Digital library

  • IMTA with Gracilaria vermiculophylla: Productivity and nutrient removal performance of the seaweed in a land-based pilot scale system

    The use of ecological engineering tools for the development of a more sustainable aquaculture is crucial. In this context, seaweed based Integrated Multi-Trophic Aquaculture (IMTA) systems are being designed to mitigate the environmental problems caused by several forms of fed aquaculture. Several macroalgal species, namely some from the genus Gracilaria, have been shown to be efficient biofilters,. Gracilaria vermiculophylla thrives in Ria de Aveiro lagoon, Portugal (40°38N, 8°43°W). It has been an unexploited resource for the production of agar. A seaweed cultivation system with 1200 L tanks was installed at a sole and turbot land-based aquaculture facility to evaluate the potential of this species as the biofilter component of an IMTA system. A year round, full factorial experiment was done, testing for the influence of stocking density (3, 5 and 7 kg m− 2 (fw)), water exchange rate (100 and 200 L h− 1) and time of the year on G. vermiculophylla's relative growth rates (RGR), productivity and nutrient removal.

    G. vermiculophylla was able to maintain a good overall performance; however, results indicate that the culture conditions require adaptations throughout the year in order to attain successful productivities. In general, biomass production and nutrient removal were negatively related to the cultivation densities in the system. In the tanks seeded with 3 kg fw m− 2, the production of G. vermiculophylla was 0.7 ± 0.05 kg dw m− 2 month− 1; this biomass removed 221 ± 12.82 g m− 2 month− 1 of carbon and 40.54 ± 2.02 g m− 2 month− 1 of nitrogen (± 0.03% of the monthly fish N inputs). Temperature and light were the main environmental factors conditioning the growth and nutrient removal performance of the seaweed. With the appropriate upscaling, this pilot IMTA system is ready for implementation at fish aquaculture operations. G. vermiculophylla has proved to be an efficient component of land-based IMTA systems with environmental and potentially economic benefits for the fish farm.

    Author(s): Yarish, Charles Isabel Sousa-Pinto, Alejandro H. Buschmann, Rui Pereira, Maria H. Abreu

  • Improving Water Use Efficiency in Semi-Arid Regions through Integrated Aquaculture/Agriculture

    Two experiments were performed in the Bekaa plain in Lebanon to evaluate the feasibility of integrating aquaculture with established agriculture production in order to increase water productivity. Both experiments consisted of four plant management treatments: 1) Aquaculture effluent irrigation and no fertilizer; 2) aquaculture effluent irrigation and inorganic fertilizer; 3) well water irrigation and no fertilization; and 4) well water irrigation with inorganic fertilizer. In the first experiment, tilapia growth and radish production using aquaculture effluent were evaluated. All fish survived and grew, and radish production was improved by irrigating with aquaculture effluent. In the second experiment, maize (Zea mays) in large plots was irrigated with aquaculture effluent. Irrigation with effluent water improved maize production and improved soil nitrogen availability. In both experiments, fish production improved water value index and water use efficiency. Results suggest that aquaculture effluent can supplant inorganic fertilizers and could actually yield better crop production.

    Author(s): Joly Ghanaw, Mustafa Haidar, Nadim Farajalla, Hanafy Holail, Mohammed K. Owaied, I. Patrick Saoud, Sami Abdul-Rahman

  • Improving the Information Base for Aquatic Genetic Resources for The State of the World’s Aquatic Genetic Resources

    The International Expert Workshop on Improving the Information Base for Aquatic Genetic Resources for The State of the World’s Aquatic Genetic Resources was convened by FAO in collaboration with the Spanish Aquaculture Observatory Foundation (FOESA) from 1–4 March 2011 in Madrid, Spain.

    The workshop was attended by international aquatic genetic resources database experts, representatives of regional aquaculture and fisheries bodies and networks, the consultants responsible for the preparation of the background papers presented at the event, and representatives of international organizations involved in the topic.

    The main objectives of the workshop were to discuss and to review two background papers that are part of the work of the FAO Fisheries and Aquaculture Department with the FAO Commission on Genetic Resources for Food and Agriculture, which in 2007 included aquatic genetic resources into its Multi-Year Programme of Work.

    Author(s): Matthias Halwart , Ruth García Gómez, Kathrin Hett, Devin M. Bartley

  • Improving the Food Quality of Sea Urchins Collected from Barren Grounds by Short-Term Aquaculture under Controlled Temperature

    In west Hokkaido, there are many barren grounds where Mesocentrotus nudus isabundant. These sea urchins have poor commercial value due to their thin gonads, but can becomemarketable by intensive feeding for gonad enhancement. In general, the quality of sea urchingonads as food products decreases as gametogenesis progresses.Mature ovaries and testes arenot suitable as food products because of the unpleasant taste caused by gamete content and themelting appearance caused by gamete flow via breakage of the gonoduct. Immature to pre-maturegonads that contain predominantly nutritive phagocytes (somaticnutrient storage cells) and notcopious gametes have a higher commercial value. Thus, enhancingthe nutrient accumulation intonutritive phagocytes plus suppressing gametogenesis is advantageous for sea urchin aquaculture.We are developing short-term aquaculture techniques to improvethe food quality of M. nuduscollected from barren grounds under controlled temperature to suppress gametogenesis. RearingM. nudus under a low temperature between summer and autumn hasproved to be effective toincrease the gonad size without the quality deterioration caused by maturation.

    Author(s): Kazuhiro TAKAHASHI, Sayumi SAWAGUCHI, Natsuki HASEGAWA, Yuko MURATA, Tatsuya UNUMA

  • Importance of Seaweeds and Extractive Species in Global Aquaculture Production

    The FAO recently published its biennial State of World Fisheries and Aquaculture up to 2018. The FAO continues to treat the seaweed aquaculture sector as a different category, with separate tables and comments in different sections. As this could lead to a distorted view of total world aquaculture, the statistical information provided by FAO was revisited and data regarding the seaweed aquaculture sector were integrated with data of the other sectors of the world aquaculture production, to reach different conclusions: (1) aquaculture represents 54.1% of total world fisheries and aquaculture production; (2) marine and coastal aquaculture represents 55.2% of total world aquaculture production; (3) seaweeds represent 51.3% of total production of marine and coastal aquaculture; (4) 99.5% of seaweed mariculture production is concentrated in Asia; (5) 8 seaweed genera provide 96.8% of world seaweed mariculture production; (6) 2 seaweed genera are the most produced organisms in mariculture in the world; (7) the value of the seaweed aquaculture sector could be much larger, especially if a monetary value was attributed to the ecosystem services provided by seaweeds; and (8) total extractive aquaculture is slightly larger (50.6%) than total fed aquaculture (49.4%).

    Author(s): Albert G. J. Tacon, Thierry Chopin

  • Impact of wastewater cultivation on pollutant removal, biomass production, metabolite biosynthesis, and carbon dioxide fixation of newly isolated cyanobacteria in a multiproduct biorefinery paradigm

    The impact of wastewater cultivation was studied on pollutant removal, biomass production, and biosynthesis of high-value metabolites by newly isolated cyanobacteria namely Acaryochloris marina BERC03, Oscillatoria sp. BERC04, and Pleurocapsa sp. BERC06. During cultivation in urabn wastewater, its pH used to adjust from pH 8.0 to 11, offering contamination-free cultivation, and flotation-based easy harvesting. Besides, wastewater culti- vation improved biomass production by 1.3-fold when compared to control along with 3.54–4.2 gL-1 of CO2 fixation, concomitantly removing suspended organic matter, total nitrogen, and phosphorus by 100%, 53%, and 88%, respectively. Biomass accumulated 26–36% carbohydrates, 15–28% proteins, 38–43% lipids, and 6.3–9.5% phycobilins, where phycobilin yield was improved by 1.6-fold when compared to control. Lipids extracted from the pigment-free biomass were trans-esterified to biodiesel where pigment extraction showed no negative impact on quality of the biodiesel. These strains demonstrated the potential to become feedstock of an integrated bio- refinery using urban wastewater as low-cost growth media.

    Author(s): Ayesha Shahid, Muhammad Usman, Zahida Atta, Syed Ghulam Musharraf, Sana Malik, Ali Elkamel, Muhammad Shahid, Nuha Abdulhamid Alkhattabi , Munazza Gull, Muhammad Aamer Mehmood

  • Hydrothermal Liquefaction of Macroalgae Enteromorpha prolifera to Bio-oil

    Marine macroalgae Enteromorpha prolifera, one of the main algae genera for green tide, was converted to bio-oil by hydrothermal liquefaction in a batch reactor at temperatures of 220−320 °C. The liquefaction products were separated into a dichloromethane-soluble fraction (bio-oil), water-soluble fraction, solid residue, and gaseous fraction. Effects of the temperature, reaction time, and Na2CO3 catalyst on the yields of liquefaction products were investigated. A moderate temperature of 300 °C with 5 wt % Na2CO3 and reaction time of 30 min led to the highest bio-oil yield of 23.0 wt %. The raw algae and liquefaction products were analyzed using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, gas chromatography−mass spectrometry (GC−MS), and 1H nuclear magnetic resonance (NMR). The higher heating values (HHVs) of bio-oils obtained at 300 °C were around 28−30 MJ/kg. The bio-oil was a complex mixture of ketones, aldehydes, phenols, alkenes, fatty acids, esters, aromatics, and nitrogen-containing heterocyclic compounds. Acetic acid was the main component of the water-soluble products. The results might be helpful to find a possible strategy for use of byproducts of green tide as feedstock for bio-oil production, which should be beneficial for environmental protection and renewable energy development.

    Author(s): Jian-Min Chen, Hongbo Fu, Shicheng Zhang, Liang Zhang, Dong Zhou

  • Hydrothermal carbonization of microalgae II. Fatty acid, char, and algal nutrient products

    A process for isolation of three products (fatty acids, chars and nutrient-rich aqueous phases) from the hydrothermal carbonization of microalgae is described. Fatty acid products derived from hydrolysis of fatty acid ester groups in the microalgae were obtained in high yield and were found to be principally adsorbed onto the char also created in the process. With the highest lipid-containing microalga investigated, 92% of the fatty acids isolated were obtained by solvent extraction of the char product, with the remaining 8% obtained by extraction of the acidified filtrate. Obtaining the fatty acids principally by a solid–liquid extraction eliminates potential emulsification and phase separation problems commonly encountered in liquid–liquid extractions. The aqueous phase was investigated as a nutrient amendment to algal growth media, and a 20-fold dilution of the concentrate supported algal growth to a level of about half that of the optimal nutrient growth medium. Uses for the extracted char other than as a solid fuel are also discussed. Results of these studies indicate that fatty acids derived from hydrothermal carbonization of microalgae hold great promise for the production of liquid biofuels.

    Author(s): Kenneth J. Valentas, Marc G. von Keitz, Paul A. Lefebvre, Frederick J. Schendel, Michael J. Sadowsky, Laurie A. Harned, Lindsey R. Jader , Steven M. Heilmann

  • How Seaweed is used in Ireland

    The contemporary uses of seaweed in Ireland are many and various. Seaweed is gathered as food, processed and used as fertiliser, forms an ingredient in many cosmetics and spa treatments, and is the subject of biotechnological and pharmaceutical research.

    Author(s): Stefan Kraan

  • History, Current Status, and the Future of Open Ocean Aquaculture Permitting and Leasing in Hawaii

    It is a necessary conclusion that ultimately the scientific insights into the impacts of open ocean aquaculture must be turned into policies, laws, and regulations governing industry development. Hawaii established a state law in 1986 to allow leasing of state marine waters for aquaculture
    and ocean energy purposes. Due to legislature concerns, however, the final statute only had limited applicability for small research projects (Corbin and Young 1997). Hawaii amended its state law in 1999 to correct these problems and encourage large-scale commercial aquaculture use of offshore waters (Cates et al. 2001). A coalition of state, university, and private sector interests engaged the public and supported this far-reaching change in the state legislature because: hatchery technology for mass rearing of local species was available; growout technology suitable for local open ocean conditions was commercially available; a federally funded, large- scale demonstration of cage culture, gathering real data, was underway (Ostrowski et al. 2001); experienced ocean interests were ready to invest in commercial aquaculture projects; and there existed strong state and public support for aquaculture for economic development.

    Author(s): John S. Corbin

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