns than marginal environmental control investments. Our findings suggest that operational optimization may be more impactful than environmental fine-tuning in well-managed systems.

The Indonesian coastline holds significant potential for aquaculture but is increasingly vulnerable to climate change impacts such as land subsidence, salinization, and floodings. Ensuring stable income for local communities is essential, especially during extreme events like King Tides, which cause extensive floodings. This study assessed the productivity and economic returns of an agaroid seaweed monoculture compared to co-cultivation with Giant tiger prawn, Milkfish, and Barramundi during a King Tide. The experiment was conducted in conventional ponds with seaweed monoculture or combined with one of the three other commodities. The experiment ran from May until October in 2022 and was performed in triplicate. Floodings equalized water parameters. The results demonstrated that all systems provided stable income, with co-cultivation increasing profitability. Average revenues per hectare were USD 777 (seaweed monoculture), USD 832 (with shrimp), USD 1622 (with Milkfish), and USD 2014 (with Barramundi). Agar content was significantly higher in the seaweed monoculture, and gel strength was found to be significantly higher in the seaweeds co-cultivated with shrimp and Milkfish. Total agar production did not differ between the treatments. These findings suggest that integrated aquaculture systems can enhance income resilience while supporting food security in climate-impacted coastal zones. The approach offers a promising strategy for combining livelihood stability with adaptive coastal management and reduced environmental impact but needs to be tailored to local conditions.