This research aims to minimize the environmental impact and promote the sustainability of aquaculture by optimizing nutrient dynamics, improving water quality and enhancing species growth performance through a land-based Integrated Multi-Trophic Aquaculture (IMTA) system. The study focused on Black Sea trout (Salmo labrax), Mediterranean mussel (Mytilus galloprovincialis), and sea lettuce (Ulva lactuca), reared in interconnected tanks using Black Sea water over 90 days. The Black Sea trout more than doubled in size to 333.92 ± 6.60 g and significant improvements were observed in the specific growth rate (SGR) at 0.85% and the feed conversion ratio (FCR) at 1.38. The fish's proximate composition included 19.19% protein, 2.31% lipid, 70.35% moisture, and 1.34% ash, with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels at 6.06% and 13.50%, respectively. The macroalgae showed substantial growth, with a SGR of 0.34% and a weight gain of 310 ± 3.50 g. Additionally, it increased protein content by 13.41% and demonstrated significant nutrient removal efficiencies: 41.4% for nitrate, 66.7% for nitrite, and 90.8% for ammonia. EPA and DHA levels increased by 45% and 70%, reaching 4.66% and 2.19%, respectively. In contrast, the mussels experienced a weight loss, with a weight gain of -1.20 ± 0.00 g and an SGR of -0.20%. Initially, wild mussels had a composition of 77.56% moisture, 13.79% protein, 1.54% lipid, and 1.77% ash. The presence of mussels and macroalgae significantly improved water quality, notably reducing ammonia by 92.2%, nitrate by 44.6% and nitrite by 75%, benefiting the overall ecosystem. This study concludes that a land-based IMTA system enhances sustainable aquaculture by improving product quality and bioremediation, with macroalgae playing a crucial role in nutrient absorption and growth within the system.

The aim of the present study was to investigate the effects of seasons (summer and winter) on the proximate, amino acid and fatty acid compositions of gilthead sea bream fish fed with commercial diets in sea cages and earthen ponds in the Aegean Sea in Türkiye. In general, the nutrient composition of the diets met the nutritional needs of the fish. Proximate analysis of fish fillets revealed that fish reared in earthen ponds had the lowest moisture and highest lipid content in the winter season (p < 0.05). Although fillet protein contents were comparatively higher in the winter (p < 0.05), there was no significant difference between systems in the same season (p > 0.05). Growing gilthead sea bream in marine cages produced fillets with high contents of the essential fatty acids (EFA) eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). On the other hand, the 18:1n-9 and 18:3n-3 contents of fish reared in earthen ponds increased by 25.64 and 18.80% respectively, compared to those in marine cages. Fillet content of total n-3 fatty acid were comparatively higher (p < 0.05) in gilthead sea bream from marine cages, and this increase was even more evident in the winter months. The n-3/n-6 ratios of fillets were significantly high in gilthead sea bream from marine cages in the summer. The levels of the essential amino acids (EAAs) arginine and leucine were higher in fillets from both systems in the winter. On the other hand, fillet contents of lysine were higher in the summer. In general, the total EAA content of fillets was higher in fish from the sea cages in summer. EAA/NEAA ratios in both systems in summer and winter were found to be at good levels in terms of fish fillet quality. Fillet contents of EFA and EAA from both systems and seasons were found to be good for human consumption and will have positive effects on human nutrition. In conclusion, commercial diets used in feeding gilthead sea bream improved the proximate, fatty acid and amino acid compositions of fillets to a good extent. Different seasons and culture systems may affect the nutritional composition of fish fillets, especially on fillet EFA contents. Results of fillet samples in marine cages and earthen ponds in summer and winter showed that the fish were of good quality for human health. Evaluation of the results in the present study shows that that gilthead sea bream can also be successfully cultured in earthen ponds in areas unsuitable for agriculture.

This study examines the nutritional profile of European flat oysters ( Ostrea edulis ) cultivated in an Integrated Multi‐Trophic Aquaculture (IMTA) system in Gaeta, Italy. Oysters were deployed for 257 days, 8 July 2023–21 March 2024, at two distances from gilthead seabream ( Sparus aurata ) cages: 20 m, representing high exposure to fish‐derived waste, and 800 m, reflecting reduced waste influence and greater phytoplankton availability. The objective was to evaluate how proximity to fish cages, combined with seasonal variability, influences oyster nutritional quality and to identify optimal spatial arrangements in IMTA systems. Sampling occurred in summer, autumn, winter, and spring to capture seasonal changes in physiology and nutrition. Oysters at the distant site showed consistently higher nutritional quality, attributed to greater phytoplankton access and dilution of fish waste. Crude protein content ranged from 4.49% to 7.81%, with the highest values recorded at the distant site. Crude lipid levels peaked at 1.31% in March, linked to prereproductive nutrient accumulation. Arginine and lysine were the most abundant essential amino acids (EAAs), with significantly higher arginine levels at the distant site during late autumn and early spring. These findings emphasize the spatial planning and seasonality in IMTA, supporting sustainable aquaculture, ecosystem services, and nutrient‐rich seafood production.

This study evaluated the effects of three feeding regimens—commercial feed (CF), minced trash fish (MTF), and a 50:50 mixture (MIX)—on the growth performance and tissue composition of the blue crab (Callinectes sapidus) reared in a recirculating aquaculture system (RAS). A total of 96 crabs (8 per tank, four tanks per group) were fed daily at 3% of body weight. Growth was assessed via weight gain, carapace width (CW), and carapace length (CL), while biochemical analyses focused on lipid, fatty acid, and amino acid profiles. The CF and MIX groups exhibited significantly higher final body weights (115.64 ± 3.03 g and 113.53 ± 2.53 g, respectively) and CW (97.88 ± 1.02 mm and 97.16 ± 0.43 mm) compared to the MTF group (p < 0.05), suggesting more frequent or complete molting. The MTF group showed limited growth (102.81 ± 2.25 g; 95.24 ± 1.19 mm), likely due to reduced ecdysis events. Tissue lipid and fatty acid profiles reflected dietary inputs, with significant differences in DHA/EPA and n-3/n-6 ratios among treatments (p < 0.05). Essential amino acid levels decreased across all groups, possibly due to the metabolic demands of molting. These findings highlight the critical role of diet in promoting molting and improving tissue quality in blue crab aquaculture under controlled RAS conditions.