Experimental field cultivation of the agar yielding seaweed Gracilaria edulis was carried out on long line coir ropes and nets at four locations in the lagoon of Minicoy Island during the period March-June '90. The plants of G. edulis collected from Krusadai Island (Mandapam) and Kavaratti Island (Lakshadweep) were transported to Minicoy by rail and ship and used as seed material. The seedlings grew very well at two places and yield obtained after 60 days growth was a seven fold increase over the quantity of seed material. This may be attributed to the clarity of water, low sedimentation and less epiphytic growth in these two locations. The growth of G. edulis introduced in other two palces was affected by heavy sedimentation and attachment of several other algae on seedlings, coir ropes and nets. The present experiment shows the high potential for the successful cultivation of this agarophyte in the lagoon of Minicoy.
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The Seaweed Consultant was hired by the FAO to assist the Ministry of Fisheries and Agriculture (MOFA) through the Oceanographic Society of Maldives (OSM) in introducing the Eucheuma (seaweed) farming technology at Gamu Island, Laamu atoll, Maldives.
Several prior attempts to introduce seaweed fanning in the Maldives had failed, mainly due to the problem of fish grazers. The farming technique used in the Philippines, Malaysia, Indonesia, and Tanzania (monoline system) could not be applied successfully in the Maldives due to the abundance of fish grazers which thrive in the lagoons.
When the consultant arrived in the Maldives in February 1996 for his first one-month technical assistance, he brought a sample of the net-bag propagule holders which he had devised in the Philippines to counter problems such as grazer attacks and losses due to turbulent weather. The floating net-bag technique is described in detail in the project field document No. 2. The new technique eliminated also the tedious process of tying every propagule to the monoline, thereby saving a lot of labour cost. When he visited the test station for the Eucheuma at Gamu island, he observed that the plants were almost consumed by the grazers since the propagules were cultured using the monoline system. The remaining plants were untied from the monoline and then brought to another site where the current was good and where the water motion was consistent. The five kilograms of cottonii which were salvaged were planted, placing them in 10 net-bags at the rate of 1/2 kilogram/bag. The propagule line containing the 10 net-bags was installed in the water in the selected area. After 15 days, the plants recovered and showed a good growth rate, which was computed to be 3-4% daily.
The seedlings in the net-bags were split continuously every month. Five hundred net-bags were procured to contain the rapidly increasing volume of seedstocks. By September, 1996, OSM reported that the seedling inventory was already 600 kilograms, requiring additional net-bags (35,000 pieces).
At this time the plant growth had increased to about 5-6% daily, which means that the biomass was doubling every 10-15 days.
In March, 1997, the Seaweed Consultant carried out his second one-month mission to evaluate the performance of the seaweed culture and to introduce the post-harvest technology to the project staff and workers.
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Farming Seaweed in Kiribati: A practical guide for seaweed farmers
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Three isocaloric (3.5 kcal/g) ingredient blends containing 20, 30, and 40% distiller-dried grains with solubles (DDGS) along with 5% whey were prepared with a net protein content adjusted to 28% (wet basis [wb]). Other ingredients in the blends included soy flour, corn flour, fish meal, vitamin, and mineral mix. These blends were extruded in a single-screw extruder at 15, 20, and 25% (wb) moisture content and at 130 and 160 rpm screw speeds. Compared to previous research, the durability and unit density of the extrudates in this study were found to increase substantially by the addition of whey to the blends. Increasing the DDGS content from 20 to 40% resulted in a 5.8 and 16.8% increase in extrudate moisture content and redness, respectively, but produced a decrease of 11.2% in brightness and 3.6% in yellowness of the extrudates. Increasing the moisture content of the ingredient blends from 15 to 25% resulted in an increase of 16.1, 8.7, and 9.3% in moisture content, durability, and redness, respectively, but a decrease of 9.8 and 5.6%, respectively, in brightness and yellowness of the extrudates. Neither DDGS level nor screw speed significantly affected extrudate durability or unit density. In fact, changing the screw speed had no significant effect on many of the properties of the extrudates studied, except for moisture content, redness, and yellowness. As demonstrated in this study, ingredient moisture content and screw speed are critical considerations when producing extrudates with feed blends containing DDGS; further work is needed to optimize processing conditions and to produce floating feeds.
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Seaweeds are a rich source of protein and can contain up to 47% on the dry weight basis. It is challenging to extract proteins from the raw biomass of seaweed due to resilient cell-wall complexes. Four species of macroalgae were used in this study-two brown, Fucus vesiculosus and Alaria esculenta, and two red, Palmaria palmata and Chondrus crispus. Three treatments were applied individually to the macroalgal species: (I) high-pressure processing (HPP); (II) laboratory autoclave processing and (III) a classical sonication and salting out method. The protein, ash and lipid contents of the resulting extracts were estimated. Yields of protein recovered ranged from 3.2% for Fucus vesiculosus pre-treated with high pressure processing to 28.9% protein recovered for Chondrus crispus treated with the classical method. The yields of protein recovered using the classical, HPP and autoclave pre-treatments applied to Fucus vesiculosus were 35.1, 23.7% and 24.3%, respectively; yields from Alaria esculenta were 18.2%, 15.0% and 17.1% respectively; yields from Palmaria palmata were 12.5%, 14.9% and 21.5% respectively, and finally, yields from Chondrus crispus were 35.2%, 16.1% and 21.9%, respectively. These results demonstrate that while macroalgal proteins may be extracted using either physical or enzymatic methods, the specific extraction procedure should be tailored to individual speci
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Macroalgae are one of potential sources for carotenoids, such as fucoxanthin, which are consumed by humans and animals. This carotenoid has been applied in both the pharmaceutical and food industries. In this study, extraction of fucoxanthin from wet brown seaweed Undaria pinnatifida (water content was 93.2%) was carried out with a simple method using liquefied dimethyl ether (DME) as an extractant in semi-continuous flow-type system. The extraction temperature and absolute pressure were 25 °C and 0.59 MPa, respectively. The liquefied DME was passed through the extractor that filled by U. pinnatifida at different time intervals. The time of experiment was only 43 min. The amount of fucoxanthin could approach to 390 μg/g dry of wet U. pinnatifida when the amount of DME used was 286 g. Compared with ethanol Soxhlet and supercritical CO2 extraction, which includes drying and cell disruption, the result was quite high. Thus, DME extraction process appears to be a good method for fucoxanthin recovery from U. pinnatifida with improved yields.
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Ecological Aquaculture is an online resource featuring blogs, publications, links and information on combining traditional and modern aquaculture practices. Costa-Pierce's article emphasizes that the "blue revolution" is not a new idea.
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In this study, Saccharina japonica was treated with pressurized hot water extraction (PHWE) at a temperature of 180 °C–420 °C and pressure between 13 bar and 520 bar. The obtained hydrolysate was investigated for their yield, total organic carbon (TOC), pH, Maillard reaction products, viscosity, color, and amino acid, mineral, and monosaccharide contents. The extraction yield increased with an increase in temperature and varied from 72.21% to 98.91%. TOC, pH, and potassium and sodium content increased, whereas viscosity decreased, with an increase in temperature. Essential amino acids such as valine and lysine and non-essential amino acids such as aspartic acid, glutamic acid, glycine, and tyrosine recovered well at low temperature. The content of heavy metals such as arsenic, cadmium, mercury, and lead was very low in the obtained hydrolysate. The maximum amount of total amino acids was recovered at 180 °C/13 bar (761.95 ± 14.54 mg/g). The level of main monosaccharides such as glucose (6.70 g/L), fructose (8.40 g/L), and mannitol (17.50 g/L) was found to be very high at 180 °C/13 bar. The results indicated that the pressurized hot water extract of S. japonica has good potential for use in the fermentation industry and can be used as human food.
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Although Korea is third in seaweed production and second in shellfish production globally, this is the first study evaluating ecosystem services of seaweed and shellfish aquaculture in Korea. The objective of this study is to evaluate nutrient bioextraction capacities of major seaweed and shellfish species aquacultured in Korea. C (C) removal of three major aquacultured seaweed species, Neopyropia yezoensis, Saccharina japonica, and Undaria pinnatifida were 24,247, 8,423, and 12,758 tons, respectively, in 2016. N (N) removal of these species was 4,088, 732, and 1,244 tons, respectively. The C and N removal of the Pacific oysters (Crassostrea gigas) were 14,693 and 1,050 tons, respectively. Manila clams (Venerupis philippinarum) removed 2,120 tons of C and 136.5 tons of N. Together, 161,846 tons of CO2 and 7,251 tons of N were removed by three major seaweed species and two shellfish species. These values are significant amounts, equivalent to 5.7% of CO2 and 8.6% of N discharged from all wastewater treatment plants in Korea. These results suggest that nutrient bioextraction by aquacultured seaweed and shellfish can be a cost efficient, affordable, and equitable solution for coastal nutrient management programs in Korea and elsewhere.
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To evaluate the potential of using Corn Dried Distiller's Grain with Soluble (DDGS) as a potential alternative ingredient in feeds for the Pacific White Shrimp, Litopenaeus vannmei.
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Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
Funding for this web portal is provided by the World Wildlife Fund and the University of Hawaii-Hilo.