A novel two‐stage seaweed integrated multi‐trophic aquaculture

Abstract

Marine aquaculture is undeniably a key future direction for the production of food. However, traditional aquaculture involves some significant drawbacks, the major one of which is the surplus discharge of organic matter and dissolved nutrients. To mitigate the environmental impact, integrated multi‐trophic aquaculture (IMTA) systems, which advocate the integration of fed fish with inorganic and organic extractive species, may offer a sustainable solution. This study focuses on an innovative experimental setting, integrating three marine macroalgae species (Ulva rigida, Gracilaria conferta, Hypnea musciformis) serially connected via two‐stage seaweed culture tanks to a finfish culture (the gilthead sea bream; Sparus aurata). The aim was to compare and assess the biofiltration and growth performances of the seaweeds, while altering their order in the two‐stage system. The results indicated U. rigida as the fastest growing species. Ulva rigida also displayed the highest total ammonia nitrogen (TAN) uptake rates and removal efficiency. The design allowed the production of high tissue protein and carbohydrate levels for potential biorefinery uses. Ulva rigida protein content averaged 23%, while that of H. musciformis and G. conferta averaged 25% and 18%, respectively. Hypnea musciformis and G. conferta grown under low nutrient conditions presented a significantly higher total carbohydrate content of nearly 50%, compared to 34% exhibited by U. rigida. In summary, the seaweed pairing in a two‐stage system did not inhibit the performance of each individual species and improved overall production. Consequently, it offers significant advantages for future IMTA systems.

Successful Approaches for a Red Seaweed Biorefinery

“…Red seaweeds may be used in intact dried form as protein sources in food and feed and the bioactive peptides have diverse actions, such as immunomodulatory, antibacterial, antithrombotic, and antihypertensive effects [19,20]. Seaweed biomass produced with aquaculture effluents contain 2–4-fold more protein than that that grown in wild cultures, because seaweeds assimilate the fish effluents, which are rich in dissolved ammonia and phosphate [21].…”

Valuing Bioactive Lipids from Green, Red and Brown Macroalgae from Aquaculture, to Foster Functionality and Biotechnological Applications

“…The world production of marine macroalgae has more than tripled, up from 10.6 million tons in 2000 to 32.4 million tons in 2018 [ 10 ]. Some edible macroalgae species are well-suited for marine aquaculture production [ 11 , 12 ], to be included in healthy and sustainable diets, and labeled as organic products [ 13 ]. Novel foods with health benefits are more attractive for consumers, as revealed by a preference study on Italian consumers, where 76% were willing to eat macroalgae [ 14 ].…”

Cultivation of early life history stages of Porphyra dioica from the British Isles

“…The mature conchocelis culture was blended (IKA ULTRA-TURRAX T25 Basic S2) before 0.4 g fresh weight (fine scale, A&D HR-120) was transferred to 100-mL glass flasks filled with 100 mL sterile and nutrient enriched (as stated above) seawater. The stocking density was chosen as it is in the range of stocking densities commonly used in macroalgae cultivation (He and Yarish 2006;Pereira et al 2006;Abreu et al 2011;Zhong et al 2016;Ashkenazi et al 2018). To investigate the effect of temperature on the conchospore release, mature conchocelis were cultivated in triplicate for three weeks at 9, 12, 15 and 18°C under a short photoperiod (8:16 h light:dark) and 70 μmol photons m −2 s −1 (Fig.…”