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For millennia, coastal and marine ecosystems have adapted and flourished in the Red Sea’s unique environment. Surrounded by deserts on all sides, the Red Sea is subjected to high dust inputs and receives very little freshwater input, and so harbors a high salinity. Coral reefs, seagrass meadows, and mangroves flourish in this environment and provide socio-economic and environmental benefits to the bordering coastlines and countries. Interestingly, while coral reef ecosystems are currently experiencing rapid decline on a global scale, those in the Red Sea appear to be in relatively better shape. That said, they are certainly not immune to the stressors that cause degradation, such as increasing ocean temperature, acidification and pollution. In many regions, ecosystems are already severely deteriorating and are further threatened by increasing population pressure and large coastal development projects. Degradation of these marine habitats will lead to environmental costs, as well as significant economic losses. Therefore, it will result in a missed opportunity for the bordering countries to develop a sustainable blue economy and integrate innovative nature-based solutions. Recognizing that securing the Red Sea ecosystems’ future must occur in synergy with continued social and economic growth, we developed an action plan for the conservation, restoration, and growth of marine environments of the Red Sea. We then investigated the level of resources for financial and economic investment that may incentivize these activities. This study presents a set of commercially viable financial investment strategies, ecological innovations, and sustainable development opportunities, which can, if implemented strategically, help ensure long-term economic benefits while promoting environmental conservation. We make a case for investing in blue natural capital and propose a strategic development model that relies on maintaining the health of natural ecosystems to safeguard the Red Sea’s sustainable development.

A 12-week long feeding experiment was initiated to evaluate the effect of dietary supplementation of red algae, Gracilaria arcuata, on the growth performance, feed utilization and body composition of Nile tilapia Oreochromis niloticus (Linnaeus, 1758). The fish were fed with an algae-free control diet (C) and three experimental diets which replaced conventional fish meal with varying levels of dried G. arcuata (20%, 40% and 60%, represented as G20, G40 and G60, respectively). The growth parameters of final weight (FW), weight gain (WG), percentage of weight gain (WG%), daily growth rate (DGR) and specific growth rate (SGR) were significantly reduced (P

Nature is perceived and valued in starkly different and oftenconflicting ways. This paper presents the rationale for theinclusive valuation of nature's contributions to people (NCP) indecision making, as well as broad methodological steps fordoing so. While developed within the context of theIntergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), this approach is more widely applicable toinitiatives at the knowledge?policy interface, which require apluralistic approach to recognizing the diversity of values. Weargue that transformative practices aiming at sustainablefutures would benefit from embracing such diversity, which require recognizing and addressing power relationships across stake holder groups that hold different values on human nature relations and NCP Fil: Pascual, Unai. University Of Cambridge; Reino Unido Fil: Balvanera, Patricia. Universidad Nacional Autónoma de México; México Fil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Pataki, György. Corvinus University of Budapest; Hungría Fil: Roth, Eva. University of Southern Denmark; Dinamarca Fil: Stenseke, Marie. University Goteborg; Suecia Fil: Watson, Robert T.. University of East Anglia; Reino Unido Fil: Basak Dessane, Esra. Project House; Turquía Fil: Islar, Mine. Lund University; Suecia Fil: Kelemen, Eszter. Environmental Social Science Research Group; Hungría Fil: Maris, Virginie. Centre d’Ecologie Fonctionnelle et Evolutive; Francia Fil: Quaas, Martin. Kiel University; Alemania Fil: Subramanian, Suneetha M. United Nations University; Japón Fil: Wittmer, Heidi. Helmholtz-Centre for Environmental Research; Alemania Fil: Adlan, Asia. University of Khartoum; Sudán Fil: Ahn, SoEun. Korea Environment Institute; Corea del Sur Fil: Al-Hafedh, Yousef S. King Abdulaziz City for Science & Technology; Arabia Saudita Fil: Amankwah, Edward. Center for Environmental Governance; Ghana Fil: Berry, Pam. University of Washington; Estados Unidos Fil: Bilgin, Adem. University of Oxford; Reino Unido Fil: Breslow, Sara J. Ministry of Forestry and Water Affairs of Turkey; Turquía Fil: Bullock, Craig. University College Dublin; Reino Unido Fil: Caceres, Daniel Mario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Desarrollo Rural; Argentina Fil: Daly-Hassen, Hamed. University of Carthage; Túnez Fil: Figueroa, Eugenio. Universidad de Chile; Chile Fil: van den Belt, Marjan. Victoria University of Wellington; Nueva Zelanda Fil: Verma, Madhu. Indian Institute of Forest Management; India Fil: Wickson, Fern. GenØk Centre for Biosafety, Siva innovasjonssenter; Noruega Fil: Yagi, Noboyuki. The University of Tokyo; Japón

Growth, production and biofiltration rates of seaweed, Ulva lactuca were investigated at two stocking densities (3 kg and 6 kg m−2) and two effluent flow rates (5.4 and 10.8 m3 day−1) to optimize an integrated mariculture system at Saudi Red Sea coast. effluents from fish-rearing tank, stocked with 200 kg fish (Oreochromis spilurus), fed to six seaweed tanks via sedimentation tank. Fish growth (weight gain 1.75 g fish day−1), net production (NP, 10.16 kg m−3) and survival (94.24%) were within acceptable limits. Ulva showed significantly higher (F = 62.62, d.f. 3, 35; P

Isonitrogenous and isocaloric diets (32% protein, 4.3 Kcal/g) were formulated to replace fishmeal by single cell protein (SCP) from two yeasts, Saccharomyces cerevisiae and Candida utilis, grown on date (Phoenix dactylifera) processing waste in diets for two size groups (avg 15.39 g and 25.14 g) of juvenile Nile tilapia (Oreochromis niloticus). A control diet (T1) with fishmeal and six experimental diets (S1, S2, and S3 with S. cerevisiae, and C1, C2, and C3 with C. utilis) each containing 11.6%, 23.2%, and 34.2% yeast as SCP were prepared to replace 25%, 50%, and 75% of fishmeal, respectively. Tilapia fed on the control and experimental diets (S1, S2, C1, C2) with 25% and 50% replacement of fishmeal showed better growth and feed utilization. Fish fed on diets S3 and C3 (75% fishmeal replacement) had significantly (p < 0.05) poorer growth suggesting that yeast SCP can replace up to 50% of fishmeal in juvenile tilapia diets.

Seaweeds absorb inorganic nutrient wastes from mariculture and reduce their undesirable environmental effects. Mariculture in Saudi Arabia is increasing rapidly, thus, to exploit aquaculture wastes and to reduce coastal pollution risks, local seaweeds were cultured using mariculture effluents in integration on the Red Sea coast. The aim of the present study was to test integrated aquaculture of seaweed and marine fish (Oreochromis spilurus) for the first time in Saudi Arabia and to determine the seaweeds, Ulva lactuca and Gracilaria arcuata, biomass production and inorganic nutrient bioremediation capabilities. Results showed that G. arcuata grew at a significantly higher rate (2.71% wet weight day−1) than U. lactuca (1.77% wet weight day−1). The biomass yield (42.38 g wet weight m−2 day−1) and net yield (91.11 g wet weight day−1) of G. arcuata were also significantly higher than U. lactuca (27.39 g wet weight m−2 day−1 and 58.89 g wet weight day−1, respectively). Gracilaria arcuata removed 0.45 g m−2 day−1 of total ammonia nitrogen (TAN) with 80.15% removal efficiency and 1.03 g m−2 day−1 of soluble phosphate with 41.06% efficiency. Ulva lactuca removed 0.42 g m−2 day−1 of TAN with 83.06% removal efficiency and 1.07 g m−2 day−1 of soluble phosphate with 41.11% efficiency. Total tissue carbon of both species reached 25.1–26.9% and nitrogen content reached 3.0–3.2% of dry weight. The C/N ratio for both seaweeds was

An indoor aquaponic system (i.e., the integration of fish culture with hydroponic plant production in a recirculating setup) was operated for maximizing water reuse and year-round intensive food production (Nile tilapia, Oreochromis niloticus, and leaf lettuce) at different fish feed to plants ratios. The system consisted of a fish culture component, solid removal component, and hydroponic component comprising six long channels with floating styrofoam rafts for holding plants. Fish culture effluents flowed by gravity from the fish culture component to the solid removal component and then to the hydroponic component. Effluents were collected in a sump from which a 1-horsepower in-line pump recirculated the water back to the fish culture tanks at a rate of about 250 L/min. The hydroponic component performed as biofilter and effectively managed the water quality. Fish production was staggered to harvest one of the four fish tanks at regular intervals when fish attained a minimum weight of 250 g. Out of the total eight harvests in 13 mo, net fish production per harvest averaged 33.5 kg/m3 of water with an overall water consumption of 320 L/kg of fish produced along with the production of leaf lettuce at 42 heads/m2 of hydroponic surface area. Only 1.4% of the total system water was added daily to compensate the evaporation and transpiration losses. A ratio of 56 g fish feed/m2 of hydroponic surface effectively controlled nutrient buildup in the effluents. However, plant density could be decreased from 42 to 25–30 plants/m2 to produce a better quality lettuce.

Isocaloric diets with 25,30, 35,40, and 45% protein levels were fed to triplicate groups of juvenile (1.96 ± 0.2 g) freshwater prawn, Macrobrachium rosenbergii, at 3% to 6% body weight per day for 168 days. No significant effect of dietary protein level on weight gain, specific growth rate, and survival was found (P > 0.05). Highest wet weight gain was recorded for prawns fed 35% protein diet and the poorest for prawn fed 25% and 45% protein diet. Protein efficiency ratio (PER) progressively and significantly (P < 0.05) decreased with increasing level of dietary protein. The results of the present study suggest that dietary protein requirement of freshwater prawn is 35%.

Recirculating greenwater aquaculture technology is an appropriate method for producing commercial quantities of tilapia in locations that have water scarcity. Greenwater systems achieve three major goals; higher fish production, maximum water recycling (> 98%) and nutrient utilization. Some nutrients are recycled back in this system to sustain the development of photosynthetic algae and nitrifying bacteria creating a “suspended growth treatment process” that maintains adequate water quality. In this study, the greenwater system was implemented in triplicate, each replicate had a fiberglass fish culture tank and a cone bottomed clarifier for solid filtration. Water from the fish culture tanks is pumped to the cone clarifier through the airlift and the outflows of the cone clarifiers trickled back to the fish culture tanks at a rate of 7–8 L/minute. The study was designed to compare the performance of a greenwater system with mixed-sex, as well as, all-male tilapia. Culture tanks were stocked at a ...

Three kinds of locally available plastic biofilter media with different configurations (plastic rolls, PVC pipes and scrub pads) were evaluated for their efficiency in organic waste removal from the effluents of an intensive recirculating tilapia culture system. A set of three types of solid-removing filters consisting of screened sedimentation; upflow sand as well as plastic bead filtration accomplished the mechanical filtration. Values of critical metabolic wastes like total ammonia nitrogen (TAN) (0.92 ppm) and nitrite-nitrogen (NO 2 -N) (0.22 ppm) were found to be well within the acceptable limits, while other water quality parameters in the culture water were also maintained within the normal range by the filtration system. Removal rates of 3.46 g TAN/m 3 per day and 0.77 g NO 2 -N/m 3 per day, as well as TAN and NO 2 -N removal efficiencies of 29.37 and 27.3% respectively, were established to be the best for the plastic-roll biofilter medium as compared to PVC-pipe and scrub-pad media. Percent removal of TAN and NO 2 -N per pass of the biofilter (25.49 and 26.3% respectively) and the specific TAN and NO 2 -N removal rates (43 and 9.6 mg/m 2 per day) of plastic rolls were also found to be superior to the other two biofilter media. Pieces of PVC pipes as biofilter medium is recommended to be used in the biofilters in view of their cheaper cost.

This study was conducted to evaluate the effects of stocking density and monosex culture on growth, survival, yield and feed conversion ratio of freshwater prawn Macrobrachium rosenbergii in concrete tanks. Juvenile prawns with an average weight of 1.8 g were stocked into triplicate tanks at densities of 5, 10, 15 and 20 prawns/m2, grown for 168 d and fed a 34% tilapia diet. Stocking density had significant effect on prawns. Final mean body weight decreased with the increasing density, being highest at 5 prawns/m2 (29.6 9). and lowest at 20 prawns/m2 (17.4 g). Total yield increased from 135 g/m2 (1,350 kg/ha) at a density of 5 prawns/m2 to 261 g/m2 (2,610 kg/ha) at density 15/mz to 245 g/m2 (2,450 kg/ha) at 20/mz. Feed conversion ratios were high and ranged from 3.7 (5 prawns/m2) to 5.6 (20 prawns/m2). In monosex culture of freshwater prawns stocked in triplicate tanks at a density of 5 prawns/m2 for 112 d, the all-male population had the best growth performance and feed conversion ratio, followed by the mixed-sex and all-female populations. The all-male population had 99% marketable prawns (>20 g) with an average yield of 159 g/m2 (1,590 kg/ha); the mixed-sex population had 90% marketable prawns and the yield was 135 g/mz (1,350 kg/ha); and the all-female population had 75% marketable prawns with an average yield of 108 g/m2 (1,080 kgha).

Recirculating greenwater aquaculture technology is an appropriate method for producing commercial quantities of tilapia in areas where water is scarce. Greenwater systems achieve better fish production, more than 90% water recycling and nutrient utilization. This study was designed to address the diurnal dynamics of certain water quality parameters in greenwater system. Culture tanks were stocked at a density of 40 fish/m3 with mixed-sex Nile tilapia, Oreochromis niloticus fingerlings and fed ad libitum with floating pellets containing 34% protein. The water temperature was kept 28±1oC, aeration was provided and sludge was collected twice daily. Values of critical chemical parameters in the water were found to be well within the acceptable limits based on diurnal water sampling. @JASEM