16 DECEMBER • WORLD AQUACULTURE • WWW.WAS.ORG 3. Environmental sustainability: It does not require freshwater or arable land and can help mitigate climate change by absorbing CO2 and producing oxygen. Especially the coastal areas of Saudi Arabia are severely lacking in freshwater resources. Based on the above purpose, FAO and MEWA have implemented relevant field experiments since 2023. Selecting the potential species Two species, Sarconema filiformis and Gracilaria multipartita have been selected as genetic resources with the most potential in Saudi Arabia. The criteria used for selecting the two potential species included: 1. Commercial value based on their chemical and/ or nutritional composition from previous studies made elsewhere. 2. Adaptation to economical and straightforward rope and net cultivation systems in the sea through vegetative/ clonal propagation in shallow protected areas, in both the Red Sea and the Arabian Gulf. 3. Fast growth strains with chemical resistance to herbivores. 3. Adaptation to extreme temperatures during the entire year (Figure 3). Notably, Sarconema filiformis and Gracilaria multipartita are suitable for commercial use in food, biotech applications, carrageenan production, bioplastics, and biostimulants (Figure 4). The pilot projects with small-scale producers FAO and MEWA carried out three pilot projects with smallscale producers in the Farasan Islands (southern coastline, Red Sea), Jeddah (western coastline, Red Sea), and Al-Khobar (northern coastline, Arabian Gulf) in 2024 (Figure 5). The primary purpose was to evaluate the growth of the selected species involving coastal communities, research institutions and the MEWA technical staff. Based on biomass increments at the Jeddah site under cultivation, a 4.34% DGR (Daily Growing Rate), was attained, which is considered optimal for tropical species. The biomass growth recorded in Farasan reached 2.34%, which is average for some Southeast Asian countries, but lower when compared to India and Indonesia, at 4-6%. The results in the Al-Khobar site, due to the high salinity and water temperature, were not as expected. Small-scale producers initiate seaweed production in Al-Lith, the Jeddah area According to the results of pilot projects with smallscale producers, we selected the Al-Lith area near Jeddah for small-scale production and feasibility analysis. The proposed farm will utilize a floating raft culture method in coastal waters. A total of 350 rafts (floating frames) will be deployed in a suitable nearshore site. Each raft is designed to hold up to 300 kg of live Gracilaria attached via tubular nets. Raft culture is a proven technique for Gracilaria farming – for example, a 3 × 3 m bamboo raft can yield around 200 kg of wet seaweed in a 45-day cycle under good conditions. In our plan, each raft (approximately 3.66 × 3.66 m) is slightly larger and stocked to a capacity of 300 kg, capitalizing on the favorable growth conditions in the Red Sea (Figures 6-8). The growing season for Gracilaria in the Jeddah region spans from October to May, approximately an 8-month window when water temperatures and conditions are optimal. Gracilaria exhibits a DGR of about 4.34% per day in this region (as observed in pilot studies). This is within the typical range reported for raft-cultured Gracilaria (~3–5% daily). Such rapid growth enables multiple harvest cycles throughout the season. Based on the DGR and local farming practice, we anticipate ~5 complete cycles (45–50 days each) from October to May. In each cycle, rafts are seeded with cuttings of seaweed and harvested once FIGURE 3. Drying process in a high temperature weather location. Source: Raul Rincones. FIGURE 4. Sampling of local seaweed species Gracillaria multipartita. Source: Raul Rincones.
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